# Messages

## Create a Message

`client.Messages.New(ctx, body) (*Message, error)`

**post** `/v1/messages`

Send a structured list of input messages with text and/or image content, and the model will generate the next message in the conversation.

The Messages API can be used for either single queries or stateless multi-turn conversations.

Learn more about the Messages API in our [user guide](https://docs.claude.com/en/docs/initial-setup)

### Parameters

- `body MessageNewParams`

  - `MaxTokens param.Field[int64]`

    The maximum number of tokens to generate before stopping.

    Note that our models may stop _before_ reaching this maximum. This parameter only specifies the absolute maximum number of tokens to generate.

    Set to `0` to populate the [prompt cache](https://docs.claude.com/en/docs/build-with-claude/prompt-caching#pre-warming-the-cache) without generating a response.

    Different models have different maximum values for this parameter.  See [models](https://docs.claude.com/en/docs/models-overview) for details.

  - `Messages param.Field[[]MessageParamResp]`

    Input messages.

    Our models are trained to operate on alternating `user` and `assistant` conversational turns. When creating a new `Message`, you specify the prior conversational turns with the `messages` parameter, and the model then generates the next `Message` in the conversation. Consecutive `user` or `assistant` turns in your request will be combined into a single turn.

    Each input message must be an object with a `role` and `content`. You can specify a single `user`-role message, or you can include multiple `user` and `assistant` messages.

    If the final message uses the `assistant` role, the response content will continue immediately from the content in that message. This can be used to constrain part of the model's response.

    Example with a single `user` message:

    ```json
    [{"role": "user", "content": "Hello, Claude"}]
    ```

    Example with multiple conversational turns:

    ```json
    [
      {"role": "user", "content": "Hello there."},
      {"role": "assistant", "content": "Hi, I'm Claude. How can I help you?"},
      {"role": "user", "content": "Can you explain LLMs in plain English?"},
    ]
    ```

    Example with a partially-filled response from Claude:

    ```json
    [
      {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
      {"role": "assistant", "content": "The best answer is ("},
    ]
    ```

    Each input message `content` may be either a single `string` or an array of content blocks, where each block has a specific `type`. Using a `string` for `content` is shorthand for an array of one content block of type `"text"`. The following input messages are equivalent:

    ```json
    {"role": "user", "content": "Hello, Claude"}
    ```

    ```json
    {"role": "user", "content": [{"type": "text", "text": "Hello, Claude"}]}
    ```

    See [input examples](https://docs.claude.com/en/api/messages-examples).

    Note that if you want to include a [system prompt](https://docs.claude.com/en/docs/system-prompts), you can use the top-level `system` parameter — there is no `"system"` role for input messages in the Messages API.

    There is a limit of 100,000 messages in a single request.

    - `Content []ContentBlockParamUnionResp`

      - `[]ContentBlockParamUnionResp`

        - `type TextBlockParamResp struct{…}`

          - `Text string`

          - `Type Text`

            - `const TextText Text = "text"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

            - `Type Ephemeral`

              - `const EphemeralEphemeral Ephemeral = "ephemeral"`

            - `TTL CacheControlEphemeralTTL`

              The time-to-live for the cache control breakpoint.

              This may be one the following values:

              - `5m`: 5 minutes
              - `1h`: 1 hour

              Defaults to `5m`.

              - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

              - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

          - `Citations []TextCitationParamUnionResp`

            - `type CitationCharLocationParamResp struct{…}`

              - `CitedText string`

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndCharIndex int64`

              - `StartCharIndex int64`

              - `Type CharLocation`

                - `const CharLocationCharLocation CharLocation = "char_location"`

            - `type CitationPageLocationParamResp struct{…}`

              - `CitedText string`

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndPageNumber int64`

              - `StartPageNumber int64`

              - `Type PageLocation`

                - `const PageLocationPageLocation PageLocation = "page_location"`

            - `type CitationContentBlockLocationParamResp struct{…}`

              - `CitedText string`

                The full text of the cited block range, concatenated.

                Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndBlockIndex int64`

                Exclusive 0-based end index of the cited block range in the source's `content` array.

                Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

              - `StartBlockIndex int64`

                0-based index of the first cited block in the source's `content` array.

              - `Type ContentBlockLocation`

                - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

            - `type CitationWebSearchResultLocationParamResp struct{…}`

              - `CitedText string`

              - `EncryptedIndex string`

              - `Title string`

              - `Type WebSearchResultLocation`

                - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

              - `URL string`

            - `type CitationSearchResultLocationParamResp struct{…}`

              - `CitedText string`

                The full text of the cited block range, concatenated.

                Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

              - `EndBlockIndex int64`

                Exclusive 0-based end index of the cited block range in the source's `content` array.

                Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

              - `SearchResultIndex int64`

                0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                Counted separately from `document_index`; server-side web search results are not included in this count.

              - `Source string`

              - `StartBlockIndex int64`

                0-based index of the first cited block in the source's `content` array.

              - `Title string`

              - `Type SearchResultLocation`

                - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

        - `type ImageBlockParamResp struct{…}`

          - `Source ImageBlockParamSourceUnionResp`

            - `type Base64ImageSource struct{…}`

              - `Data string`

              - `MediaType Base64ImageSourceMediaType`

                - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

                - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

                - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

                - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

              - `Type Base64`

                - `const Base64Base64 Base64 = "base64"`

            - `type URLImageSource struct{…}`

              - `Type URL`

                - `const URLURL URL = "url"`

              - `URL string`

          - `Type Image`

            - `const ImageImage Image = "image"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type DocumentBlockParamResp struct{…}`

          - `Source DocumentBlockParamSourceUnionResp`

            - `type Base64PDFSource struct{…}`

              - `Data string`

              - `MediaType ApplicationPDF`

                - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

              - `Type Base64`

                - `const Base64Base64 Base64 = "base64"`

            - `type PlainTextSource struct{…}`

              - `Data string`

              - `MediaType TextPlain`

                - `const TextPlainTextPlain TextPlain = "text/plain"`

              - `Type Text`

                - `const TextText Text = "text"`

            - `type ContentBlockSource struct{…}`

              - `Content ContentBlockSourceContentUnion`

                - `string`

                - `[]ContentBlockSourceContentItemUnion`

                  - `type TextBlockParamResp struct{…}`

                  - `type ImageBlockParamResp struct{…}`

              - `Type Content`

                - `const ContentContent Content = "content"`

            - `type URLPDFSource struct{…}`

              - `Type URL`

                - `const URLURL URL = "url"`

              - `URL string`

          - `Type Document`

            - `const DocumentDocument Document = "document"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations CitationsConfigParamResp`

            - `Enabled bool`

          - `Context string`

          - `Title string`

        - `type SearchResultBlockParamResp struct{…}`

          - `Content []TextBlockParamResp`

            - `Text string`

            - `Type Text`

            - `CacheControl CacheControlEphemeral`

              Create a cache control breakpoint at this content block.

            - `Citations []TextCitationParamUnionResp`

          - `Source string`

          - `Title string`

          - `Type SearchResult`

            - `const SearchResultSearchResult SearchResult = "search_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations CitationsConfigParamResp`

        - `type ThinkingBlockParamResp struct{…}`

          - `Signature string`

          - `Thinking string`

          - `Type Thinking`

            - `const ThinkingThinking Thinking = "thinking"`

        - `type RedactedThinkingBlockParamResp struct{…}`

          - `Data string`

          - `Type RedactedThinking`

            - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

        - `type ToolUseBlockParamResp struct{…}`

          - `ID string`

          - `Input map[string, any]`

          - `Name string`

          - `Type ToolUse`

            - `const ToolUseToolUse ToolUse = "tool_use"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Caller ToolUseBlockParamCallerUnionResp`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

              - `Type Direct`

                - `const DirectDirect Direct = "direct"`

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

              - `ToolID string`

              - `Type CodeExecution20250825`

                - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

            - `type ServerToolCaller20260120 struct{…}`

              - `ToolID string`

              - `Type CodeExecution20260120`

                - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

        - `type ToolResultBlockParamResp struct{…}`

          - `ToolUseID string`

          - `Type ToolResult`

            - `const ToolResultToolResult ToolResult = "tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Content []ToolResultBlockParamContentUnionResp`

            - `[]ToolResultBlockParamContentUnionResp`

              - `type TextBlockParamResp struct{…}`

              - `type ImageBlockParamResp struct{…}`

              - `type SearchResultBlockParamResp struct{…}`

              - `type DocumentBlockParamResp struct{…}`

              - `type ToolReferenceBlockParamResp struct{…}`

                Tool reference block that can be included in tool_result content.

                - `ToolName string`

                - `Type ToolReference`

                  - `const ToolReferenceToolReference ToolReference = "tool_reference"`

                - `CacheControl CacheControlEphemeral`

                  Create a cache control breakpoint at this content block.

          - `IsError bool`

        - `type ServerToolUseBlockParamResp struct{…}`

          - `ID string`

          - `Input map[string, any]`

          - `Name ServerToolUseBlockParamName`

            - `const ServerToolUseBlockParamNameWebSearch ServerToolUseBlockParamName = "web_search"`

            - `const ServerToolUseBlockParamNameWebFetch ServerToolUseBlockParamName = "web_fetch"`

            - `const ServerToolUseBlockParamNameCodeExecution ServerToolUseBlockParamName = "code_execution"`

            - `const ServerToolUseBlockParamNameBashCodeExecution ServerToolUseBlockParamName = "bash_code_execution"`

            - `const ServerToolUseBlockParamNameTextEditorCodeExecution ServerToolUseBlockParamName = "text_editor_code_execution"`

            - `const ServerToolUseBlockParamNameToolSearchToolRegex ServerToolUseBlockParamName = "tool_search_tool_regex"`

            - `const ServerToolUseBlockParamNameToolSearchToolBm25 ServerToolUseBlockParamName = "tool_search_tool_bm25"`

          - `Type ServerToolUse`

            - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Caller ServerToolUseBlockParamCallerUnionResp`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

        - `type WebSearchToolResultBlockParamResp struct{…}`

          - `Content WebSearchToolResultBlockParamContentUnionResp`

            - `[]WebSearchResultBlockParamResp`

              - `EncryptedContent string`

              - `Title string`

              - `Type WebSearchResult`

                - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

              - `URL string`

              - `PageAge string`

            - `type WebSearchToolRequestError struct{…}`

              - `ErrorCode WebSearchToolResultErrorCode`

                - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

                - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

                - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

                - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

                - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

                - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

              - `Type WebSearchToolResultError`

                - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

          - `ToolUseID string`

          - `Type WebSearchToolResult`

            - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Caller WebSearchToolResultBlockParamCallerUnionResp`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

        - `type WebFetchToolResultBlockParamResp struct{…}`

          - `Content WebFetchToolResultBlockParamContentUnionResp`

            - `type WebFetchToolResultErrorBlockParamResp struct{…}`

              - `ErrorCode WebFetchToolResultErrorCode`

                - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

                - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

                - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

                - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

                - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

                - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

                - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

                - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

                - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

              - `Type WebFetchToolResultError`

                - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

            - `type WebFetchBlockParamResp struct{…}`

              - `Content DocumentBlockParamResp`

              - `Type WebFetchResult`

                - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

              - `URL string`

                Fetched content URL

              - `RetrievedAt string`

                ISO 8601 timestamp when the content was retrieved

          - `ToolUseID string`

          - `Type WebFetchToolResult`

            - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Caller WebFetchToolResultBlockParamCallerUnionResp`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

        - `type CodeExecutionToolResultBlockParamResp struct{…}`

          - `Content CodeExecutionToolResultBlockParamContentUnionResp`

            Code execution result with encrypted stdout for PFC + web_search results.

            - `type CodeExecutionToolResultErrorParamResp struct{…}`

              - `ErrorCode CodeExecutionToolResultErrorCode`

                - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

                - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `Type CodeExecutionToolResultError`

                - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

            - `type CodeExecutionResultBlockParamResp struct{…}`

              - `Content []CodeExecutionOutputBlockParamResp`

                - `FileID string`

                - `Type CodeExecutionOutput`

                  - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

              - `ReturnCode int64`

              - `Stderr string`

              - `Stdout string`

              - `Type CodeExecutionResult`

                - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

            - `type EncryptedCodeExecutionResultBlockParamResp struct{…}`

              Code execution result with encrypted stdout for PFC + web_search results.

              - `Content []CodeExecutionOutputBlockParamResp`

                - `FileID string`

                - `Type CodeExecutionOutput`

              - `EncryptedStdout string`

              - `ReturnCode int64`

              - `Stderr string`

              - `Type EncryptedCodeExecutionResult`

                - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

          - `ToolUseID string`

          - `Type CodeExecutionToolResult`

            - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type BashCodeExecutionToolResultBlockParamResp struct{…}`

          - `Content BashCodeExecutionToolResultBlockParamContentUnionResp`

            - `type BashCodeExecutionToolResultErrorParamResp struct{…}`

              - `ErrorCode BashCodeExecutionToolResultErrorCode`

                - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

                - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

              - `Type BashCodeExecutionToolResultError`

                - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

            - `type BashCodeExecutionResultBlockParamResp struct{…}`

              - `Content []BashCodeExecutionOutputBlockParamResp`

                - `FileID string`

                - `Type BashCodeExecutionOutput`

                  - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

              - `ReturnCode int64`

              - `Stderr string`

              - `Stdout string`

              - `Type BashCodeExecutionResult`

                - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

          - `ToolUseID string`

          - `Type BashCodeExecutionToolResult`

            - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type TextEditorCodeExecutionToolResultBlockParamResp struct{…}`

          - `Content TextEditorCodeExecutionToolResultBlockParamContentUnionResp`

            - `type TextEditorCodeExecutionToolResultErrorParamResp struct{…}`

              - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

                - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

                - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

              - `Type TextEditorCodeExecutionToolResultError`

                - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

              - `ErrorMessage string`

            - `type TextEditorCodeExecutionViewResultBlockParamResp struct{…}`

              - `Content string`

              - `FileType TextEditorCodeExecutionViewResultBlockParamFileType`

                - `const TextEditorCodeExecutionViewResultBlockParamFileTypeText TextEditorCodeExecutionViewResultBlockParamFileType = "text"`

                - `const TextEditorCodeExecutionViewResultBlockParamFileTypeImage TextEditorCodeExecutionViewResultBlockParamFileType = "image"`

                - `const TextEditorCodeExecutionViewResultBlockParamFileTypePDF TextEditorCodeExecutionViewResultBlockParamFileType = "pdf"`

              - `Type TextEditorCodeExecutionViewResult`

                - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

              - `NumLines int64`

              - `StartLine int64`

              - `TotalLines int64`

            - `type TextEditorCodeExecutionCreateResultBlockParamResp struct{…}`

              - `IsFileUpdate bool`

              - `Type TextEditorCodeExecutionCreateResult`

                - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

            - `type TextEditorCodeExecutionStrReplaceResultBlockParamResp struct{…}`

              - `Type TextEditorCodeExecutionStrReplaceResult`

                - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

              - `Lines []string`

              - `NewLines int64`

              - `NewStart int64`

              - `OldLines int64`

              - `OldStart int64`

          - `ToolUseID string`

          - `Type TextEditorCodeExecutionToolResult`

            - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type ToolSearchToolResultBlockParamResp struct{…}`

          - `Content ToolSearchToolResultBlockParamContentUnionResp`

            - `type ToolSearchToolResultErrorParamResp struct{…}`

              - `ErrorCode ToolSearchToolResultErrorCode`

                - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

                - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

                - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

                - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

              - `Type ToolSearchToolResultError`

                - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

              - `ErrorMessage string`

            - `type ToolSearchToolSearchResultBlockParamResp struct{…}`

              - `ToolReferences []ToolReferenceBlockParamResp`

                - `ToolName string`

                - `Type ToolReference`

                - `CacheControl CacheControlEphemeral`

                  Create a cache control breakpoint at this content block.

              - `Type ToolSearchToolSearchResult`

                - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

          - `ToolUseID string`

          - `Type ToolSearchToolResult`

            - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type ContainerUploadBlockParamResp struct{…}`

          A content block that represents a file to be uploaded to the container
          Files uploaded via this block will be available in the container's input directory.

          - `FileID string`

          - `Type ContainerUpload`

            - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type MidConversationSystemBlockParamResp struct{…}`

          System instructions that appear mid-conversation.

          Use this block to provide or update system-level instructions at a specific
          point in the conversation, rather than only via the top-level `system` parameter.

          - `Content []TextBlockParamResp`

            System instruction text blocks.

            - `Text string`

            - `Type Text`

            - `CacheControl CacheControlEphemeral`

              Create a cache control breakpoint at this content block.

            - `Citations []TextCitationParamUnionResp`

          - `Type MidConvSystem`

            - `const MidConvSystemMidConvSystem MidConvSystem = "mid_conv_system"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

    - `Role MessageParamRole`

      - `const MessageParamRoleUser MessageParamRole = "user"`

      - `const MessageParamRoleAssistant MessageParamRole = "assistant"`

      - `const MessageParamRoleSystem MessageParamRole = "system"`

  - `Model param.Field[Model]`

    The model that will complete your prompt.

    See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

  - `CacheControl param.Field[CacheControlEphemeral]`

    Top-level cache control automatically applies a cache_control marker to the last cacheable block in the request.

  - `Container param.Field[string]`

    Container identifier for reuse across requests.

  - `InferenceGeo param.Field[string]`

    Specifies the geographic region for inference processing. If not specified, the workspace's `default_inference_geo` is used.

  - `Metadata param.Field[Metadata]`

    An object describing metadata about the request.

  - `OutputConfig param.Field[OutputConfig]`

    Configuration options for the model's output, such as the output format.

  - `ServiceTier param.Field[MessageNewParamsServiceTier]`

    Determines whether to use priority capacity (if available) or standard capacity for this request.

    Anthropic offers different levels of service for your API requests. See [service-tiers](https://docs.claude.com/en/api/service-tiers) for details.

    - `const MessageNewParamsServiceTierAuto MessageNewParamsServiceTier = "auto"`

    - `const MessageNewParamsServiceTierStandardOnly MessageNewParamsServiceTier = "standard_only"`

  - `StopSequences param.Field[[]string]`

    Custom text sequences that will cause the model to stop generating.

    Our models will normally stop when they have naturally completed their turn, which will result in a response `stop_reason` of `"end_turn"`.

    If you want the model to stop generating when it encounters custom strings of text, you can use the `stop_sequences` parameter. If the model encounters one of the custom sequences, the response `stop_reason` value will be `"stop_sequence"` and the response `stop_sequence` value will contain the matched stop sequence.

  - ``

  - `System param.Field[[]TextBlockParamResp]`

    System prompt.

    A system prompt is a way of providing context and instructions to Claude, such as specifying a particular goal or role. See our [guide to system prompts](https://docs.claude.com/en/docs/system-prompts).

    - `[]TextBlockParam`

      - `Text string`

      - `Type Text`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations []TextCitationParamUnionResp`

  - `Temperature param.Field[float64]`

    Amount of randomness injected into the response.

    Defaults to `1.0`. Ranges from `0.0` to `1.0`. Use `temperature` closer to `0.0` for analytical / multiple choice, and closer to `1.0` for creative and generative tasks.

    Note that even with `temperature` of `0.0`, the results will not be fully deterministic.

  - `Thinking param.Field[ThinkingConfigParamUnionResp]`

    Configuration for enabling Claude's extended thinking.

    When enabled, responses include `thinking` content blocks showing Claude's thinking process before the final answer. Requires a minimum budget of 1,024 tokens and counts towards your `max_tokens` limit.

    See [extended thinking](https://docs.claude.com/en/docs/build-with-claude/extended-thinking) for details.

  - `ToolChoice param.Field[ToolChoiceUnion]`

    How the model should use the provided tools. The model can use a specific tool, any available tool, decide by itself, or not use tools at all.

  - `Tools param.Field[[]ToolUnion]`

    Definitions of tools that the model may use.

    If you include `tools` in your API request, the model may return `tool_use` content blocks that represent the model's use of those tools. You can then run those tools using the tool input generated by the model and then optionally return results back to the model using `tool_result` content blocks.

    There are two types of tools: **client tools** and **server tools**. The behavior described below applies to client tools. For [server tools](https://docs.claude.com/en/docs/agents-and-tools/tool-use/overview#server-tools), see their individual documentation as each has its own behavior (e.g., the [web search tool](https://docs.claude.com/en/docs/agents-and-tools/tool-use/web-search-tool)).

    Each tool definition includes:

    * `name`: Name of the tool.
    * `description`: Optional, but strongly-recommended description of the tool.
    * `input_schema`: [JSON schema](https://json-schema.org/draft/2020-12) for the tool `input` shape that the model will produce in `tool_use` output content blocks.

    For example, if you defined `tools` as:

    ```json
    [
      {
        "name": "get_stock_price",
        "description": "Get the current stock price for a given ticker symbol.",
        "input_schema": {
          "type": "object",
          "properties": {
            "ticker": {
              "type": "string",
              "description": "The stock ticker symbol, e.g. AAPL for Apple Inc."
            }
          },
          "required": ["ticker"]
        }
      }
    ]
    ```

    And then asked the model "What's the S&P 500 at today?", the model might produce `tool_use` content blocks in the response like this:

    ```json
    [
      {
        "type": "tool_use",
        "id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
        "name": "get_stock_price",
        "input": { "ticker": "^GSPC" }
      }
    ]
    ```

    You might then run your `get_stock_price` tool with `{"ticker": "^GSPC"}` as an input, and return the following back to the model in a subsequent `user` message:

    ```json
    [
      {
        "type": "tool_result",
        "tool_use_id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
        "content": "259.75 USD"
      }
    ]
    ```

    Tools can be used for workflows that include running client-side tools and functions, or more generally whenever you want the model to produce a particular JSON structure of output.

    See our [guide](https://docs.claude.com/en/docs/tool-use) for more details.

    - `type Tool struct{…}`

      - `InputSchema ToolInputSchema`

        [JSON schema](https://json-schema.org/draft/2020-12) for this tool's input.

        This defines the shape of the `input` that your tool accepts and that the model will produce.

        - `Type Object`

          - `const ObjectObject Object = "object"`

        - `Properties map[string, any]`

        - `Required []string`

      - `Name string`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

      - `AllowedCallers []string`

        - `const ToolAllowedCallerDirect ToolAllowedCaller = "direct"`

        - `const ToolAllowedCallerCodeExecution20250825 ToolAllowedCaller = "code_execution_20250825"`

        - `const ToolAllowedCallerCodeExecution20260120 ToolAllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Description string`

        Description of what this tool does.

        Tool descriptions should be as detailed as possible. The more information that the model has about what the tool is and how to use it, the better it will perform. You can use natural language descriptions to reinforce important aspects of the tool input JSON schema.

      - `EagerInputStreaming bool`

        Enable eager input streaming for this tool. When true, tool input parameters will be streamed incrementally as they are generated, and types will be inferred on-the-fly rather than buffering the full JSON output. When false, streaming is disabled for this tool even if the fine-grained-tool-streaming beta is active. When null (default), uses the default behavior based on beta headers.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

      - `Type ToolType`

        - `const ToolTypeCustom ToolType = "custom"`

    - `type ToolBash20250124 struct{…}`

      - `Name Bash`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const BashBash Bash = "bash"`

      - `Type Bash20250124`

        - `const Bash20250124Bash20250124 Bash20250124 = "bash_20250124"`

      - `AllowedCallers []string`

        - `const ToolBash20250124AllowedCallerDirect ToolBash20250124AllowedCaller = "direct"`

        - `const ToolBash20250124AllowedCallerCodeExecution20250825 ToolBash20250124AllowedCaller = "code_execution_20250825"`

        - `const ToolBash20250124AllowedCallerCodeExecution20260120 ToolBash20250124AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type CodeExecutionTool20250522 struct{…}`

      - `Name CodeExecution`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

      - `Type CodeExecution20250522`

        - `const CodeExecution20250522CodeExecution20250522 CodeExecution20250522 = "code_execution_20250522"`

      - `AllowedCallers []string`

        - `const CodeExecutionTool20250522AllowedCallerDirect CodeExecutionTool20250522AllowedCaller = "direct"`

        - `const CodeExecutionTool20250522AllowedCallerCodeExecution20250825 CodeExecutionTool20250522AllowedCaller = "code_execution_20250825"`

        - `const CodeExecutionTool20250522AllowedCallerCodeExecution20260120 CodeExecutionTool20250522AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type CodeExecutionTool20250825 struct{…}`

      - `Name CodeExecution`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

      - `AllowedCallers []string`

        - `const CodeExecutionTool20250825AllowedCallerDirect CodeExecutionTool20250825AllowedCaller = "direct"`

        - `const CodeExecutionTool20250825AllowedCallerCodeExecution20250825 CodeExecutionTool20250825AllowedCaller = "code_execution_20250825"`

        - `const CodeExecutionTool20250825AllowedCallerCodeExecution20260120 CodeExecutionTool20250825AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type CodeExecutionTool20260120 struct{…}`

      Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

      - `Name CodeExecution`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

      - `AllowedCallers []string`

        - `const CodeExecutionTool20260120AllowedCallerDirect CodeExecutionTool20260120AllowedCaller = "direct"`

        - `const CodeExecutionTool20260120AllowedCallerCodeExecution20250825 CodeExecutionTool20260120AllowedCaller = "code_execution_20250825"`

        - `const CodeExecutionTool20260120AllowedCallerCodeExecution20260120 CodeExecutionTool20260120AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type MemoryTool20250818 struct{…}`

      - `Name Memory`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const MemoryMemory Memory = "memory"`

      - `Type Memory20250818`

        - `const Memory20250818Memory20250818 Memory20250818 = "memory_20250818"`

      - `AllowedCallers []string`

        - `const MemoryTool20250818AllowedCallerDirect MemoryTool20250818AllowedCaller = "direct"`

        - `const MemoryTool20250818AllowedCallerCodeExecution20250825 MemoryTool20250818AllowedCaller = "code_execution_20250825"`

        - `const MemoryTool20250818AllowedCallerCodeExecution20260120 MemoryTool20250818AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type ToolTextEditor20250124 struct{…}`

      - `Name StrReplaceEditor`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const StrReplaceEditorStrReplaceEditor StrReplaceEditor = "str_replace_editor"`

      - `Type TextEditor20250124`

        - `const TextEditor20250124TextEditor20250124 TextEditor20250124 = "text_editor_20250124"`

      - `AllowedCallers []string`

        - `const ToolTextEditor20250124AllowedCallerDirect ToolTextEditor20250124AllowedCaller = "direct"`

        - `const ToolTextEditor20250124AllowedCallerCodeExecution20250825 ToolTextEditor20250124AllowedCaller = "code_execution_20250825"`

        - `const ToolTextEditor20250124AllowedCallerCodeExecution20260120 ToolTextEditor20250124AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type ToolTextEditor20250429 struct{…}`

      - `Name StrReplaceBasedEditTool`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

      - `Type TextEditor20250429`

        - `const TextEditor20250429TextEditor20250429 TextEditor20250429 = "text_editor_20250429"`

      - `AllowedCallers []string`

        - `const ToolTextEditor20250429AllowedCallerDirect ToolTextEditor20250429AllowedCaller = "direct"`

        - `const ToolTextEditor20250429AllowedCallerCodeExecution20250825 ToolTextEditor20250429AllowedCaller = "code_execution_20250825"`

        - `const ToolTextEditor20250429AllowedCallerCodeExecution20260120 ToolTextEditor20250429AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type ToolTextEditor20250728 struct{…}`

      - `Name StrReplaceBasedEditTool`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

      - `Type TextEditor20250728`

        - `const TextEditor20250728TextEditor20250728 TextEditor20250728 = "text_editor_20250728"`

      - `AllowedCallers []string`

        - `const ToolTextEditor20250728AllowedCallerDirect ToolTextEditor20250728AllowedCaller = "direct"`

        - `const ToolTextEditor20250728AllowedCallerCodeExecution20250825 ToolTextEditor20250728AllowedCaller = "code_execution_20250825"`

        - `const ToolTextEditor20250728AllowedCallerCodeExecution20260120 ToolTextEditor20250728AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `MaxCharacters int64`

        Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type WebSearchTool20250305 struct{…}`

      - `Name WebSearch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebSearchWebSearch WebSearch = "web_search"`

      - `Type WebSearch20250305`

        - `const WebSearch20250305WebSearch20250305 WebSearch20250305 = "web_search_20250305"`

      - `AllowedCallers []string`

        - `const WebSearchTool20250305AllowedCallerDirect WebSearchTool20250305AllowedCaller = "direct"`

        - `const WebSearchTool20250305AllowedCallerCodeExecution20250825 WebSearchTool20250305AllowedCaller = "code_execution_20250825"`

        - `const WebSearchTool20250305AllowedCallerCodeExecution20260120 WebSearchTool20250305AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

      - `BlockedDomains []string`

        If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

      - `UserLocation UserLocation`

        Parameters for the user's location. Used to provide more relevant search results.

        - `Type Approximate`

          - `const ApproximateApproximate Approximate = "approximate"`

        - `City string`

          The city of the user.

        - `Country string`

          The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user.

        - `Region string`

          The region of the user.

        - `Timezone string`

          The [IANA timezone](https://nodatime.org/TimeZones) of the user.

    - `type WebFetchTool20250910 struct{…}`

      - `Name WebFetch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebFetchWebFetch WebFetch = "web_fetch"`

      - `Type WebFetch20250910`

        - `const WebFetch20250910WebFetch20250910 WebFetch20250910 = "web_fetch_20250910"`

      - `AllowedCallers []string`

        - `const WebFetchTool20250910AllowedCallerDirect WebFetchTool20250910AllowedCaller = "direct"`

        - `const WebFetchTool20250910AllowedCallerCodeExecution20250825 WebFetchTool20250910AllowedCaller = "code_execution_20250825"`

        - `const WebFetchTool20250910AllowedCallerCodeExecution20260120 WebFetchTool20250910AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        List of domains to allow fetching from

      - `BlockedDomains []string`

        List of domains to block fetching from

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations CitationsConfigParamResp`

        Citations configuration for fetched documents. Citations are disabled by default.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxContentTokens int64`

        Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type WebSearchTool20260209 struct{…}`

      - `Name WebSearch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebSearchWebSearch WebSearch = "web_search"`

      - `Type WebSearch20260209`

        - `const WebSearch20260209WebSearch20260209 WebSearch20260209 = "web_search_20260209"`

      - `AllowedCallers []string`

        - `const WebSearchTool20260209AllowedCallerDirect WebSearchTool20260209AllowedCaller = "direct"`

        - `const WebSearchTool20260209AllowedCallerCodeExecution20250825 WebSearchTool20260209AllowedCaller = "code_execution_20250825"`

        - `const WebSearchTool20260209AllowedCallerCodeExecution20260120 WebSearchTool20260209AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

      - `BlockedDomains []string`

        If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

      - `UserLocation UserLocation`

        Parameters for the user's location. Used to provide more relevant search results.

    - `type WebFetchTool20260209 struct{…}`

      - `Name WebFetch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebFetchWebFetch WebFetch = "web_fetch"`

      - `Type WebFetch20260209`

        - `const WebFetch20260209WebFetch20260209 WebFetch20260209 = "web_fetch_20260209"`

      - `AllowedCallers []string`

        - `const WebFetchTool20260209AllowedCallerDirect WebFetchTool20260209AllowedCaller = "direct"`

        - `const WebFetchTool20260209AllowedCallerCodeExecution20250825 WebFetchTool20260209AllowedCaller = "code_execution_20250825"`

        - `const WebFetchTool20260209AllowedCallerCodeExecution20260120 WebFetchTool20260209AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        List of domains to allow fetching from

      - `BlockedDomains []string`

        List of domains to block fetching from

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations CitationsConfigParamResp`

        Citations configuration for fetched documents. Citations are disabled by default.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxContentTokens int64`

        Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type WebFetchTool20260309 struct{…}`

      Web fetch tool with use_cache parameter for bypassing cached content.

      - `Name WebFetch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebFetchWebFetch WebFetch = "web_fetch"`

      - `Type WebFetch20260309`

        - `const WebFetch20260309WebFetch20260309 WebFetch20260309 = "web_fetch_20260309"`

      - `AllowedCallers []string`

        - `const WebFetchTool20260309AllowedCallerDirect WebFetchTool20260309AllowedCaller = "direct"`

        - `const WebFetchTool20260309AllowedCallerCodeExecution20250825 WebFetchTool20260309AllowedCaller = "code_execution_20250825"`

        - `const WebFetchTool20260309AllowedCallerCodeExecution20260120 WebFetchTool20260309AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        List of domains to allow fetching from

      - `BlockedDomains []string`

        List of domains to block fetching from

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations CitationsConfigParamResp`

        Citations configuration for fetched documents. Citations are disabled by default.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxContentTokens int64`

        Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

      - `UseCache bool`

        Whether to use cached content. Set to false to bypass the cache and fetch fresh content. Only set to false when the user explicitly requests fresh content or when fetching rapidly-changing sources.

    - `type ToolSearchToolBm25_20251119 struct{…}`

      - `Name ToolSearchToolBm25`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const ToolSearchToolBm25ToolSearchToolBm25 ToolSearchToolBm25 = "tool_search_tool_bm25"`

      - `Type ToolSearchToolBm25_20251119Type`

        - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25_20251119 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25_20251119"`

        - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25"`

      - `AllowedCallers []string`

        - `const ToolSearchToolBm25_20251119AllowedCallerDirect ToolSearchToolBm25_20251119AllowedCaller = "direct"`

        - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20250825 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20250825"`

        - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20260120 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type ToolSearchToolRegex20251119 struct{…}`

      - `Name ToolSearchToolRegex`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const ToolSearchToolRegexToolSearchToolRegex ToolSearchToolRegex = "tool_search_tool_regex"`

      - `Type ToolSearchToolRegex20251119Type`

        - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex20251119 ToolSearchToolRegex20251119Type = "tool_search_tool_regex_20251119"`

        - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex ToolSearchToolRegex20251119Type = "tool_search_tool_regex"`

      - `AllowedCallers []string`

        - `const ToolSearchToolRegex20251119AllowedCallerDirect ToolSearchToolRegex20251119AllowedCaller = "direct"`

        - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20250825 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20250825"`

        - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20260120 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

  - `TopK param.Field[int64]`

    Only sample from the top K options for each subsequent token.

    Used to remove "long tail" low probability responses. [Learn more technical details here](https://towardsdatascience.com/how-to-sample-from-language-models-682bceb97277).

    Recommended for advanced use cases only.

  - `TopP param.Field[float64]`

    Use nucleus sampling.

    In nucleus sampling, we compute the cumulative distribution over all the options for each subsequent token in decreasing probability order and cut it off once it reaches a particular probability specified by `top_p`.

    Recommended for advanced use cases only.

### Returns

- `type Message struct{…}`

  - `ID string`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `Container Container`

    Information about the container used in the request (for the code execution tool)

    - `ID string`

      Identifier for the container used in this request

    - `ExpiresAt Time`

      The time at which the container will expire.

  - `Content []ContentBlockUnion`

    Content generated by the model.

    This is an array of content blocks, each of which has a `type` that determines its shape.

    Example:

    ```json
    [{"type": "text", "text": "Hi, I'm Claude."}]
    ```

    If the request input `messages` ended with an `assistant` turn, then the response `content` will continue directly from that last turn. You can use this to constrain the model's output.

    For example, if the input `messages` were:

    ```json
    [
      {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
      {"role": "assistant", "content": "The best answer is ("}
    ]
    ```

    Then the response `content` might be:

    ```json
    [{"type": "text", "text": "B)"}]
    ```

    - `type TextBlock struct{…}`

      - `Citations []TextCitationUnion`

        Citations supporting the text block.

        The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

        - `type CitationCharLocation struct{…}`

          - `CitedText string`

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndCharIndex int64`

          - `FileID string`

          - `StartCharIndex int64`

          - `Type CharLocation`

            - `const CharLocationCharLocation CharLocation = "char_location"`

        - `type CitationPageLocation struct{…}`

          - `CitedText string`

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndPageNumber int64`

          - `FileID string`

          - `StartPageNumber int64`

          - `Type PageLocation`

            - `const PageLocationPageLocation PageLocation = "page_location"`

        - `type CitationContentBlockLocation struct{…}`

          - `CitedText string`

            The full text of the cited block range, concatenated.

            Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndBlockIndex int64`

            Exclusive 0-based end index of the cited block range in the source's `content` array.

            Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

          - `FileID string`

          - `StartBlockIndex int64`

            0-based index of the first cited block in the source's `content` array.

          - `Type ContentBlockLocation`

            - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

        - `type CitationsWebSearchResultLocation struct{…}`

          - `CitedText string`

          - `EncryptedIndex string`

          - `Title string`

          - `Type WebSearchResultLocation`

            - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

          - `URL string`

        - `type CitationsSearchResultLocation struct{…}`

          - `CitedText string`

            The full text of the cited block range, concatenated.

            Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

          - `EndBlockIndex int64`

            Exclusive 0-based end index of the cited block range in the source's `content` array.

            Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

          - `SearchResultIndex int64`

            0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

            Counted separately from `document_index`; server-side web search results are not included in this count.

          - `Source string`

          - `StartBlockIndex int64`

            0-based index of the first cited block in the source's `content` array.

          - `Title string`

          - `Type SearchResultLocation`

            - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

      - `Text string`

      - `Type Text`

        - `const TextText Text = "text"`

    - `type ThinkingBlock struct{…}`

      - `Signature string`

      - `Thinking string`

      - `Type Thinking`

        - `const ThinkingThinking Thinking = "thinking"`

    - `type RedactedThinkingBlock struct{…}`

      - `Data string`

      - `Type RedactedThinking`

        - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

    - `type ToolUseBlock struct{…}`

      - `ID string`

      - `Caller ToolUseBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

          - `Type Direct`

            - `const DirectDirect Direct = "direct"`

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

          - `ToolID string`

          - `Type CodeExecution20250825`

            - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

        - `type ServerToolCaller20260120 struct{…}`

          - `ToolID string`

          - `Type CodeExecution20260120`

            - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

      - `Input map[string, any]`

      - `Name string`

      - `Type ToolUse`

        - `const ToolUseToolUse ToolUse = "tool_use"`

    - `type ServerToolUseBlock struct{…}`

      - `ID string`

      - `Caller ServerToolUseBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

        - `type ServerToolCaller20260120 struct{…}`

      - `Input map[string, any]`

      - `Name ServerToolUseBlockName`

        - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

        - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

        - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

        - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

        - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

        - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

        - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

      - `Type ServerToolUse`

        - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

    - `type WebSearchToolResultBlock struct{…}`

      - `Caller WebSearchToolResultBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

        - `type ServerToolCaller20260120 struct{…}`

      - `Content WebSearchToolResultBlockContentUnion`

        - `type WebSearchToolResultError struct{…}`

          - `ErrorCode WebSearchToolResultErrorCode`

            - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

            - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

            - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

            - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

            - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

            - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

          - `Type WebSearchToolResultError`

            - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

        - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

          - `EncryptedContent string`

          - `PageAge string`

          - `Title string`

          - `Type WebSearchResult`

            - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

          - `URL string`

      - `ToolUseID string`

      - `Type WebSearchToolResult`

        - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

    - `type WebFetchToolResultBlock struct{…}`

      - `Caller WebFetchToolResultBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

        - `type ServerToolCaller20260120 struct{…}`

      - `Content WebFetchToolResultBlockContentUnion`

        - `type WebFetchToolResultErrorBlock struct{…}`

          - `ErrorCode WebFetchToolResultErrorCode`

            - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

            - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

            - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

            - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

            - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

            - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

            - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

            - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

            - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

          - `Type WebFetchToolResultError`

            - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

        - `type WebFetchBlock struct{…}`

          - `Content DocumentBlock`

            - `Citations CitationsConfig`

              Citation configuration for the document

              - `Enabled bool`

            - `Source DocumentBlockSourceUnion`

              - `type Base64PDFSource struct{…}`

                - `Data string`

                - `MediaType ApplicationPDF`

                  - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                - `Type Base64`

                  - `const Base64Base64 Base64 = "base64"`

              - `type PlainTextSource struct{…}`

                - `Data string`

                - `MediaType TextPlain`

                  - `const TextPlainTextPlain TextPlain = "text/plain"`

                - `Type Text`

                  - `const TextText Text = "text"`

            - `Title string`

              The title of the document

            - `Type Document`

              - `const DocumentDocument Document = "document"`

          - `RetrievedAt string`

            ISO 8601 timestamp when the content was retrieved

          - `Type WebFetchResult`

            - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

          - `URL string`

            Fetched content URL

      - `ToolUseID string`

      - `Type WebFetchToolResult`

        - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

    - `type CodeExecutionToolResultBlock struct{…}`

      - `Content CodeExecutionToolResultBlockContentUnion`

        Code execution result with encrypted stdout for PFC + web_search results.

        - `type CodeExecutionToolResultError struct{…}`

          - `ErrorCode CodeExecutionToolResultErrorCode`

            - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

            - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

            - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

            - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

          - `Type CodeExecutionToolResultError`

            - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

        - `type CodeExecutionResultBlock struct{…}`

          - `Content []CodeExecutionOutputBlock`

            - `FileID string`

            - `Type CodeExecutionOutput`

              - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

          - `ReturnCode int64`

          - `Stderr string`

          - `Stdout string`

          - `Type CodeExecutionResult`

            - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

        - `type EncryptedCodeExecutionResultBlock struct{…}`

          Code execution result with encrypted stdout for PFC + web_search results.

          - `Content []CodeExecutionOutputBlock`

            - `FileID string`

            - `Type CodeExecutionOutput`

          - `EncryptedStdout string`

          - `ReturnCode int64`

          - `Stderr string`

          - `Type EncryptedCodeExecutionResult`

            - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

      - `ToolUseID string`

      - `Type CodeExecutionToolResult`

        - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

    - `type BashCodeExecutionToolResultBlock struct{…}`

      - `Content BashCodeExecutionToolResultBlockContentUnion`

        - `type BashCodeExecutionToolResultError struct{…}`

          - `ErrorCode BashCodeExecutionToolResultErrorCode`

            - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

            - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

            - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

            - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

            - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

          - `Type BashCodeExecutionToolResultError`

            - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

        - `type BashCodeExecutionResultBlock struct{…}`

          - `Content []BashCodeExecutionOutputBlock`

            - `FileID string`

            - `Type BashCodeExecutionOutput`

              - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

          - `ReturnCode int64`

          - `Stderr string`

          - `Stdout string`

          - `Type BashCodeExecutionResult`

            - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

      - `ToolUseID string`

      - `Type BashCodeExecutionToolResult`

        - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

    - `type TextEditorCodeExecutionToolResultBlock struct{…}`

      - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

        - `type TextEditorCodeExecutionToolResultError struct{…}`

          - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

            - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

            - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

            - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

            - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

            - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

          - `ErrorMessage string`

          - `Type TextEditorCodeExecutionToolResultError`

            - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

        - `type TextEditorCodeExecutionViewResultBlock struct{…}`

          - `Content string`

          - `FileType TextEditorCodeExecutionViewResultBlockFileType`

            - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

            - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

            - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

          - `NumLines int64`

          - `StartLine int64`

          - `TotalLines int64`

          - `Type TextEditorCodeExecutionViewResult`

            - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

        - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

          - `IsFileUpdate bool`

          - `Type TextEditorCodeExecutionCreateResult`

            - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

        - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

          - `Lines []string`

          - `NewLines int64`

          - `NewStart int64`

          - `OldLines int64`

          - `OldStart int64`

          - `Type TextEditorCodeExecutionStrReplaceResult`

            - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

      - `ToolUseID string`

      - `Type TextEditorCodeExecutionToolResult`

        - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

    - `type ToolSearchToolResultBlock struct{…}`

      - `Content ToolSearchToolResultBlockContentUnion`

        - `type ToolSearchToolResultError struct{…}`

          - `ErrorCode ToolSearchToolResultErrorCode`

            - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

            - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

            - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

            - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

          - `ErrorMessage string`

          - `Type ToolSearchToolResultError`

            - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

        - `type ToolSearchToolSearchResultBlock struct{…}`

          - `ToolReferences []ToolReferenceBlock`

            - `ToolName string`

            - `Type ToolReference`

              - `const ToolReferenceToolReference ToolReference = "tool_reference"`

          - `Type ToolSearchToolSearchResult`

            - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

      - `ToolUseID string`

      - `Type ToolSearchToolResult`

        - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

    - `type ContainerUploadBlock struct{…}`

      Response model for a file uploaded to the container.

      - `FileID string`

      - `Type ContainerUpload`

        - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

  - `Model Model`

    The model that will complete your prompt.

    See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

    - `type Model string`

      The model that will complete your prompt.

      See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

      - `const ModelClaudeFable5 Model = "claude-fable-5"`

        Next generation of intelligence for the hardest knowledge work and coding problems

      - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

        Most capable model for cybersecurity and biology research

      - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

        Frontier intelligence for long-running agents and coding

      - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

        Frontier intelligence for long-running agents and coding

      - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

        New class of intelligence, strongest in coding and cybersecurity

      - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

        Frontier intelligence for long-running agents and coding

      - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

        Best combination of speed and intelligence

      - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

        Fastest model with near-frontier intelligence

      - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

        Fastest model with near-frontier intelligence

      - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

        Premium model combining maximum intelligence with practical performance

      - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

        Premium model combining maximum intelligence with practical performance

      - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

        High-performance model for agents and coding

      - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

        High-performance model for agents and coding

      - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

        Exceptional model for specialized complex tasks

      - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

        Exceptional model for specialized complex tasks

      - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

        Powerful model for complex tasks

      - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

        Powerful model for complex tasks

      - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

        High-performance model with extended thinking

      - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

        High-performance model with extended thinking

      - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

        Fast and cost-effective model

    - `string`

  - `Role Assistant`

    Conversational role of the generated message.

    This will always be `"assistant"`.

    - `const AssistantAssistant Assistant = "assistant"`

  - `StopDetails RefusalStopDetails`

    Structured information about a refusal.

    - `Category RefusalStopDetailsCategory`

      The policy category that triggered the refusal.

      `null` when the refusal doesn't map to a named category.

      - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

      - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

      - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

    - `Explanation string`

      Human-readable explanation of the refusal.

      This text is not guaranteed to be stable. `null` when no explanation is available for the category.

    - `Type Refusal`

      - `const RefusalRefusal Refusal = "refusal"`

  - `StopReason StopReason`

    The reason that we stopped.

    This may be one the following values:

    * `"end_turn"`: the model reached a natural stopping point
    * `"max_tokens"`: we exceeded the requested `max_tokens` or the model's maximum
    * `"stop_sequence"`: one of your provided custom `stop_sequences` was generated
    * `"tool_use"`: the model invoked one or more tools
    * `"pause_turn"`: we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
    * `"refusal"`: when streaming classifiers intervene to handle potential policy violations

    In non-streaming mode this value is always non-null. In streaming mode, it is null in the `message_start` event and non-null otherwise.

    - `const StopReasonEndTurn StopReason = "end_turn"`

    - `const StopReasonMaxTokens StopReason = "max_tokens"`

    - `const StopReasonStopSequence StopReason = "stop_sequence"`

    - `const StopReasonToolUse StopReason = "tool_use"`

    - `const StopReasonPauseTurn StopReason = "pause_turn"`

    - `const StopReasonRefusal StopReason = "refusal"`

  - `StopSequence string`

    Which custom stop sequence was generated, if any.

    This value will be a non-null string if one of your custom stop sequences was generated.

  - `Type Message`

    Object type.

    For Messages, this is always `"message"`.

    - `const MessageMessage Message = "message"`

  - `Usage Usage`

    Billing and rate-limit usage.

    Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

    Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

    For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

    Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

    - `CacheCreation CacheCreation`

      Breakdown of cached tokens by TTL

      - `Ephemeral1hInputTokens int64`

        The number of input tokens used to create the 1 hour cache entry.

      - `Ephemeral5mInputTokens int64`

        The number of input tokens used to create the 5 minute cache entry.

    - `CacheCreationInputTokens int64`

      The number of input tokens used to create the cache entry.

    - `CacheReadInputTokens int64`

      The number of input tokens read from the cache.

    - `InferenceGeo string`

      The geographic region where inference was performed for this request.

    - `InputTokens int64`

      The number of input tokens which were used.

    - `OutputTokens int64`

      The number of output tokens which were used.

    - `OutputTokensDetails OutputTokensDetails`

      Breakdown of output tokens by category.

      `output_tokens` remains the inclusive, authoritative total used for billing.
      This object provides a read-only decomposition for observability — for example,
      how many of the billed output tokens were spent on internal reasoning that may
      have been summarized before being returned to you.

      - `ThinkingTokens int64`

        Number of output tokens the model generated as internal reasoning, including
        the thinking-block delimiter tokens.

        Reflects the raw reasoning the model produced, not the (possibly shorter)
        summarized thinking text returned in the response body. Computed by
        re-tokenizing the raw reasoning text, so it may differ from the model's exact
        generation count by a small number of tokens. Always ≤ `output_tokens`;
        `output_tokens - thinking_tokens` approximates the non-reasoning output.

    - `ServerToolUse ServerToolUsage`

      The number of server tool requests.

      - `WebFetchRequests int64`

        The number of web fetch tool requests.

      - `WebSearchRequests int64`

        The number of web search tool requests.

    - `ServiceTier UsageServiceTier`

      If the request used the priority, standard, or batch tier.

      - `const UsageServiceTierStandard UsageServiceTier = "standard"`

      - `const UsageServiceTierPriority UsageServiceTier = "priority"`

      - `const UsageServiceTierBatch UsageServiceTier = "batch"`

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/anthropics/anthropic-sdk-go"
  "github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
  client := anthropic.NewClient(
    option.WithAPIKey("my-anthropic-api-key"),
  )
  message, err := client.Messages.New(context.TODO(), anthropic.MessageNewParams{
    MaxTokens: 1024,
    Messages: []anthropic.MessageParam{anthropic.MessageParam{
      Content: []anthropic.ContentBlockParamUnion{anthropic.ContentBlockParamUnion{
        OfText: &anthropic.TextBlockParam{
          Text: "x",
        },
      }},
      Role: anthropic.MessageParamRoleUser,
    }},
    Model: anthropic.ModelClaudeOpus4_6,
  })
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", message.ID)
}
```

#### Response

```json
{
  "id": "msg_013Zva2CMHLNnXjNJJKqJ2EF",
  "container": {
    "id": "id",
    "expires_at": "2019-12-27T18:11:19.117Z"
  },
  "content": [
    {
      "citations": [
        {
          "cited_text": "cited_text",
          "document_index": 0,
          "document_title": "document_title",
          "end_char_index": 0,
          "file_id": "file_id",
          "start_char_index": 0,
          "type": "char_location"
        }
      ],
      "text": "Hi! My name is Claude.",
      "type": "text"
    }
  ],
  "model": "claude-opus-4-6",
  "role": "assistant",
  "stop_details": {
    "category": "cyber",
    "explanation": "explanation",
    "type": "refusal"
  },
  "stop_reason": "end_turn",
  "stop_sequence": null,
  "type": "message",
  "usage": {
    "cache_creation": {
      "ephemeral_1h_input_tokens": 0,
      "ephemeral_5m_input_tokens": 0
    },
    "cache_creation_input_tokens": 2051,
    "cache_read_input_tokens": 2051,
    "inference_geo": "inference_geo",
    "input_tokens": 2095,
    "output_tokens": 503,
    "output_tokens_details": {
      "thinking_tokens": 0
    },
    "server_tool_use": {
      "web_fetch_requests": 2,
      "web_search_requests": 0
    },
    "service_tier": "standard"
  }
}
```

## Count tokens in a Message

`client.Messages.CountTokens(ctx, body) (*MessageTokensCount, error)`

**post** `/v1/messages/count_tokens`

Count the number of tokens in a Message.

The Token Count API can be used to count the number of tokens in a Message, including tools, images, and documents, without creating it.

Learn more about token counting in our [user guide](https://docs.claude.com/en/docs/build-with-claude/token-counting)

### Parameters

- `body MessageCountTokensParams`

  - `Messages param.Field[[]MessageParamResp]`

    Input messages.

    Our models are trained to operate on alternating `user` and `assistant` conversational turns. When creating a new `Message`, you specify the prior conversational turns with the `messages` parameter, and the model then generates the next `Message` in the conversation. Consecutive `user` or `assistant` turns in your request will be combined into a single turn.

    Each input message must be an object with a `role` and `content`. You can specify a single `user`-role message, or you can include multiple `user` and `assistant` messages.

    If the final message uses the `assistant` role, the response content will continue immediately from the content in that message. This can be used to constrain part of the model's response.

    Example with a single `user` message:

    ```json
    [{"role": "user", "content": "Hello, Claude"}]
    ```

    Example with multiple conversational turns:

    ```json
    [
      {"role": "user", "content": "Hello there."},
      {"role": "assistant", "content": "Hi, I'm Claude. How can I help you?"},
      {"role": "user", "content": "Can you explain LLMs in plain English?"},
    ]
    ```

    Example with a partially-filled response from Claude:

    ```json
    [
      {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
      {"role": "assistant", "content": "The best answer is ("},
    ]
    ```

    Each input message `content` may be either a single `string` or an array of content blocks, where each block has a specific `type`. Using a `string` for `content` is shorthand for an array of one content block of type `"text"`. The following input messages are equivalent:

    ```json
    {"role": "user", "content": "Hello, Claude"}
    ```

    ```json
    {"role": "user", "content": [{"type": "text", "text": "Hello, Claude"}]}
    ```

    See [input examples](https://docs.claude.com/en/api/messages-examples).

    Note that if you want to include a [system prompt](https://docs.claude.com/en/docs/system-prompts), you can use the top-level `system` parameter — there is no `"system"` role for input messages in the Messages API.

    There is a limit of 100,000 messages in a single request.

    - `Content []ContentBlockParamUnionResp`

      - `[]ContentBlockParamUnionResp`

        - `type TextBlockParamResp struct{…}`

          - `Text string`

          - `Type Text`

            - `const TextText Text = "text"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

            - `Type Ephemeral`

              - `const EphemeralEphemeral Ephemeral = "ephemeral"`

            - `TTL CacheControlEphemeralTTL`

              The time-to-live for the cache control breakpoint.

              This may be one the following values:

              - `5m`: 5 minutes
              - `1h`: 1 hour

              Defaults to `5m`.

              - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

              - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

          - `Citations []TextCitationParamUnionResp`

            - `type CitationCharLocationParamResp struct{…}`

              - `CitedText string`

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndCharIndex int64`

              - `StartCharIndex int64`

              - `Type CharLocation`

                - `const CharLocationCharLocation CharLocation = "char_location"`

            - `type CitationPageLocationParamResp struct{…}`

              - `CitedText string`

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndPageNumber int64`

              - `StartPageNumber int64`

              - `Type PageLocation`

                - `const PageLocationPageLocation PageLocation = "page_location"`

            - `type CitationContentBlockLocationParamResp struct{…}`

              - `CitedText string`

                The full text of the cited block range, concatenated.

                Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndBlockIndex int64`

                Exclusive 0-based end index of the cited block range in the source's `content` array.

                Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

              - `StartBlockIndex int64`

                0-based index of the first cited block in the source's `content` array.

              - `Type ContentBlockLocation`

                - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

            - `type CitationWebSearchResultLocationParamResp struct{…}`

              - `CitedText string`

              - `EncryptedIndex string`

              - `Title string`

              - `Type WebSearchResultLocation`

                - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

              - `URL string`

            - `type CitationSearchResultLocationParamResp struct{…}`

              - `CitedText string`

                The full text of the cited block range, concatenated.

                Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

              - `EndBlockIndex int64`

                Exclusive 0-based end index of the cited block range in the source's `content` array.

                Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

              - `SearchResultIndex int64`

                0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                Counted separately from `document_index`; server-side web search results are not included in this count.

              - `Source string`

              - `StartBlockIndex int64`

                0-based index of the first cited block in the source's `content` array.

              - `Title string`

              - `Type SearchResultLocation`

                - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

        - `type ImageBlockParamResp struct{…}`

          - `Source ImageBlockParamSourceUnionResp`

            - `type Base64ImageSource struct{…}`

              - `Data string`

              - `MediaType Base64ImageSourceMediaType`

                - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

                - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

                - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

                - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

              - `Type Base64`

                - `const Base64Base64 Base64 = "base64"`

            - `type URLImageSource struct{…}`

              - `Type URL`

                - `const URLURL URL = "url"`

              - `URL string`

          - `Type Image`

            - `const ImageImage Image = "image"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type DocumentBlockParamResp struct{…}`

          - `Source DocumentBlockParamSourceUnionResp`

            - `type Base64PDFSource struct{…}`

              - `Data string`

              - `MediaType ApplicationPDF`

                - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

              - `Type Base64`

                - `const Base64Base64 Base64 = "base64"`

            - `type PlainTextSource struct{…}`

              - `Data string`

              - `MediaType TextPlain`

                - `const TextPlainTextPlain TextPlain = "text/plain"`

              - `Type Text`

                - `const TextText Text = "text"`

            - `type ContentBlockSource struct{…}`

              - `Content ContentBlockSourceContentUnion`

                - `string`

                - `[]ContentBlockSourceContentItemUnion`

                  - `type TextBlockParamResp struct{…}`

                  - `type ImageBlockParamResp struct{…}`

              - `Type Content`

                - `const ContentContent Content = "content"`

            - `type URLPDFSource struct{…}`

              - `Type URL`

                - `const URLURL URL = "url"`

              - `URL string`

          - `Type Document`

            - `const DocumentDocument Document = "document"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations CitationsConfigParamResp`

            - `Enabled bool`

          - `Context string`

          - `Title string`

        - `type SearchResultBlockParamResp struct{…}`

          - `Content []TextBlockParamResp`

            - `Text string`

            - `Type Text`

            - `CacheControl CacheControlEphemeral`

              Create a cache control breakpoint at this content block.

            - `Citations []TextCitationParamUnionResp`

          - `Source string`

          - `Title string`

          - `Type SearchResult`

            - `const SearchResultSearchResult SearchResult = "search_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations CitationsConfigParamResp`

        - `type ThinkingBlockParamResp struct{…}`

          - `Signature string`

          - `Thinking string`

          - `Type Thinking`

            - `const ThinkingThinking Thinking = "thinking"`

        - `type RedactedThinkingBlockParamResp struct{…}`

          - `Data string`

          - `Type RedactedThinking`

            - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

        - `type ToolUseBlockParamResp struct{…}`

          - `ID string`

          - `Input map[string, any]`

          - `Name string`

          - `Type ToolUse`

            - `const ToolUseToolUse ToolUse = "tool_use"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Caller ToolUseBlockParamCallerUnionResp`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

              - `Type Direct`

                - `const DirectDirect Direct = "direct"`

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

              - `ToolID string`

              - `Type CodeExecution20250825`

                - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

            - `type ServerToolCaller20260120 struct{…}`

              - `ToolID string`

              - `Type CodeExecution20260120`

                - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

        - `type ToolResultBlockParamResp struct{…}`

          - `ToolUseID string`

          - `Type ToolResult`

            - `const ToolResultToolResult ToolResult = "tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Content []ToolResultBlockParamContentUnionResp`

            - `[]ToolResultBlockParamContentUnionResp`

              - `type TextBlockParamResp struct{…}`

              - `type ImageBlockParamResp struct{…}`

              - `type SearchResultBlockParamResp struct{…}`

              - `type DocumentBlockParamResp struct{…}`

              - `type ToolReferenceBlockParamResp struct{…}`

                Tool reference block that can be included in tool_result content.

                - `ToolName string`

                - `Type ToolReference`

                  - `const ToolReferenceToolReference ToolReference = "tool_reference"`

                - `CacheControl CacheControlEphemeral`

                  Create a cache control breakpoint at this content block.

          - `IsError bool`

        - `type ServerToolUseBlockParamResp struct{…}`

          - `ID string`

          - `Input map[string, any]`

          - `Name ServerToolUseBlockParamName`

            - `const ServerToolUseBlockParamNameWebSearch ServerToolUseBlockParamName = "web_search"`

            - `const ServerToolUseBlockParamNameWebFetch ServerToolUseBlockParamName = "web_fetch"`

            - `const ServerToolUseBlockParamNameCodeExecution ServerToolUseBlockParamName = "code_execution"`

            - `const ServerToolUseBlockParamNameBashCodeExecution ServerToolUseBlockParamName = "bash_code_execution"`

            - `const ServerToolUseBlockParamNameTextEditorCodeExecution ServerToolUseBlockParamName = "text_editor_code_execution"`

            - `const ServerToolUseBlockParamNameToolSearchToolRegex ServerToolUseBlockParamName = "tool_search_tool_regex"`

            - `const ServerToolUseBlockParamNameToolSearchToolBm25 ServerToolUseBlockParamName = "tool_search_tool_bm25"`

          - `Type ServerToolUse`

            - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Caller ServerToolUseBlockParamCallerUnionResp`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

        - `type WebSearchToolResultBlockParamResp struct{…}`

          - `Content WebSearchToolResultBlockParamContentUnionResp`

            - `[]WebSearchResultBlockParamResp`

              - `EncryptedContent string`

              - `Title string`

              - `Type WebSearchResult`

                - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

              - `URL string`

              - `PageAge string`

            - `type WebSearchToolRequestError struct{…}`

              - `ErrorCode WebSearchToolResultErrorCode`

                - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

                - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

                - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

                - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

                - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

                - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

              - `Type WebSearchToolResultError`

                - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

          - `ToolUseID string`

          - `Type WebSearchToolResult`

            - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Caller WebSearchToolResultBlockParamCallerUnionResp`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

        - `type WebFetchToolResultBlockParamResp struct{…}`

          - `Content WebFetchToolResultBlockParamContentUnionResp`

            - `type WebFetchToolResultErrorBlockParamResp struct{…}`

              - `ErrorCode WebFetchToolResultErrorCode`

                - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

                - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

                - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

                - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

                - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

                - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

                - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

                - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

                - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

              - `Type WebFetchToolResultError`

                - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

            - `type WebFetchBlockParamResp struct{…}`

              - `Content DocumentBlockParamResp`

              - `Type WebFetchResult`

                - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

              - `URL string`

                Fetched content URL

              - `RetrievedAt string`

                ISO 8601 timestamp when the content was retrieved

          - `ToolUseID string`

          - `Type WebFetchToolResult`

            - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Caller WebFetchToolResultBlockParamCallerUnionResp`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

        - `type CodeExecutionToolResultBlockParamResp struct{…}`

          - `Content CodeExecutionToolResultBlockParamContentUnionResp`

            Code execution result with encrypted stdout for PFC + web_search results.

            - `type CodeExecutionToolResultErrorParamResp struct{…}`

              - `ErrorCode CodeExecutionToolResultErrorCode`

                - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

                - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `Type CodeExecutionToolResultError`

                - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

            - `type CodeExecutionResultBlockParamResp struct{…}`

              - `Content []CodeExecutionOutputBlockParamResp`

                - `FileID string`

                - `Type CodeExecutionOutput`

                  - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

              - `ReturnCode int64`

              - `Stderr string`

              - `Stdout string`

              - `Type CodeExecutionResult`

                - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

            - `type EncryptedCodeExecutionResultBlockParamResp struct{…}`

              Code execution result with encrypted stdout for PFC + web_search results.

              - `Content []CodeExecutionOutputBlockParamResp`

                - `FileID string`

                - `Type CodeExecutionOutput`

              - `EncryptedStdout string`

              - `ReturnCode int64`

              - `Stderr string`

              - `Type EncryptedCodeExecutionResult`

                - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

          - `ToolUseID string`

          - `Type CodeExecutionToolResult`

            - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type BashCodeExecutionToolResultBlockParamResp struct{…}`

          - `Content BashCodeExecutionToolResultBlockParamContentUnionResp`

            - `type BashCodeExecutionToolResultErrorParamResp struct{…}`

              - `ErrorCode BashCodeExecutionToolResultErrorCode`

                - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

                - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

              - `Type BashCodeExecutionToolResultError`

                - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

            - `type BashCodeExecutionResultBlockParamResp struct{…}`

              - `Content []BashCodeExecutionOutputBlockParamResp`

                - `FileID string`

                - `Type BashCodeExecutionOutput`

                  - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

              - `ReturnCode int64`

              - `Stderr string`

              - `Stdout string`

              - `Type BashCodeExecutionResult`

                - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

          - `ToolUseID string`

          - `Type BashCodeExecutionToolResult`

            - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type TextEditorCodeExecutionToolResultBlockParamResp struct{…}`

          - `Content TextEditorCodeExecutionToolResultBlockParamContentUnionResp`

            - `type TextEditorCodeExecutionToolResultErrorParamResp struct{…}`

              - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

                - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

                - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

              - `Type TextEditorCodeExecutionToolResultError`

                - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

              - `ErrorMessage string`

            - `type TextEditorCodeExecutionViewResultBlockParamResp struct{…}`

              - `Content string`

              - `FileType TextEditorCodeExecutionViewResultBlockParamFileType`

                - `const TextEditorCodeExecutionViewResultBlockParamFileTypeText TextEditorCodeExecutionViewResultBlockParamFileType = "text"`

                - `const TextEditorCodeExecutionViewResultBlockParamFileTypeImage TextEditorCodeExecutionViewResultBlockParamFileType = "image"`

                - `const TextEditorCodeExecutionViewResultBlockParamFileTypePDF TextEditorCodeExecutionViewResultBlockParamFileType = "pdf"`

              - `Type TextEditorCodeExecutionViewResult`

                - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

              - `NumLines int64`

              - `StartLine int64`

              - `TotalLines int64`

            - `type TextEditorCodeExecutionCreateResultBlockParamResp struct{…}`

              - `IsFileUpdate bool`

              - `Type TextEditorCodeExecutionCreateResult`

                - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

            - `type TextEditorCodeExecutionStrReplaceResultBlockParamResp struct{…}`

              - `Type TextEditorCodeExecutionStrReplaceResult`

                - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

              - `Lines []string`

              - `NewLines int64`

              - `NewStart int64`

              - `OldLines int64`

              - `OldStart int64`

          - `ToolUseID string`

          - `Type TextEditorCodeExecutionToolResult`

            - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type ToolSearchToolResultBlockParamResp struct{…}`

          - `Content ToolSearchToolResultBlockParamContentUnionResp`

            - `type ToolSearchToolResultErrorParamResp struct{…}`

              - `ErrorCode ToolSearchToolResultErrorCode`

                - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

                - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

                - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

                - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

              - `Type ToolSearchToolResultError`

                - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

              - `ErrorMessage string`

            - `type ToolSearchToolSearchResultBlockParamResp struct{…}`

              - `ToolReferences []ToolReferenceBlockParamResp`

                - `ToolName string`

                - `Type ToolReference`

                - `CacheControl CacheControlEphemeral`

                  Create a cache control breakpoint at this content block.

              - `Type ToolSearchToolSearchResult`

                - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

          - `ToolUseID string`

          - `Type ToolSearchToolResult`

            - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type ContainerUploadBlockParamResp struct{…}`

          A content block that represents a file to be uploaded to the container
          Files uploaded via this block will be available in the container's input directory.

          - `FileID string`

          - `Type ContainerUpload`

            - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `type MidConversationSystemBlockParamResp struct{…}`

          System instructions that appear mid-conversation.

          Use this block to provide or update system-level instructions at a specific
          point in the conversation, rather than only via the top-level `system` parameter.

          - `Content []TextBlockParamResp`

            System instruction text blocks.

            - `Text string`

            - `Type Text`

            - `CacheControl CacheControlEphemeral`

              Create a cache control breakpoint at this content block.

            - `Citations []TextCitationParamUnionResp`

          - `Type MidConvSystem`

            - `const MidConvSystemMidConvSystem MidConvSystem = "mid_conv_system"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

    - `Role MessageParamRole`

      - `const MessageParamRoleUser MessageParamRole = "user"`

      - `const MessageParamRoleAssistant MessageParamRole = "assistant"`

      - `const MessageParamRoleSystem MessageParamRole = "system"`

  - `Model param.Field[Model]`

    The model that will complete your prompt.

    See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

  - `CacheControl param.Field[CacheControlEphemeral]`

    Top-level cache control automatically applies a cache_control marker to the last cacheable block in the request.

  - `OutputConfig param.Field[OutputConfig]`

    Configuration options for the model's output, such as the output format.

  - `System param.Field[MessageCountTokensParamsSystemUnion]`

    System prompt.

    A system prompt is a way of providing context and instructions to Claude, such as specifying a particular goal or role. See our [guide to system prompts](https://docs.claude.com/en/docs/system-prompts).

    - `string`

    - `type MessageCountTokensParamsSystemArray []TextBlockParamResp`

      - `Text string`

      - `Type Text`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations []TextCitationParamUnionResp`

  - `Thinking param.Field[ThinkingConfigParamUnionResp]`

    Configuration for enabling Claude's extended thinking.

    When enabled, responses include `thinking` content blocks showing Claude's thinking process before the final answer. Requires a minimum budget of 1,024 tokens and counts towards your `max_tokens` limit.

    See [extended thinking](https://docs.claude.com/en/docs/build-with-claude/extended-thinking) for details.

  - `ToolChoice param.Field[ToolChoiceUnion]`

    How the model should use the provided tools. The model can use a specific tool, any available tool, decide by itself, or not use tools at all.

  - `Tools param.Field[[]MessageCountTokensToolUnion]`

    Definitions of tools that the model may use.

    If you include `tools` in your API request, the model may return `tool_use` content blocks that represent the model's use of those tools. You can then run those tools using the tool input generated by the model and then optionally return results back to the model using `tool_result` content blocks.

    There are two types of tools: **client tools** and **server tools**. The behavior described below applies to client tools. For [server tools](https://docs.claude.com/en/docs/agents-and-tools/tool-use/overview#server-tools), see their individual documentation as each has its own behavior (e.g., the [web search tool](https://docs.claude.com/en/docs/agents-and-tools/tool-use/web-search-tool)).

    Each tool definition includes:

    * `name`: Name of the tool.
    * `description`: Optional, but strongly-recommended description of the tool.
    * `input_schema`: [JSON schema](https://json-schema.org/draft/2020-12) for the tool `input` shape that the model will produce in `tool_use` output content blocks.

    For example, if you defined `tools` as:

    ```json
    [
      {
        "name": "get_stock_price",
        "description": "Get the current stock price for a given ticker symbol.",
        "input_schema": {
          "type": "object",
          "properties": {
            "ticker": {
              "type": "string",
              "description": "The stock ticker symbol, e.g. AAPL for Apple Inc."
            }
          },
          "required": ["ticker"]
        }
      }
    ]
    ```

    And then asked the model "What's the S&P 500 at today?", the model might produce `tool_use` content blocks in the response like this:

    ```json
    [
      {
        "type": "tool_use",
        "id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
        "name": "get_stock_price",
        "input": { "ticker": "^GSPC" }
      }
    ]
    ```

    You might then run your `get_stock_price` tool with `{"ticker": "^GSPC"}` as an input, and return the following back to the model in a subsequent `user` message:

    ```json
    [
      {
        "type": "tool_result",
        "tool_use_id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
        "content": "259.75 USD"
      }
    ]
    ```

    Tools can be used for workflows that include running client-side tools and functions, or more generally whenever you want the model to produce a particular JSON structure of output.

    See our [guide](https://docs.claude.com/en/docs/tool-use) for more details.

    - `type Tool struct{…}`

      - `InputSchema ToolInputSchema`

        [JSON schema](https://json-schema.org/draft/2020-12) for this tool's input.

        This defines the shape of the `input` that your tool accepts and that the model will produce.

        - `Type Object`

          - `const ObjectObject Object = "object"`

        - `Properties map[string, any]`

        - `Required []string`

      - `Name string`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

      - `AllowedCallers []string`

        - `const ToolAllowedCallerDirect ToolAllowedCaller = "direct"`

        - `const ToolAllowedCallerCodeExecution20250825 ToolAllowedCaller = "code_execution_20250825"`

        - `const ToolAllowedCallerCodeExecution20260120 ToolAllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Description string`

        Description of what this tool does.

        Tool descriptions should be as detailed as possible. The more information that the model has about what the tool is and how to use it, the better it will perform. You can use natural language descriptions to reinforce important aspects of the tool input JSON schema.

      - `EagerInputStreaming bool`

        Enable eager input streaming for this tool. When true, tool input parameters will be streamed incrementally as they are generated, and types will be inferred on-the-fly rather than buffering the full JSON output. When false, streaming is disabled for this tool even if the fine-grained-tool-streaming beta is active. When null (default), uses the default behavior based on beta headers.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

      - `Type ToolType`

        - `const ToolTypeCustom ToolType = "custom"`

    - `type ToolBash20250124 struct{…}`

      - `Name Bash`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const BashBash Bash = "bash"`

      - `Type Bash20250124`

        - `const Bash20250124Bash20250124 Bash20250124 = "bash_20250124"`

      - `AllowedCallers []string`

        - `const ToolBash20250124AllowedCallerDirect ToolBash20250124AllowedCaller = "direct"`

        - `const ToolBash20250124AllowedCallerCodeExecution20250825 ToolBash20250124AllowedCaller = "code_execution_20250825"`

        - `const ToolBash20250124AllowedCallerCodeExecution20260120 ToolBash20250124AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type CodeExecutionTool20250522 struct{…}`

      - `Name CodeExecution`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

      - `Type CodeExecution20250522`

        - `const CodeExecution20250522CodeExecution20250522 CodeExecution20250522 = "code_execution_20250522"`

      - `AllowedCallers []string`

        - `const CodeExecutionTool20250522AllowedCallerDirect CodeExecutionTool20250522AllowedCaller = "direct"`

        - `const CodeExecutionTool20250522AllowedCallerCodeExecution20250825 CodeExecutionTool20250522AllowedCaller = "code_execution_20250825"`

        - `const CodeExecutionTool20250522AllowedCallerCodeExecution20260120 CodeExecutionTool20250522AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type CodeExecutionTool20250825 struct{…}`

      - `Name CodeExecution`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

      - `AllowedCallers []string`

        - `const CodeExecutionTool20250825AllowedCallerDirect CodeExecutionTool20250825AllowedCaller = "direct"`

        - `const CodeExecutionTool20250825AllowedCallerCodeExecution20250825 CodeExecutionTool20250825AllowedCaller = "code_execution_20250825"`

        - `const CodeExecutionTool20250825AllowedCallerCodeExecution20260120 CodeExecutionTool20250825AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type CodeExecutionTool20260120 struct{…}`

      Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

      - `Name CodeExecution`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

      - `AllowedCallers []string`

        - `const CodeExecutionTool20260120AllowedCallerDirect CodeExecutionTool20260120AllowedCaller = "direct"`

        - `const CodeExecutionTool20260120AllowedCallerCodeExecution20250825 CodeExecutionTool20260120AllowedCaller = "code_execution_20250825"`

        - `const CodeExecutionTool20260120AllowedCallerCodeExecution20260120 CodeExecutionTool20260120AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type MemoryTool20250818 struct{…}`

      - `Name Memory`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const MemoryMemory Memory = "memory"`

      - `Type Memory20250818`

        - `const Memory20250818Memory20250818 Memory20250818 = "memory_20250818"`

      - `AllowedCallers []string`

        - `const MemoryTool20250818AllowedCallerDirect MemoryTool20250818AllowedCaller = "direct"`

        - `const MemoryTool20250818AllowedCallerCodeExecution20250825 MemoryTool20250818AllowedCaller = "code_execution_20250825"`

        - `const MemoryTool20250818AllowedCallerCodeExecution20260120 MemoryTool20250818AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type ToolTextEditor20250124 struct{…}`

      - `Name StrReplaceEditor`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const StrReplaceEditorStrReplaceEditor StrReplaceEditor = "str_replace_editor"`

      - `Type TextEditor20250124`

        - `const TextEditor20250124TextEditor20250124 TextEditor20250124 = "text_editor_20250124"`

      - `AllowedCallers []string`

        - `const ToolTextEditor20250124AllowedCallerDirect ToolTextEditor20250124AllowedCaller = "direct"`

        - `const ToolTextEditor20250124AllowedCallerCodeExecution20250825 ToolTextEditor20250124AllowedCaller = "code_execution_20250825"`

        - `const ToolTextEditor20250124AllowedCallerCodeExecution20260120 ToolTextEditor20250124AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type ToolTextEditor20250429 struct{…}`

      - `Name StrReplaceBasedEditTool`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

      - `Type TextEditor20250429`

        - `const TextEditor20250429TextEditor20250429 TextEditor20250429 = "text_editor_20250429"`

      - `AllowedCallers []string`

        - `const ToolTextEditor20250429AllowedCallerDirect ToolTextEditor20250429AllowedCaller = "direct"`

        - `const ToolTextEditor20250429AllowedCallerCodeExecution20250825 ToolTextEditor20250429AllowedCaller = "code_execution_20250825"`

        - `const ToolTextEditor20250429AllowedCallerCodeExecution20260120 ToolTextEditor20250429AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type ToolTextEditor20250728 struct{…}`

      - `Name StrReplaceBasedEditTool`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

      - `Type TextEditor20250728`

        - `const TextEditor20250728TextEditor20250728 TextEditor20250728 = "text_editor_20250728"`

      - `AllowedCallers []string`

        - `const ToolTextEditor20250728AllowedCallerDirect ToolTextEditor20250728AllowedCaller = "direct"`

        - `const ToolTextEditor20250728AllowedCallerCodeExecution20250825 ToolTextEditor20250728AllowedCaller = "code_execution_20250825"`

        - `const ToolTextEditor20250728AllowedCallerCodeExecution20260120 ToolTextEditor20250728AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `InputExamples []map[string, any]`

      - `MaxCharacters int64`

        Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type WebSearchTool20250305 struct{…}`

      - `Name WebSearch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebSearchWebSearch WebSearch = "web_search"`

      - `Type WebSearch20250305`

        - `const WebSearch20250305WebSearch20250305 WebSearch20250305 = "web_search_20250305"`

      - `AllowedCallers []string`

        - `const WebSearchTool20250305AllowedCallerDirect WebSearchTool20250305AllowedCaller = "direct"`

        - `const WebSearchTool20250305AllowedCallerCodeExecution20250825 WebSearchTool20250305AllowedCaller = "code_execution_20250825"`

        - `const WebSearchTool20250305AllowedCallerCodeExecution20260120 WebSearchTool20250305AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

      - `BlockedDomains []string`

        If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

      - `UserLocation UserLocation`

        Parameters for the user's location. Used to provide more relevant search results.

        - `Type Approximate`

          - `const ApproximateApproximate Approximate = "approximate"`

        - `City string`

          The city of the user.

        - `Country string`

          The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user.

        - `Region string`

          The region of the user.

        - `Timezone string`

          The [IANA timezone](https://nodatime.org/TimeZones) of the user.

    - `type WebFetchTool20250910 struct{…}`

      - `Name WebFetch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebFetchWebFetch WebFetch = "web_fetch"`

      - `Type WebFetch20250910`

        - `const WebFetch20250910WebFetch20250910 WebFetch20250910 = "web_fetch_20250910"`

      - `AllowedCallers []string`

        - `const WebFetchTool20250910AllowedCallerDirect WebFetchTool20250910AllowedCaller = "direct"`

        - `const WebFetchTool20250910AllowedCallerCodeExecution20250825 WebFetchTool20250910AllowedCaller = "code_execution_20250825"`

        - `const WebFetchTool20250910AllowedCallerCodeExecution20260120 WebFetchTool20250910AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        List of domains to allow fetching from

      - `BlockedDomains []string`

        List of domains to block fetching from

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations CitationsConfigParamResp`

        Citations configuration for fetched documents. Citations are disabled by default.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxContentTokens int64`

        Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type WebSearchTool20260209 struct{…}`

      - `Name WebSearch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebSearchWebSearch WebSearch = "web_search"`

      - `Type WebSearch20260209`

        - `const WebSearch20260209WebSearch20260209 WebSearch20260209 = "web_search_20260209"`

      - `AllowedCallers []string`

        - `const WebSearchTool20260209AllowedCallerDirect WebSearchTool20260209AllowedCaller = "direct"`

        - `const WebSearchTool20260209AllowedCallerCodeExecution20250825 WebSearchTool20260209AllowedCaller = "code_execution_20250825"`

        - `const WebSearchTool20260209AllowedCallerCodeExecution20260120 WebSearchTool20260209AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

      - `BlockedDomains []string`

        If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

      - `UserLocation UserLocation`

        Parameters for the user's location. Used to provide more relevant search results.

    - `type WebFetchTool20260209 struct{…}`

      - `Name WebFetch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebFetchWebFetch WebFetch = "web_fetch"`

      - `Type WebFetch20260209`

        - `const WebFetch20260209WebFetch20260209 WebFetch20260209 = "web_fetch_20260209"`

      - `AllowedCallers []string`

        - `const WebFetchTool20260209AllowedCallerDirect WebFetchTool20260209AllowedCaller = "direct"`

        - `const WebFetchTool20260209AllowedCallerCodeExecution20250825 WebFetchTool20260209AllowedCaller = "code_execution_20250825"`

        - `const WebFetchTool20260209AllowedCallerCodeExecution20260120 WebFetchTool20260209AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        List of domains to allow fetching from

      - `BlockedDomains []string`

        List of domains to block fetching from

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations CitationsConfigParamResp`

        Citations configuration for fetched documents. Citations are disabled by default.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxContentTokens int64`

        Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type WebFetchTool20260309 struct{…}`

      Web fetch tool with use_cache parameter for bypassing cached content.

      - `Name WebFetch`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const WebFetchWebFetch WebFetch = "web_fetch"`

      - `Type WebFetch20260309`

        - `const WebFetch20260309WebFetch20260309 WebFetch20260309 = "web_fetch_20260309"`

      - `AllowedCallers []string`

        - `const WebFetchTool20260309AllowedCallerDirect WebFetchTool20260309AllowedCaller = "direct"`

        - `const WebFetchTool20260309AllowedCallerCodeExecution20250825 WebFetchTool20260309AllowedCaller = "code_execution_20250825"`

        - `const WebFetchTool20260309AllowedCallerCodeExecution20260120 WebFetchTool20260309AllowedCaller = "code_execution_20260120"`

      - `AllowedDomains []string`

        List of domains to allow fetching from

      - `BlockedDomains []string`

        List of domains to block fetching from

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations CitationsConfigParamResp`

        Citations configuration for fetched documents. Citations are disabled by default.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `MaxContentTokens int64`

        Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

      - `MaxUses int64`

        Maximum number of times the tool can be used in the API request.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

      - `UseCache bool`

        Whether to use cached content. Set to false to bypass the cache and fetch fresh content. Only set to false when the user explicitly requests fresh content or when fetching rapidly-changing sources.

    - `type ToolSearchToolBm25_20251119 struct{…}`

      - `Name ToolSearchToolBm25`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const ToolSearchToolBm25ToolSearchToolBm25 ToolSearchToolBm25 = "tool_search_tool_bm25"`

      - `Type ToolSearchToolBm25_20251119Type`

        - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25_20251119 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25_20251119"`

        - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25"`

      - `AllowedCallers []string`

        - `const ToolSearchToolBm25_20251119AllowedCallerDirect ToolSearchToolBm25_20251119AllowedCaller = "direct"`

        - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20250825 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20250825"`

        - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20260120 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

    - `type ToolSearchToolRegex20251119 struct{…}`

      - `Name ToolSearchToolRegex`

        Name of the tool.

        This is how the tool will be called by the model and in `tool_use` blocks.

        - `const ToolSearchToolRegexToolSearchToolRegex ToolSearchToolRegex = "tool_search_tool_regex"`

      - `Type ToolSearchToolRegex20251119Type`

        - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex20251119 ToolSearchToolRegex20251119Type = "tool_search_tool_regex_20251119"`

        - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex ToolSearchToolRegex20251119Type = "tool_search_tool_regex"`

      - `AllowedCallers []string`

        - `const ToolSearchToolRegex20251119AllowedCallerDirect ToolSearchToolRegex20251119AllowedCaller = "direct"`

        - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20250825 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20250825"`

        - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20260120 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20260120"`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `DeferLoading bool`

        If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

      - `Strict bool`

        When true, guarantees schema validation on tool names and inputs

### Returns

- `type MessageTokensCount struct{…}`

  - `InputTokens int64`

    The total number of tokens across the provided list of messages, system prompt, and tools.

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/anthropics/anthropic-sdk-go"
  "github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
  client := anthropic.NewClient(
    option.WithAPIKey("my-anthropic-api-key"),
  )
  messageTokensCount, err := client.Messages.CountTokens(context.TODO(), anthropic.MessageCountTokensParams{
    Messages: []anthropic.MessageParam{anthropic.MessageParam{
      Content: []anthropic.ContentBlockParamUnion{anthropic.ContentBlockParamUnion{
        OfText: &anthropic.TextBlockParam{
          Text: "x",
        },
      }},
      Role: anthropic.MessageParamRoleUser,
    }},
    Model: anthropic.ModelClaudeOpus4_6,
  })
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", messageTokensCount.InputTokens)
}
```

#### Response

```json
{
  "input_tokens": 2095
}
```

## Domain Types

### Base64 Image Source

- `type Base64ImageSource struct{…}`

  - `Data string`

  - `MediaType Base64ImageSourceMediaType`

    - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

    - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

    - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

    - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

  - `Type Base64`

    - `const Base64Base64 Base64 = "base64"`

### Base64 PDF Source

- `type Base64PDFSource struct{…}`

  - `Data string`

  - `MediaType ApplicationPDF`

    - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

  - `Type Base64`

    - `const Base64Base64 Base64 = "base64"`

### Bash Code Execution Output Block

- `type BashCodeExecutionOutputBlock struct{…}`

  - `FileID string`

  - `Type BashCodeExecutionOutput`

    - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

### Bash Code Execution Output Block Param

- `type BashCodeExecutionOutputBlockParamResp struct{…}`

  - `FileID string`

  - `Type BashCodeExecutionOutput`

    - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

### Bash Code Execution Result Block

- `type BashCodeExecutionResultBlock struct{…}`

  - `Content []BashCodeExecutionOutputBlock`

    - `FileID string`

    - `Type BashCodeExecutionOutput`

      - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

  - `ReturnCode int64`

  - `Stderr string`

  - `Stdout string`

  - `Type BashCodeExecutionResult`

    - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

### Bash Code Execution Result Block Param

- `type BashCodeExecutionResultBlockParamResp struct{…}`

  - `Content []BashCodeExecutionOutputBlockParamResp`

    - `FileID string`

    - `Type BashCodeExecutionOutput`

      - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

  - `ReturnCode int64`

  - `Stderr string`

  - `Stdout string`

  - `Type BashCodeExecutionResult`

    - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

### Bash Code Execution Tool Result Block

- `type BashCodeExecutionToolResultBlock struct{…}`

  - `Content BashCodeExecutionToolResultBlockContentUnion`

    - `type BashCodeExecutionToolResultError struct{…}`

      - `ErrorCode BashCodeExecutionToolResultErrorCode`

        - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

        - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

        - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

        - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

        - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

      - `Type BashCodeExecutionToolResultError`

        - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

    - `type BashCodeExecutionResultBlock struct{…}`

      - `Content []BashCodeExecutionOutputBlock`

        - `FileID string`

        - `Type BashCodeExecutionOutput`

          - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

      - `ReturnCode int64`

      - `Stderr string`

      - `Stdout string`

      - `Type BashCodeExecutionResult`

        - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

  - `ToolUseID string`

  - `Type BashCodeExecutionToolResult`

    - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

### Bash Code Execution Tool Result Block Param

- `type BashCodeExecutionToolResultBlockParamResp struct{…}`

  - `Content BashCodeExecutionToolResultBlockParamContentUnionResp`

    - `type BashCodeExecutionToolResultErrorParamResp struct{…}`

      - `ErrorCode BashCodeExecutionToolResultErrorCode`

        - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

        - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

        - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

        - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

        - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

      - `Type BashCodeExecutionToolResultError`

        - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

    - `type BashCodeExecutionResultBlockParamResp struct{…}`

      - `Content []BashCodeExecutionOutputBlockParamResp`

        - `FileID string`

        - `Type BashCodeExecutionOutput`

          - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

      - `ReturnCode int64`

      - `Stderr string`

      - `Stdout string`

      - `Type BashCodeExecutionResult`

        - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

  - `ToolUseID string`

  - `Type BashCodeExecutionToolResult`

    - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

### Bash Code Execution Tool Result Error

- `type BashCodeExecutionToolResultError struct{…}`

  - `ErrorCode BashCodeExecutionToolResultErrorCode`

    - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

    - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

    - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

    - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

    - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

  - `Type BashCodeExecutionToolResultError`

    - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

### Bash Code Execution Tool Result Error Code

- `type BashCodeExecutionToolResultErrorCode string`

  - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

  - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

  - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

  - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

  - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

### Bash Code Execution Tool Result Error Param

- `type BashCodeExecutionToolResultErrorParamResp struct{…}`

  - `ErrorCode BashCodeExecutionToolResultErrorCode`

    - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

    - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

    - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

    - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

    - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

  - `Type BashCodeExecutionToolResultError`

    - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

### Cache Control Ephemeral

- `type CacheControlEphemeral struct{…}`

  - `Type Ephemeral`

    - `const EphemeralEphemeral Ephemeral = "ephemeral"`

  - `TTL CacheControlEphemeralTTL`

    The time-to-live for the cache control breakpoint.

    This may be one the following values:

    - `5m`: 5 minutes
    - `1h`: 1 hour

    Defaults to `5m`.

    - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

    - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

### Cache Creation

- `type CacheCreation struct{…}`

  - `Ephemeral1hInputTokens int64`

    The number of input tokens used to create the 1 hour cache entry.

  - `Ephemeral5mInputTokens int64`

    The number of input tokens used to create the 5 minute cache entry.

### Citation Char Location

- `type CitationCharLocation struct{…}`

  - `CitedText string`

  - `DocumentIndex int64`

  - `DocumentTitle string`

  - `EndCharIndex int64`

  - `FileID string`

  - `StartCharIndex int64`

  - `Type CharLocation`

    - `const CharLocationCharLocation CharLocation = "char_location"`

### Citation Char Location Param

- `type CitationCharLocationParamResp struct{…}`

  - `CitedText string`

  - `DocumentIndex int64`

  - `DocumentTitle string`

  - `EndCharIndex int64`

  - `StartCharIndex int64`

  - `Type CharLocation`

    - `const CharLocationCharLocation CharLocation = "char_location"`

### Citation Content Block Location

- `type CitationContentBlockLocation struct{…}`

  - `CitedText string`

    The full text of the cited block range, concatenated.

    Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

  - `DocumentIndex int64`

  - `DocumentTitle string`

  - `EndBlockIndex int64`

    Exclusive 0-based end index of the cited block range in the source's `content` array.

    Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

  - `FileID string`

  - `StartBlockIndex int64`

    0-based index of the first cited block in the source's `content` array.

  - `Type ContentBlockLocation`

    - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

### Citation Content Block Location Param

- `type CitationContentBlockLocationParamResp struct{…}`

  - `CitedText string`

    The full text of the cited block range, concatenated.

    Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

  - `DocumentIndex int64`

  - `DocumentTitle string`

  - `EndBlockIndex int64`

    Exclusive 0-based end index of the cited block range in the source's `content` array.

    Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

  - `StartBlockIndex int64`

    0-based index of the first cited block in the source's `content` array.

  - `Type ContentBlockLocation`

    - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

### Citation Page Location

- `type CitationPageLocation struct{…}`

  - `CitedText string`

  - `DocumentIndex int64`

  - `DocumentTitle string`

  - `EndPageNumber int64`

  - `FileID string`

  - `StartPageNumber int64`

  - `Type PageLocation`

    - `const PageLocationPageLocation PageLocation = "page_location"`

### Citation Page Location Param

- `type CitationPageLocationParamResp struct{…}`

  - `CitedText string`

  - `DocumentIndex int64`

  - `DocumentTitle string`

  - `EndPageNumber int64`

  - `StartPageNumber int64`

  - `Type PageLocation`

    - `const PageLocationPageLocation PageLocation = "page_location"`

### Citation Search Result Location Param

- `type CitationSearchResultLocationParamResp struct{…}`

  - `CitedText string`

    The full text of the cited block range, concatenated.

    Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

  - `EndBlockIndex int64`

    Exclusive 0-based end index of the cited block range in the source's `content` array.

    Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

  - `SearchResultIndex int64`

    0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

    Counted separately from `document_index`; server-side web search results are not included in this count.

  - `Source string`

  - `StartBlockIndex int64`

    0-based index of the first cited block in the source's `content` array.

  - `Title string`

  - `Type SearchResultLocation`

    - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

### Citation Web Search Result Location Param

- `type CitationWebSearchResultLocationParamResp struct{…}`

  - `CitedText string`

  - `EncryptedIndex string`

  - `Title string`

  - `Type WebSearchResultLocation`

    - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

  - `URL string`

### Citations Config

- `type CitationsConfig struct{…}`

  - `Enabled bool`

### Citations Config Param

- `type CitationsConfigParamResp struct{…}`

  - `Enabled bool`

### Citations Delta

- `type CitationsDelta struct{…}`

  - `Citation CitationsDeltaCitationUnion`

    - `type CitationCharLocation struct{…}`

      - `CitedText string`

      - `DocumentIndex int64`

      - `DocumentTitle string`

      - `EndCharIndex int64`

      - `FileID string`

      - `StartCharIndex int64`

      - `Type CharLocation`

        - `const CharLocationCharLocation CharLocation = "char_location"`

    - `type CitationPageLocation struct{…}`

      - `CitedText string`

      - `DocumentIndex int64`

      - `DocumentTitle string`

      - `EndPageNumber int64`

      - `FileID string`

      - `StartPageNumber int64`

      - `Type PageLocation`

        - `const PageLocationPageLocation PageLocation = "page_location"`

    - `type CitationContentBlockLocation struct{…}`

      - `CitedText string`

        The full text of the cited block range, concatenated.

        Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

      - `DocumentIndex int64`

      - `DocumentTitle string`

      - `EndBlockIndex int64`

        Exclusive 0-based end index of the cited block range in the source's `content` array.

        Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

      - `FileID string`

      - `StartBlockIndex int64`

        0-based index of the first cited block in the source's `content` array.

      - `Type ContentBlockLocation`

        - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

    - `type CitationsWebSearchResultLocation struct{…}`

      - `CitedText string`

      - `EncryptedIndex string`

      - `Title string`

      - `Type WebSearchResultLocation`

        - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

      - `URL string`

    - `type CitationsSearchResultLocation struct{…}`

      - `CitedText string`

        The full text of the cited block range, concatenated.

        Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

      - `EndBlockIndex int64`

        Exclusive 0-based end index of the cited block range in the source's `content` array.

        Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

      - `SearchResultIndex int64`

        0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

        Counted separately from `document_index`; server-side web search results are not included in this count.

      - `Source string`

      - `StartBlockIndex int64`

        0-based index of the first cited block in the source's `content` array.

      - `Title string`

      - `Type SearchResultLocation`

        - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

  - `Type CitationsDelta`

    - `const CitationsDeltaCitationsDelta CitationsDelta = "citations_delta"`

### Citations Search Result Location

- `type CitationsSearchResultLocation struct{…}`

  - `CitedText string`

    The full text of the cited block range, concatenated.

    Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

  - `EndBlockIndex int64`

    Exclusive 0-based end index of the cited block range in the source's `content` array.

    Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

  - `SearchResultIndex int64`

    0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

    Counted separately from `document_index`; server-side web search results are not included in this count.

  - `Source string`

  - `StartBlockIndex int64`

    0-based index of the first cited block in the source's `content` array.

  - `Title string`

  - `Type SearchResultLocation`

    - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

### Citations Web Search Result Location

- `type CitationsWebSearchResultLocation struct{…}`

  - `CitedText string`

  - `EncryptedIndex string`

  - `Title string`

  - `Type WebSearchResultLocation`

    - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

  - `URL string`

### Code Execution Output Block

- `type CodeExecutionOutputBlock struct{…}`

  - `FileID string`

  - `Type CodeExecutionOutput`

    - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

### Code Execution Output Block Param

- `type CodeExecutionOutputBlockParamResp struct{…}`

  - `FileID string`

  - `Type CodeExecutionOutput`

    - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

### Code Execution Result Block

- `type CodeExecutionResultBlock struct{…}`

  - `Content []CodeExecutionOutputBlock`

    - `FileID string`

    - `Type CodeExecutionOutput`

      - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

  - `ReturnCode int64`

  - `Stderr string`

  - `Stdout string`

  - `Type CodeExecutionResult`

    - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

### Code Execution Result Block Param

- `type CodeExecutionResultBlockParamResp struct{…}`

  - `Content []CodeExecutionOutputBlockParamResp`

    - `FileID string`

    - `Type CodeExecutionOutput`

      - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

  - `ReturnCode int64`

  - `Stderr string`

  - `Stdout string`

  - `Type CodeExecutionResult`

    - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

### Code Execution Tool 20250522

- `type CodeExecutionTool20250522 struct{…}`

  - `Name CodeExecution`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

  - `Type CodeExecution20250522`

    - `const CodeExecution20250522CodeExecution20250522 CodeExecution20250522 = "code_execution_20250522"`

  - `AllowedCallers []string`

    - `const CodeExecutionTool20250522AllowedCallerDirect CodeExecutionTool20250522AllowedCaller = "direct"`

    - `const CodeExecutionTool20250522AllowedCallerCodeExecution20250825 CodeExecutionTool20250522AllowedCaller = "code_execution_20250825"`

    - `const CodeExecutionTool20250522AllowedCallerCodeExecution20260120 CodeExecutionTool20250522AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Code Execution Tool 20250825

- `type CodeExecutionTool20250825 struct{…}`

  - `Name CodeExecution`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

  - `Type CodeExecution20250825`

    - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

  - `AllowedCallers []string`

    - `const CodeExecutionTool20250825AllowedCallerDirect CodeExecutionTool20250825AllowedCaller = "direct"`

    - `const CodeExecutionTool20250825AllowedCallerCodeExecution20250825 CodeExecutionTool20250825AllowedCaller = "code_execution_20250825"`

    - `const CodeExecutionTool20250825AllowedCallerCodeExecution20260120 CodeExecutionTool20250825AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Code Execution Tool 20260120

- `type CodeExecutionTool20260120 struct{…}`

  Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

  - `Name CodeExecution`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

  - `Type CodeExecution20260120`

    - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

  - `AllowedCallers []string`

    - `const CodeExecutionTool20260120AllowedCallerDirect CodeExecutionTool20260120AllowedCaller = "direct"`

    - `const CodeExecutionTool20260120AllowedCallerCodeExecution20250825 CodeExecutionTool20260120AllowedCaller = "code_execution_20250825"`

    - `const CodeExecutionTool20260120AllowedCallerCodeExecution20260120 CodeExecutionTool20260120AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Code Execution Tool Result Block

- `type CodeExecutionToolResultBlock struct{…}`

  - `Content CodeExecutionToolResultBlockContentUnion`

    Code execution result with encrypted stdout for PFC + web_search results.

    - `type CodeExecutionToolResultError struct{…}`

      - `ErrorCode CodeExecutionToolResultErrorCode`

        - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

        - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

        - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

        - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

      - `Type CodeExecutionToolResultError`

        - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

    - `type CodeExecutionResultBlock struct{…}`

      - `Content []CodeExecutionOutputBlock`

        - `FileID string`

        - `Type CodeExecutionOutput`

          - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

      - `ReturnCode int64`

      - `Stderr string`

      - `Stdout string`

      - `Type CodeExecutionResult`

        - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

    - `type EncryptedCodeExecutionResultBlock struct{…}`

      Code execution result with encrypted stdout for PFC + web_search results.

      - `Content []CodeExecutionOutputBlock`

        - `FileID string`

        - `Type CodeExecutionOutput`

      - `EncryptedStdout string`

      - `ReturnCode int64`

      - `Stderr string`

      - `Type EncryptedCodeExecutionResult`

        - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

  - `ToolUseID string`

  - `Type CodeExecutionToolResult`

    - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

### Code Execution Tool Result Block Content

- `type CodeExecutionToolResultBlockContentUnion interface{…}`

  Code execution result with encrypted stdout for PFC + web_search results.

  - `type CodeExecutionToolResultError struct{…}`

    - `ErrorCode CodeExecutionToolResultErrorCode`

      - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

      - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

      - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

      - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

    - `Type CodeExecutionToolResultError`

      - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

  - `type CodeExecutionResultBlock struct{…}`

    - `Content []CodeExecutionOutputBlock`

      - `FileID string`

      - `Type CodeExecutionOutput`

        - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

    - `ReturnCode int64`

    - `Stderr string`

    - `Stdout string`

    - `Type CodeExecutionResult`

      - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

  - `type EncryptedCodeExecutionResultBlock struct{…}`

    Code execution result with encrypted stdout for PFC + web_search results.

    - `Content []CodeExecutionOutputBlock`

      - `FileID string`

      - `Type CodeExecutionOutput`

    - `EncryptedStdout string`

    - `ReturnCode int64`

    - `Stderr string`

    - `Type EncryptedCodeExecutionResult`

      - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

### Code Execution Tool Result Block Param

- `type CodeExecutionToolResultBlockParamResp struct{…}`

  - `Content CodeExecutionToolResultBlockParamContentUnionResp`

    Code execution result with encrypted stdout for PFC + web_search results.

    - `type CodeExecutionToolResultErrorParamResp struct{…}`

      - `ErrorCode CodeExecutionToolResultErrorCode`

        - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

        - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

        - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

        - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

      - `Type CodeExecutionToolResultError`

        - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

    - `type CodeExecutionResultBlockParamResp struct{…}`

      - `Content []CodeExecutionOutputBlockParamResp`

        - `FileID string`

        - `Type CodeExecutionOutput`

          - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

      - `ReturnCode int64`

      - `Stderr string`

      - `Stdout string`

      - `Type CodeExecutionResult`

        - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

    - `type EncryptedCodeExecutionResultBlockParamResp struct{…}`

      Code execution result with encrypted stdout for PFC + web_search results.

      - `Content []CodeExecutionOutputBlockParamResp`

        - `FileID string`

        - `Type CodeExecutionOutput`

      - `EncryptedStdout string`

      - `ReturnCode int64`

      - `Stderr string`

      - `Type EncryptedCodeExecutionResult`

        - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

  - `ToolUseID string`

  - `Type CodeExecutionToolResult`

    - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

### Code Execution Tool Result Block Param Content

- `type CodeExecutionToolResultBlockParamContentUnionResp interface{…}`

  Code execution result with encrypted stdout for PFC + web_search results.

  - `type CodeExecutionToolResultErrorParamResp struct{…}`

    - `ErrorCode CodeExecutionToolResultErrorCode`

      - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

      - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

      - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

      - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

    - `Type CodeExecutionToolResultError`

      - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

  - `type CodeExecutionResultBlockParamResp struct{…}`

    - `Content []CodeExecutionOutputBlockParamResp`

      - `FileID string`

      - `Type CodeExecutionOutput`

        - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

    - `ReturnCode int64`

    - `Stderr string`

    - `Stdout string`

    - `Type CodeExecutionResult`

      - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

  - `type EncryptedCodeExecutionResultBlockParamResp struct{…}`

    Code execution result with encrypted stdout for PFC + web_search results.

    - `Content []CodeExecutionOutputBlockParamResp`

      - `FileID string`

      - `Type CodeExecutionOutput`

    - `EncryptedStdout string`

    - `ReturnCode int64`

    - `Stderr string`

    - `Type EncryptedCodeExecutionResult`

      - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

### Code Execution Tool Result Error

- `type CodeExecutionToolResultError struct{…}`

  - `ErrorCode CodeExecutionToolResultErrorCode`

    - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

    - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

    - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

    - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

  - `Type CodeExecutionToolResultError`

    - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

### Code Execution Tool Result Error Code

- `type CodeExecutionToolResultErrorCode string`

  - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

  - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

  - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

  - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

### Code Execution Tool Result Error Param

- `type CodeExecutionToolResultErrorParamResp struct{…}`

  - `ErrorCode CodeExecutionToolResultErrorCode`

    - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

    - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

    - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

    - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

  - `Type CodeExecutionToolResultError`

    - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

### Container

- `type Container struct{…}`

  Information about the container used in the request (for the code execution tool)

  - `ID string`

    Identifier for the container used in this request

  - `ExpiresAt Time`

    The time at which the container will expire.

### Container Upload Block

- `type ContainerUploadBlock struct{…}`

  Response model for a file uploaded to the container.

  - `FileID string`

  - `Type ContainerUpload`

    - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

### Container Upload Block Param

- `type ContainerUploadBlockParamResp struct{…}`

  A content block that represents a file to be uploaded to the container
  Files uploaded via this block will be available in the container's input directory.

  - `FileID string`

  - `Type ContainerUpload`

    - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

### Content Block

- `type ContentBlockUnion interface{…}`

  Response model for a file uploaded to the container.

  - `type TextBlock struct{…}`

    - `Citations []TextCitationUnion`

      Citations supporting the text block.

      The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

      - `type CitationCharLocation struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndCharIndex int64`

        - `FileID string`

        - `StartCharIndex int64`

        - `Type CharLocation`

          - `const CharLocationCharLocation CharLocation = "char_location"`

      - `type CitationPageLocation struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndPageNumber int64`

        - `FileID string`

        - `StartPageNumber int64`

        - `Type PageLocation`

          - `const PageLocationPageLocation PageLocation = "page_location"`

      - `type CitationContentBlockLocation struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `FileID string`

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Type ContentBlockLocation`

          - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

      - `type CitationsWebSearchResultLocation struct{…}`

        - `CitedText string`

        - `EncryptedIndex string`

        - `Title string`

        - `Type WebSearchResultLocation`

          - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

        - `URL string`

      - `type CitationsSearchResultLocation struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `SearchResultIndex int64`

          0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

          Counted separately from `document_index`; server-side web search results are not included in this count.

        - `Source string`

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Title string`

        - `Type SearchResultLocation`

          - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

    - `Text string`

    - `Type Text`

      - `const TextText Text = "text"`

  - `type ThinkingBlock struct{…}`

    - `Signature string`

    - `Thinking string`

    - `Type Thinking`

      - `const ThinkingThinking Thinking = "thinking"`

  - `type RedactedThinkingBlock struct{…}`

    - `Data string`

    - `Type RedactedThinking`

      - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

  - `type ToolUseBlock struct{…}`

    - `ID string`

    - `Caller ToolUseBlockCallerUnion`

      Tool invocation directly from the model.

      - `type DirectCaller struct{…}`

        Tool invocation directly from the model.

        - `Type Direct`

          - `const DirectDirect Direct = "direct"`

      - `type ServerToolCaller struct{…}`

        Tool invocation generated by a server-side tool.

        - `ToolID string`

        - `Type CodeExecution20250825`

          - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

      - `type ServerToolCaller20260120 struct{…}`

        - `ToolID string`

        - `Type CodeExecution20260120`

          - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

    - `Input map[string, any]`

    - `Name string`

    - `Type ToolUse`

      - `const ToolUseToolUse ToolUse = "tool_use"`

  - `type ServerToolUseBlock struct{…}`

    - `ID string`

    - `Caller ServerToolUseBlockCallerUnion`

      Tool invocation directly from the model.

      - `type DirectCaller struct{…}`

        Tool invocation directly from the model.

      - `type ServerToolCaller struct{…}`

        Tool invocation generated by a server-side tool.

      - `type ServerToolCaller20260120 struct{…}`

    - `Input map[string, any]`

    - `Name ServerToolUseBlockName`

      - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

      - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

      - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

      - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

      - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

      - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

      - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

    - `Type ServerToolUse`

      - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

  - `type WebSearchToolResultBlock struct{…}`

    - `Caller WebSearchToolResultBlockCallerUnion`

      Tool invocation directly from the model.

      - `type DirectCaller struct{…}`

        Tool invocation directly from the model.

      - `type ServerToolCaller struct{…}`

        Tool invocation generated by a server-side tool.

      - `type ServerToolCaller20260120 struct{…}`

    - `Content WebSearchToolResultBlockContentUnion`

      - `type WebSearchToolResultError struct{…}`

        - `ErrorCode WebSearchToolResultErrorCode`

          - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

          - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

          - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

          - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

          - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

          - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

        - `Type WebSearchToolResultError`

          - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

      - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

        - `EncryptedContent string`

        - `PageAge string`

        - `Title string`

        - `Type WebSearchResult`

          - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

        - `URL string`

    - `ToolUseID string`

    - `Type WebSearchToolResult`

      - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

  - `type WebFetchToolResultBlock struct{…}`

    - `Caller WebFetchToolResultBlockCallerUnion`

      Tool invocation directly from the model.

      - `type DirectCaller struct{…}`

        Tool invocation directly from the model.

      - `type ServerToolCaller struct{…}`

        Tool invocation generated by a server-side tool.

      - `type ServerToolCaller20260120 struct{…}`

    - `Content WebFetchToolResultBlockContentUnion`

      - `type WebFetchToolResultErrorBlock struct{…}`

        - `ErrorCode WebFetchToolResultErrorCode`

          - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

          - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

          - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

          - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

          - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

          - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

          - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

          - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

          - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

        - `Type WebFetchToolResultError`

          - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

      - `type WebFetchBlock struct{…}`

        - `Content DocumentBlock`

          - `Citations CitationsConfig`

            Citation configuration for the document

            - `Enabled bool`

          - `Source DocumentBlockSourceUnion`

            - `type Base64PDFSource struct{…}`

              - `Data string`

              - `MediaType ApplicationPDF`

                - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

              - `Type Base64`

                - `const Base64Base64 Base64 = "base64"`

            - `type PlainTextSource struct{…}`

              - `Data string`

              - `MediaType TextPlain`

                - `const TextPlainTextPlain TextPlain = "text/plain"`

              - `Type Text`

                - `const TextText Text = "text"`

          - `Title string`

            The title of the document

          - `Type Document`

            - `const DocumentDocument Document = "document"`

        - `RetrievedAt string`

          ISO 8601 timestamp when the content was retrieved

        - `Type WebFetchResult`

          - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

        - `URL string`

          Fetched content URL

    - `ToolUseID string`

    - `Type WebFetchToolResult`

      - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

  - `type CodeExecutionToolResultBlock struct{…}`

    - `Content CodeExecutionToolResultBlockContentUnion`

      Code execution result with encrypted stdout for PFC + web_search results.

      - `type CodeExecutionToolResultError struct{…}`

        - `ErrorCode CodeExecutionToolResultErrorCode`

          - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

          - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

          - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

          - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

        - `Type CodeExecutionToolResultError`

          - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

      - `type CodeExecutionResultBlock struct{…}`

        - `Content []CodeExecutionOutputBlock`

          - `FileID string`

          - `Type CodeExecutionOutput`

            - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

        - `ReturnCode int64`

        - `Stderr string`

        - `Stdout string`

        - `Type CodeExecutionResult`

          - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

      - `type EncryptedCodeExecutionResultBlock struct{…}`

        Code execution result with encrypted stdout for PFC + web_search results.

        - `Content []CodeExecutionOutputBlock`

          - `FileID string`

          - `Type CodeExecutionOutput`

        - `EncryptedStdout string`

        - `ReturnCode int64`

        - `Stderr string`

        - `Type EncryptedCodeExecutionResult`

          - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

    - `ToolUseID string`

    - `Type CodeExecutionToolResult`

      - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

  - `type BashCodeExecutionToolResultBlock struct{…}`

    - `Content BashCodeExecutionToolResultBlockContentUnion`

      - `type BashCodeExecutionToolResultError struct{…}`

        - `ErrorCode BashCodeExecutionToolResultErrorCode`

          - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

          - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

          - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

          - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

          - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

        - `Type BashCodeExecutionToolResultError`

          - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

      - `type BashCodeExecutionResultBlock struct{…}`

        - `Content []BashCodeExecutionOutputBlock`

          - `FileID string`

          - `Type BashCodeExecutionOutput`

            - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

        - `ReturnCode int64`

        - `Stderr string`

        - `Stdout string`

        - `Type BashCodeExecutionResult`

          - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

    - `ToolUseID string`

    - `Type BashCodeExecutionToolResult`

      - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

  - `type TextEditorCodeExecutionToolResultBlock struct{…}`

    - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

      - `type TextEditorCodeExecutionToolResultError struct{…}`

        - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

          - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

          - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

          - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

          - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

          - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

        - `ErrorMessage string`

        - `Type TextEditorCodeExecutionToolResultError`

          - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

      - `type TextEditorCodeExecutionViewResultBlock struct{…}`

        - `Content string`

        - `FileType TextEditorCodeExecutionViewResultBlockFileType`

          - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

          - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

          - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

        - `NumLines int64`

        - `StartLine int64`

        - `TotalLines int64`

        - `Type TextEditorCodeExecutionViewResult`

          - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

      - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

        - `IsFileUpdate bool`

        - `Type TextEditorCodeExecutionCreateResult`

          - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

      - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

        - `Lines []string`

        - `NewLines int64`

        - `NewStart int64`

        - `OldLines int64`

        - `OldStart int64`

        - `Type TextEditorCodeExecutionStrReplaceResult`

          - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

    - `ToolUseID string`

    - `Type TextEditorCodeExecutionToolResult`

      - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

  - `type ToolSearchToolResultBlock struct{…}`

    - `Content ToolSearchToolResultBlockContentUnion`

      - `type ToolSearchToolResultError struct{…}`

        - `ErrorCode ToolSearchToolResultErrorCode`

          - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

          - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

          - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

          - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

        - `ErrorMessage string`

        - `Type ToolSearchToolResultError`

          - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

      - `type ToolSearchToolSearchResultBlock struct{…}`

        - `ToolReferences []ToolReferenceBlock`

          - `ToolName string`

          - `Type ToolReference`

            - `const ToolReferenceToolReference ToolReference = "tool_reference"`

        - `Type ToolSearchToolSearchResult`

          - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

    - `ToolUseID string`

    - `Type ToolSearchToolResult`

      - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

  - `type ContainerUploadBlock struct{…}`

    Response model for a file uploaded to the container.

    - `FileID string`

    - `Type ContainerUpload`

      - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

### Content Block Param

- `type ContentBlockParamUnionResp interface{…}`

  Regular text content.

  - `type TextBlockParamResp struct{…}`

    - `Text string`

    - `Type Text`

      - `const TextText Text = "text"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

      - `Type Ephemeral`

        - `const EphemeralEphemeral Ephemeral = "ephemeral"`

      - `TTL CacheControlEphemeralTTL`

        The time-to-live for the cache control breakpoint.

        This may be one the following values:

        - `5m`: 5 minutes
        - `1h`: 1 hour

        Defaults to `5m`.

        - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

        - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

    - `Citations []TextCitationParamUnionResp`

      - `type CitationCharLocationParamResp struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndCharIndex int64`

        - `StartCharIndex int64`

        - `Type CharLocation`

          - `const CharLocationCharLocation CharLocation = "char_location"`

      - `type CitationPageLocationParamResp struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndPageNumber int64`

        - `StartPageNumber int64`

        - `Type PageLocation`

          - `const PageLocationPageLocation PageLocation = "page_location"`

      - `type CitationContentBlockLocationParamResp struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Type ContentBlockLocation`

          - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

      - `type CitationWebSearchResultLocationParamResp struct{…}`

        - `CitedText string`

        - `EncryptedIndex string`

        - `Title string`

        - `Type WebSearchResultLocation`

          - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

        - `URL string`

      - `type CitationSearchResultLocationParamResp struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `SearchResultIndex int64`

          0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

          Counted separately from `document_index`; server-side web search results are not included in this count.

        - `Source string`

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Title string`

        - `Type SearchResultLocation`

          - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

  - `type ImageBlockParamResp struct{…}`

    - `Source ImageBlockParamSourceUnionResp`

      - `type Base64ImageSource struct{…}`

        - `Data string`

        - `MediaType Base64ImageSourceMediaType`

          - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

          - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

          - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

          - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

        - `Type Base64`

          - `const Base64Base64 Base64 = "base64"`

      - `type URLImageSource struct{…}`

        - `Type URL`

          - `const URLURL URL = "url"`

        - `URL string`

    - `Type Image`

      - `const ImageImage Image = "image"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

  - `type DocumentBlockParamResp struct{…}`

    - `Source DocumentBlockParamSourceUnionResp`

      - `type Base64PDFSource struct{…}`

        - `Data string`

        - `MediaType ApplicationPDF`

          - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

        - `Type Base64`

          - `const Base64Base64 Base64 = "base64"`

      - `type PlainTextSource struct{…}`

        - `Data string`

        - `MediaType TextPlain`

          - `const TextPlainTextPlain TextPlain = "text/plain"`

        - `Type Text`

          - `const TextText Text = "text"`

      - `type ContentBlockSource struct{…}`

        - `Content ContentBlockSourceContentUnion`

          - `string`

          - `[]ContentBlockSourceContentItemUnion`

            - `type TextBlockParamResp struct{…}`

            - `type ImageBlockParamResp struct{…}`

        - `Type Content`

          - `const ContentContent Content = "content"`

      - `type URLPDFSource struct{…}`

        - `Type URL`

          - `const URLURL URL = "url"`

        - `URL string`

    - `Type Document`

      - `const DocumentDocument Document = "document"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Citations CitationsConfigParamResp`

      - `Enabled bool`

    - `Context string`

    - `Title string`

  - `type SearchResultBlockParamResp struct{…}`

    - `Content []TextBlockParamResp`

      - `Text string`

      - `Type Text`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations []TextCitationParamUnionResp`

    - `Source string`

    - `Title string`

    - `Type SearchResult`

      - `const SearchResultSearchResult SearchResult = "search_result"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Citations CitationsConfigParamResp`

  - `type ThinkingBlockParamResp struct{…}`

    - `Signature string`

    - `Thinking string`

    - `Type Thinking`

      - `const ThinkingThinking Thinking = "thinking"`

  - `type RedactedThinkingBlockParamResp struct{…}`

    - `Data string`

    - `Type RedactedThinking`

      - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

  - `type ToolUseBlockParamResp struct{…}`

    - `ID string`

    - `Input map[string, any]`

    - `Name string`

    - `Type ToolUse`

      - `const ToolUseToolUse ToolUse = "tool_use"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Caller ToolUseBlockParamCallerUnionResp`

      Tool invocation directly from the model.

      - `type DirectCaller struct{…}`

        Tool invocation directly from the model.

        - `Type Direct`

          - `const DirectDirect Direct = "direct"`

      - `type ServerToolCaller struct{…}`

        Tool invocation generated by a server-side tool.

        - `ToolID string`

        - `Type CodeExecution20250825`

          - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

      - `type ServerToolCaller20260120 struct{…}`

        - `ToolID string`

        - `Type CodeExecution20260120`

          - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

  - `type ToolResultBlockParamResp struct{…}`

    - `ToolUseID string`

    - `Type ToolResult`

      - `const ToolResultToolResult ToolResult = "tool_result"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Content []ToolResultBlockParamContentUnionResp`

      - `[]ToolResultBlockParamContentUnionResp`

        - `type TextBlockParamResp struct{…}`

        - `type ImageBlockParamResp struct{…}`

        - `type SearchResultBlockParamResp struct{…}`

        - `type DocumentBlockParamResp struct{…}`

        - `type ToolReferenceBlockParamResp struct{…}`

          Tool reference block that can be included in tool_result content.

          - `ToolName string`

          - `Type ToolReference`

            - `const ToolReferenceToolReference ToolReference = "tool_reference"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

    - `IsError bool`

  - `type ServerToolUseBlockParamResp struct{…}`

    - `ID string`

    - `Input map[string, any]`

    - `Name ServerToolUseBlockParamName`

      - `const ServerToolUseBlockParamNameWebSearch ServerToolUseBlockParamName = "web_search"`

      - `const ServerToolUseBlockParamNameWebFetch ServerToolUseBlockParamName = "web_fetch"`

      - `const ServerToolUseBlockParamNameCodeExecution ServerToolUseBlockParamName = "code_execution"`

      - `const ServerToolUseBlockParamNameBashCodeExecution ServerToolUseBlockParamName = "bash_code_execution"`

      - `const ServerToolUseBlockParamNameTextEditorCodeExecution ServerToolUseBlockParamName = "text_editor_code_execution"`

      - `const ServerToolUseBlockParamNameToolSearchToolRegex ServerToolUseBlockParamName = "tool_search_tool_regex"`

      - `const ServerToolUseBlockParamNameToolSearchToolBm25 ServerToolUseBlockParamName = "tool_search_tool_bm25"`

    - `Type ServerToolUse`

      - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Caller ServerToolUseBlockParamCallerUnionResp`

      Tool invocation directly from the model.

      - `type DirectCaller struct{…}`

        Tool invocation directly from the model.

      - `type ServerToolCaller struct{…}`

        Tool invocation generated by a server-side tool.

      - `type ServerToolCaller20260120 struct{…}`

  - `type WebSearchToolResultBlockParamResp struct{…}`

    - `Content WebSearchToolResultBlockParamContentUnionResp`

      - `[]WebSearchResultBlockParamResp`

        - `EncryptedContent string`

        - `Title string`

        - `Type WebSearchResult`

          - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

        - `URL string`

        - `PageAge string`

      - `type WebSearchToolRequestError struct{…}`

        - `ErrorCode WebSearchToolResultErrorCode`

          - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

          - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

          - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

          - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

          - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

          - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

        - `Type WebSearchToolResultError`

          - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

    - `ToolUseID string`

    - `Type WebSearchToolResult`

      - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Caller WebSearchToolResultBlockParamCallerUnionResp`

      Tool invocation directly from the model.

      - `type DirectCaller struct{…}`

        Tool invocation directly from the model.

      - `type ServerToolCaller struct{…}`

        Tool invocation generated by a server-side tool.

      - `type ServerToolCaller20260120 struct{…}`

  - `type WebFetchToolResultBlockParamResp struct{…}`

    - `Content WebFetchToolResultBlockParamContentUnionResp`

      - `type WebFetchToolResultErrorBlockParamResp struct{…}`

        - `ErrorCode WebFetchToolResultErrorCode`

          - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

          - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

          - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

          - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

          - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

          - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

          - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

          - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

          - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

        - `Type WebFetchToolResultError`

          - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

      - `type WebFetchBlockParamResp struct{…}`

        - `Content DocumentBlockParamResp`

        - `Type WebFetchResult`

          - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

        - `URL string`

          Fetched content URL

        - `RetrievedAt string`

          ISO 8601 timestamp when the content was retrieved

    - `ToolUseID string`

    - `Type WebFetchToolResult`

      - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Caller WebFetchToolResultBlockParamCallerUnionResp`

      Tool invocation directly from the model.

      - `type DirectCaller struct{…}`

        Tool invocation directly from the model.

      - `type ServerToolCaller struct{…}`

        Tool invocation generated by a server-side tool.

      - `type ServerToolCaller20260120 struct{…}`

  - `type CodeExecutionToolResultBlockParamResp struct{…}`

    - `Content CodeExecutionToolResultBlockParamContentUnionResp`

      Code execution result with encrypted stdout for PFC + web_search results.

      - `type CodeExecutionToolResultErrorParamResp struct{…}`

        - `ErrorCode CodeExecutionToolResultErrorCode`

          - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

          - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

          - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

          - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

        - `Type CodeExecutionToolResultError`

          - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

      - `type CodeExecutionResultBlockParamResp struct{…}`

        - `Content []CodeExecutionOutputBlockParamResp`

          - `FileID string`

          - `Type CodeExecutionOutput`

            - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

        - `ReturnCode int64`

        - `Stderr string`

        - `Stdout string`

        - `Type CodeExecutionResult`

          - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

      - `type EncryptedCodeExecutionResultBlockParamResp struct{…}`

        Code execution result with encrypted stdout for PFC + web_search results.

        - `Content []CodeExecutionOutputBlockParamResp`

          - `FileID string`

          - `Type CodeExecutionOutput`

        - `EncryptedStdout string`

        - `ReturnCode int64`

        - `Stderr string`

        - `Type EncryptedCodeExecutionResult`

          - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

    - `ToolUseID string`

    - `Type CodeExecutionToolResult`

      - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

  - `type BashCodeExecutionToolResultBlockParamResp struct{…}`

    - `Content BashCodeExecutionToolResultBlockParamContentUnionResp`

      - `type BashCodeExecutionToolResultErrorParamResp struct{…}`

        - `ErrorCode BashCodeExecutionToolResultErrorCode`

          - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

          - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

          - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

          - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

          - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

        - `Type BashCodeExecutionToolResultError`

          - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

      - `type BashCodeExecutionResultBlockParamResp struct{…}`

        - `Content []BashCodeExecutionOutputBlockParamResp`

          - `FileID string`

          - `Type BashCodeExecutionOutput`

            - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

        - `ReturnCode int64`

        - `Stderr string`

        - `Stdout string`

        - `Type BashCodeExecutionResult`

          - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

    - `ToolUseID string`

    - `Type BashCodeExecutionToolResult`

      - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

  - `type TextEditorCodeExecutionToolResultBlockParamResp struct{…}`

    - `Content TextEditorCodeExecutionToolResultBlockParamContentUnionResp`

      - `type TextEditorCodeExecutionToolResultErrorParamResp struct{…}`

        - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

          - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

          - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

          - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

          - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

          - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

        - `Type TextEditorCodeExecutionToolResultError`

          - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

        - `ErrorMessage string`

      - `type TextEditorCodeExecutionViewResultBlockParamResp struct{…}`

        - `Content string`

        - `FileType TextEditorCodeExecutionViewResultBlockParamFileType`

          - `const TextEditorCodeExecutionViewResultBlockParamFileTypeText TextEditorCodeExecutionViewResultBlockParamFileType = "text"`

          - `const TextEditorCodeExecutionViewResultBlockParamFileTypeImage TextEditorCodeExecutionViewResultBlockParamFileType = "image"`

          - `const TextEditorCodeExecutionViewResultBlockParamFileTypePDF TextEditorCodeExecutionViewResultBlockParamFileType = "pdf"`

        - `Type TextEditorCodeExecutionViewResult`

          - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

        - `NumLines int64`

        - `StartLine int64`

        - `TotalLines int64`

      - `type TextEditorCodeExecutionCreateResultBlockParamResp struct{…}`

        - `IsFileUpdate bool`

        - `Type TextEditorCodeExecutionCreateResult`

          - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

      - `type TextEditorCodeExecutionStrReplaceResultBlockParamResp struct{…}`

        - `Type TextEditorCodeExecutionStrReplaceResult`

          - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

        - `Lines []string`

        - `NewLines int64`

        - `NewStart int64`

        - `OldLines int64`

        - `OldStart int64`

    - `ToolUseID string`

    - `Type TextEditorCodeExecutionToolResult`

      - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

  - `type ToolSearchToolResultBlockParamResp struct{…}`

    - `Content ToolSearchToolResultBlockParamContentUnionResp`

      - `type ToolSearchToolResultErrorParamResp struct{…}`

        - `ErrorCode ToolSearchToolResultErrorCode`

          - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

          - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

          - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

          - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

        - `Type ToolSearchToolResultError`

          - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

        - `ErrorMessage string`

      - `type ToolSearchToolSearchResultBlockParamResp struct{…}`

        - `ToolReferences []ToolReferenceBlockParamResp`

          - `ToolName string`

          - `Type ToolReference`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

        - `Type ToolSearchToolSearchResult`

          - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

    - `ToolUseID string`

    - `Type ToolSearchToolResult`

      - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

  - `type ContainerUploadBlockParamResp struct{…}`

    A content block that represents a file to be uploaded to the container
    Files uploaded via this block will be available in the container's input directory.

    - `FileID string`

    - `Type ContainerUpload`

      - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

  - `type MidConversationSystemBlockParamResp struct{…}`

    System instructions that appear mid-conversation.

    Use this block to provide or update system-level instructions at a specific
    point in the conversation, rather than only via the top-level `system` parameter.

    - `Content []TextBlockParamResp`

      System instruction text blocks.

      - `Text string`

      - `Type Text`

      - `CacheControl CacheControlEphemeral`

        Create a cache control breakpoint at this content block.

      - `Citations []TextCitationParamUnionResp`

    - `Type MidConvSystem`

      - `const MidConvSystemMidConvSystem MidConvSystem = "mid_conv_system"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

### Content Block Source

- `type ContentBlockSource struct{…}`

  - `Content ContentBlockSourceContentUnion`

    - `string`

    - `[]ContentBlockSourceContentItemUnion`

      - `type TextBlockParamResp struct{…}`

        - `Text string`

        - `Type Text`

          - `const TextText Text = "text"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

          - `Type Ephemeral`

            - `const EphemeralEphemeral Ephemeral = "ephemeral"`

          - `TTL CacheControlEphemeralTTL`

            The time-to-live for the cache control breakpoint.

            This may be one the following values:

            - `5m`: 5 minutes
            - `1h`: 1 hour

            Defaults to `5m`.

            - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

            - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

        - `Citations []TextCitationParamUnionResp`

          - `type CitationCharLocationParamResp struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndCharIndex int64`

            - `StartCharIndex int64`

            - `Type CharLocation`

              - `const CharLocationCharLocation CharLocation = "char_location"`

          - `type CitationPageLocationParamResp struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndPageNumber int64`

            - `StartPageNumber int64`

            - `Type PageLocation`

              - `const PageLocationPageLocation PageLocation = "page_location"`

          - `type CitationContentBlockLocationParamResp struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Type ContentBlockLocation`

              - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

          - `type CitationWebSearchResultLocationParamResp struct{…}`

            - `CitedText string`

            - `EncryptedIndex string`

            - `Title string`

            - `Type WebSearchResultLocation`

              - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

            - `URL string`

          - `type CitationSearchResultLocationParamResp struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `SearchResultIndex int64`

              0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

              Counted separately from `document_index`; server-side web search results are not included in this count.

            - `Source string`

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Title string`

            - `Type SearchResultLocation`

              - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

      - `type ImageBlockParamResp struct{…}`

        - `Source ImageBlockParamSourceUnionResp`

          - `type Base64ImageSource struct{…}`

            - `Data string`

            - `MediaType Base64ImageSourceMediaType`

              - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

              - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

              - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

              - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

            - `Type Base64`

              - `const Base64Base64 Base64 = "base64"`

          - `type URLImageSource struct{…}`

            - `Type URL`

              - `const URLURL URL = "url"`

            - `URL string`

        - `Type Image`

          - `const ImageImage Image = "image"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

  - `Type Content`

    - `const ContentContent Content = "content"`

### Content Block Source Content

- `type ContentBlockSourceContentItemUnion interface{…}`

  - `type TextBlockParamResp struct{…}`

    - `Text string`

    - `Type Text`

      - `const TextText Text = "text"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

      - `Type Ephemeral`

        - `const EphemeralEphemeral Ephemeral = "ephemeral"`

      - `TTL CacheControlEphemeralTTL`

        The time-to-live for the cache control breakpoint.

        This may be one the following values:

        - `5m`: 5 minutes
        - `1h`: 1 hour

        Defaults to `5m`.

        - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

        - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

    - `Citations []TextCitationParamUnionResp`

      - `type CitationCharLocationParamResp struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndCharIndex int64`

        - `StartCharIndex int64`

        - `Type CharLocation`

          - `const CharLocationCharLocation CharLocation = "char_location"`

      - `type CitationPageLocationParamResp struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndPageNumber int64`

        - `StartPageNumber int64`

        - `Type PageLocation`

          - `const PageLocationPageLocation PageLocation = "page_location"`

      - `type CitationContentBlockLocationParamResp struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Type ContentBlockLocation`

          - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

      - `type CitationWebSearchResultLocationParamResp struct{…}`

        - `CitedText string`

        - `EncryptedIndex string`

        - `Title string`

        - `Type WebSearchResultLocation`

          - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

        - `URL string`

      - `type CitationSearchResultLocationParamResp struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `SearchResultIndex int64`

          0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

          Counted separately from `document_index`; server-side web search results are not included in this count.

        - `Source string`

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Title string`

        - `Type SearchResultLocation`

          - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

  - `type ImageBlockParamResp struct{…}`

    - `Source ImageBlockParamSourceUnionResp`

      - `type Base64ImageSource struct{…}`

        - `Data string`

        - `MediaType Base64ImageSourceMediaType`

          - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

          - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

          - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

          - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

        - `Type Base64`

          - `const Base64Base64 Base64 = "base64"`

      - `type URLImageSource struct{…}`

        - `Type URL`

          - `const URLURL URL = "url"`

        - `URL string`

    - `Type Image`

      - `const ImageImage Image = "image"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

### Direct Caller

- `type DirectCaller struct{…}`

  Tool invocation directly from the model.

  - `Type Direct`

    - `const DirectDirect Direct = "direct"`

### Document Block

- `type DocumentBlock struct{…}`

  - `Citations CitationsConfig`

    Citation configuration for the document

    - `Enabled bool`

  - `Source DocumentBlockSourceUnion`

    - `type Base64PDFSource struct{…}`

      - `Data string`

      - `MediaType ApplicationPDF`

        - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

      - `Type Base64`

        - `const Base64Base64 Base64 = "base64"`

    - `type PlainTextSource struct{…}`

      - `Data string`

      - `MediaType TextPlain`

        - `const TextPlainTextPlain TextPlain = "text/plain"`

      - `Type Text`

        - `const TextText Text = "text"`

  - `Title string`

    The title of the document

  - `Type Document`

    - `const DocumentDocument Document = "document"`

### Document Block Param

- `type DocumentBlockParamResp struct{…}`

  - `Source DocumentBlockParamSourceUnionResp`

    - `type Base64PDFSource struct{…}`

      - `Data string`

      - `MediaType ApplicationPDF`

        - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

      - `Type Base64`

        - `const Base64Base64 Base64 = "base64"`

    - `type PlainTextSource struct{…}`

      - `Data string`

      - `MediaType TextPlain`

        - `const TextPlainTextPlain TextPlain = "text/plain"`

      - `Type Text`

        - `const TextText Text = "text"`

    - `type ContentBlockSource struct{…}`

      - `Content ContentBlockSourceContentUnion`

        - `string`

        - `[]ContentBlockSourceContentItemUnion`

          - `type TextBlockParamResp struct{…}`

            - `Text string`

            - `Type Text`

              - `const TextText Text = "text"`

            - `CacheControl CacheControlEphemeral`

              Create a cache control breakpoint at this content block.

              - `Type Ephemeral`

                - `const EphemeralEphemeral Ephemeral = "ephemeral"`

              - `TTL CacheControlEphemeralTTL`

                The time-to-live for the cache control breakpoint.

                This may be one the following values:

                - `5m`: 5 minutes
                - `1h`: 1 hour

                Defaults to `5m`.

                - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

                - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

            - `Citations []TextCitationParamUnionResp`

              - `type CitationCharLocationParamResp struct{…}`

                - `CitedText string`

                - `DocumentIndex int64`

                - `DocumentTitle string`

                - `EndCharIndex int64`

                - `StartCharIndex int64`

                - `Type CharLocation`

                  - `const CharLocationCharLocation CharLocation = "char_location"`

              - `type CitationPageLocationParamResp struct{…}`

                - `CitedText string`

                - `DocumentIndex int64`

                - `DocumentTitle string`

                - `EndPageNumber int64`

                - `StartPageNumber int64`

                - `Type PageLocation`

                  - `const PageLocationPageLocation PageLocation = "page_location"`

              - `type CitationContentBlockLocationParamResp struct{…}`

                - `CitedText string`

                  The full text of the cited block range, concatenated.

                  Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                - `DocumentIndex int64`

                - `DocumentTitle string`

                - `EndBlockIndex int64`

                  Exclusive 0-based end index of the cited block range in the source's `content` array.

                  Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                - `StartBlockIndex int64`

                  0-based index of the first cited block in the source's `content` array.

                - `Type ContentBlockLocation`

                  - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

              - `type CitationWebSearchResultLocationParamResp struct{…}`

                - `CitedText string`

                - `EncryptedIndex string`

                - `Title string`

                - `Type WebSearchResultLocation`

                  - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

                - `URL string`

              - `type CitationSearchResultLocationParamResp struct{…}`

                - `CitedText string`

                  The full text of the cited block range, concatenated.

                  Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                - `EndBlockIndex int64`

                  Exclusive 0-based end index of the cited block range in the source's `content` array.

                  Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                - `SearchResultIndex int64`

                  0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                  Counted separately from `document_index`; server-side web search results are not included in this count.

                - `Source string`

                - `StartBlockIndex int64`

                  0-based index of the first cited block in the source's `content` array.

                - `Title string`

                - `Type SearchResultLocation`

                  - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

          - `type ImageBlockParamResp struct{…}`

            - `Source ImageBlockParamSourceUnionResp`

              - `type Base64ImageSource struct{…}`

                - `Data string`

                - `MediaType Base64ImageSourceMediaType`

                  - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

                  - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

                  - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

                  - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

                - `Type Base64`

                  - `const Base64Base64 Base64 = "base64"`

              - `type URLImageSource struct{…}`

                - `Type URL`

                  - `const URLURL URL = "url"`

                - `URL string`

            - `Type Image`

              - `const ImageImage Image = "image"`

            - `CacheControl CacheControlEphemeral`

              Create a cache control breakpoint at this content block.

      - `Type Content`

        - `const ContentContent Content = "content"`

    - `type URLPDFSource struct{…}`

      - `Type URL`

        - `const URLURL URL = "url"`

      - `URL string`

  - `Type Document`

    - `const DocumentDocument Document = "document"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

  - `Citations CitationsConfigParamResp`

    - `Enabled bool`

  - `Context string`

  - `Title string`

### Encrypted Code Execution Result Block

- `type EncryptedCodeExecutionResultBlock struct{…}`

  Code execution result with encrypted stdout for PFC + web_search results.

  - `Content []CodeExecutionOutputBlock`

    - `FileID string`

    - `Type CodeExecutionOutput`

      - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

  - `EncryptedStdout string`

  - `ReturnCode int64`

  - `Stderr string`

  - `Type EncryptedCodeExecutionResult`

    - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

### Encrypted Code Execution Result Block Param

- `type EncryptedCodeExecutionResultBlockParamResp struct{…}`

  Code execution result with encrypted stdout for PFC + web_search results.

  - `Content []CodeExecutionOutputBlockParamResp`

    - `FileID string`

    - `Type CodeExecutionOutput`

      - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

  - `EncryptedStdout string`

  - `ReturnCode int64`

  - `Stderr string`

  - `Type EncryptedCodeExecutionResult`

    - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

### Image Block Param

- `type ImageBlockParamResp struct{…}`

  - `Source ImageBlockParamSourceUnionResp`

    - `type Base64ImageSource struct{…}`

      - `Data string`

      - `MediaType Base64ImageSourceMediaType`

        - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

        - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

        - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

        - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

      - `Type Base64`

        - `const Base64Base64 Base64 = "base64"`

    - `type URLImageSource struct{…}`

      - `Type URL`

        - `const URLURL URL = "url"`

      - `URL string`

  - `Type Image`

    - `const ImageImage Image = "image"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

### Input JSON Delta

- `type InputJSONDelta struct{…}`

  - `PartialJSON string`

  - `Type InputJSONDelta`

    - `const InputJSONDeltaInputJSONDelta InputJSONDelta = "input_json_delta"`

### JSON Output Format

- `type JSONOutputFormat struct{…}`

  - `Schema map[string, any]`

    The JSON schema of the format

  - `Type JSONSchema`

    - `const JSONSchemaJSONSchema JSONSchema = "json_schema"`

### Memory Tool 20250818

- `type MemoryTool20250818 struct{…}`

  - `Name Memory`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const MemoryMemory Memory = "memory"`

  - `Type Memory20250818`

    - `const Memory20250818Memory20250818 Memory20250818 = "memory_20250818"`

  - `AllowedCallers []string`

    - `const MemoryTool20250818AllowedCallerDirect MemoryTool20250818AllowedCaller = "direct"`

    - `const MemoryTool20250818AllowedCallerCodeExecution20250825 MemoryTool20250818AllowedCaller = "code_execution_20250825"`

    - `const MemoryTool20250818AllowedCallerCodeExecution20260120 MemoryTool20250818AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `InputExamples []map[string, any]`

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Message

- `type Message struct{…}`

  - `ID string`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `Container Container`

    Information about the container used in the request (for the code execution tool)

    - `ID string`

      Identifier for the container used in this request

    - `ExpiresAt Time`

      The time at which the container will expire.

  - `Content []ContentBlockUnion`

    Content generated by the model.

    This is an array of content blocks, each of which has a `type` that determines its shape.

    Example:

    ```json
    [{"type": "text", "text": "Hi, I'm Claude."}]
    ```

    If the request input `messages` ended with an `assistant` turn, then the response `content` will continue directly from that last turn. You can use this to constrain the model's output.

    For example, if the input `messages` were:

    ```json
    [
      {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
      {"role": "assistant", "content": "The best answer is ("}
    ]
    ```

    Then the response `content` might be:

    ```json
    [{"type": "text", "text": "B)"}]
    ```

    - `type TextBlock struct{…}`

      - `Citations []TextCitationUnion`

        Citations supporting the text block.

        The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

        - `type CitationCharLocation struct{…}`

          - `CitedText string`

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndCharIndex int64`

          - `FileID string`

          - `StartCharIndex int64`

          - `Type CharLocation`

            - `const CharLocationCharLocation CharLocation = "char_location"`

        - `type CitationPageLocation struct{…}`

          - `CitedText string`

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndPageNumber int64`

          - `FileID string`

          - `StartPageNumber int64`

          - `Type PageLocation`

            - `const PageLocationPageLocation PageLocation = "page_location"`

        - `type CitationContentBlockLocation struct{…}`

          - `CitedText string`

            The full text of the cited block range, concatenated.

            Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndBlockIndex int64`

            Exclusive 0-based end index of the cited block range in the source's `content` array.

            Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

          - `FileID string`

          - `StartBlockIndex int64`

            0-based index of the first cited block in the source's `content` array.

          - `Type ContentBlockLocation`

            - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

        - `type CitationsWebSearchResultLocation struct{…}`

          - `CitedText string`

          - `EncryptedIndex string`

          - `Title string`

          - `Type WebSearchResultLocation`

            - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

          - `URL string`

        - `type CitationsSearchResultLocation struct{…}`

          - `CitedText string`

            The full text of the cited block range, concatenated.

            Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

          - `EndBlockIndex int64`

            Exclusive 0-based end index of the cited block range in the source's `content` array.

            Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

          - `SearchResultIndex int64`

            0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

            Counted separately from `document_index`; server-side web search results are not included in this count.

          - `Source string`

          - `StartBlockIndex int64`

            0-based index of the first cited block in the source's `content` array.

          - `Title string`

          - `Type SearchResultLocation`

            - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

      - `Text string`

      - `Type Text`

        - `const TextText Text = "text"`

    - `type ThinkingBlock struct{…}`

      - `Signature string`

      - `Thinking string`

      - `Type Thinking`

        - `const ThinkingThinking Thinking = "thinking"`

    - `type RedactedThinkingBlock struct{…}`

      - `Data string`

      - `Type RedactedThinking`

        - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

    - `type ToolUseBlock struct{…}`

      - `ID string`

      - `Caller ToolUseBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

          - `Type Direct`

            - `const DirectDirect Direct = "direct"`

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

          - `ToolID string`

          - `Type CodeExecution20250825`

            - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

        - `type ServerToolCaller20260120 struct{…}`

          - `ToolID string`

          - `Type CodeExecution20260120`

            - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

      - `Input map[string, any]`

      - `Name string`

      - `Type ToolUse`

        - `const ToolUseToolUse ToolUse = "tool_use"`

    - `type ServerToolUseBlock struct{…}`

      - `ID string`

      - `Caller ServerToolUseBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

        - `type ServerToolCaller20260120 struct{…}`

      - `Input map[string, any]`

      - `Name ServerToolUseBlockName`

        - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

        - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

        - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

        - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

        - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

        - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

        - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

      - `Type ServerToolUse`

        - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

    - `type WebSearchToolResultBlock struct{…}`

      - `Caller WebSearchToolResultBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

        - `type ServerToolCaller20260120 struct{…}`

      - `Content WebSearchToolResultBlockContentUnion`

        - `type WebSearchToolResultError struct{…}`

          - `ErrorCode WebSearchToolResultErrorCode`

            - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

            - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

            - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

            - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

            - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

            - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

          - `Type WebSearchToolResultError`

            - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

        - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

          - `EncryptedContent string`

          - `PageAge string`

          - `Title string`

          - `Type WebSearchResult`

            - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

          - `URL string`

      - `ToolUseID string`

      - `Type WebSearchToolResult`

        - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

    - `type WebFetchToolResultBlock struct{…}`

      - `Caller WebFetchToolResultBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

        - `type ServerToolCaller20260120 struct{…}`

      - `Content WebFetchToolResultBlockContentUnion`

        - `type WebFetchToolResultErrorBlock struct{…}`

          - `ErrorCode WebFetchToolResultErrorCode`

            - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

            - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

            - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

            - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

            - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

            - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

            - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

            - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

            - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

          - `Type WebFetchToolResultError`

            - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

        - `type WebFetchBlock struct{…}`

          - `Content DocumentBlock`

            - `Citations CitationsConfig`

              Citation configuration for the document

              - `Enabled bool`

            - `Source DocumentBlockSourceUnion`

              - `type Base64PDFSource struct{…}`

                - `Data string`

                - `MediaType ApplicationPDF`

                  - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                - `Type Base64`

                  - `const Base64Base64 Base64 = "base64"`

              - `type PlainTextSource struct{…}`

                - `Data string`

                - `MediaType TextPlain`

                  - `const TextPlainTextPlain TextPlain = "text/plain"`

                - `Type Text`

                  - `const TextText Text = "text"`

            - `Title string`

              The title of the document

            - `Type Document`

              - `const DocumentDocument Document = "document"`

          - `RetrievedAt string`

            ISO 8601 timestamp when the content was retrieved

          - `Type WebFetchResult`

            - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

          - `URL string`

            Fetched content URL

      - `ToolUseID string`

      - `Type WebFetchToolResult`

        - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

    - `type CodeExecutionToolResultBlock struct{…}`

      - `Content CodeExecutionToolResultBlockContentUnion`

        Code execution result with encrypted stdout for PFC + web_search results.

        - `type CodeExecutionToolResultError struct{…}`

          - `ErrorCode CodeExecutionToolResultErrorCode`

            - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

            - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

            - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

            - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

          - `Type CodeExecutionToolResultError`

            - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

        - `type CodeExecutionResultBlock struct{…}`

          - `Content []CodeExecutionOutputBlock`

            - `FileID string`

            - `Type CodeExecutionOutput`

              - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

          - `ReturnCode int64`

          - `Stderr string`

          - `Stdout string`

          - `Type CodeExecutionResult`

            - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

        - `type EncryptedCodeExecutionResultBlock struct{…}`

          Code execution result with encrypted stdout for PFC + web_search results.

          - `Content []CodeExecutionOutputBlock`

            - `FileID string`

            - `Type CodeExecutionOutput`

          - `EncryptedStdout string`

          - `ReturnCode int64`

          - `Stderr string`

          - `Type EncryptedCodeExecutionResult`

            - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

      - `ToolUseID string`

      - `Type CodeExecutionToolResult`

        - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

    - `type BashCodeExecutionToolResultBlock struct{…}`

      - `Content BashCodeExecutionToolResultBlockContentUnion`

        - `type BashCodeExecutionToolResultError struct{…}`

          - `ErrorCode BashCodeExecutionToolResultErrorCode`

            - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

            - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

            - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

            - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

            - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

          - `Type BashCodeExecutionToolResultError`

            - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

        - `type BashCodeExecutionResultBlock struct{…}`

          - `Content []BashCodeExecutionOutputBlock`

            - `FileID string`

            - `Type BashCodeExecutionOutput`

              - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

          - `ReturnCode int64`

          - `Stderr string`

          - `Stdout string`

          - `Type BashCodeExecutionResult`

            - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

      - `ToolUseID string`

      - `Type BashCodeExecutionToolResult`

        - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

    - `type TextEditorCodeExecutionToolResultBlock struct{…}`

      - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

        - `type TextEditorCodeExecutionToolResultError struct{…}`

          - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

            - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

            - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

            - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

            - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

            - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

          - `ErrorMessage string`

          - `Type TextEditorCodeExecutionToolResultError`

            - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

        - `type TextEditorCodeExecutionViewResultBlock struct{…}`

          - `Content string`

          - `FileType TextEditorCodeExecutionViewResultBlockFileType`

            - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

            - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

            - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

          - `NumLines int64`

          - `StartLine int64`

          - `TotalLines int64`

          - `Type TextEditorCodeExecutionViewResult`

            - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

        - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

          - `IsFileUpdate bool`

          - `Type TextEditorCodeExecutionCreateResult`

            - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

        - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

          - `Lines []string`

          - `NewLines int64`

          - `NewStart int64`

          - `OldLines int64`

          - `OldStart int64`

          - `Type TextEditorCodeExecutionStrReplaceResult`

            - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

      - `ToolUseID string`

      - `Type TextEditorCodeExecutionToolResult`

        - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

    - `type ToolSearchToolResultBlock struct{…}`

      - `Content ToolSearchToolResultBlockContentUnion`

        - `type ToolSearchToolResultError struct{…}`

          - `ErrorCode ToolSearchToolResultErrorCode`

            - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

            - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

            - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

            - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

          - `ErrorMessage string`

          - `Type ToolSearchToolResultError`

            - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

        - `type ToolSearchToolSearchResultBlock struct{…}`

          - `ToolReferences []ToolReferenceBlock`

            - `ToolName string`

            - `Type ToolReference`

              - `const ToolReferenceToolReference ToolReference = "tool_reference"`

          - `Type ToolSearchToolSearchResult`

            - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

      - `ToolUseID string`

      - `Type ToolSearchToolResult`

        - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

    - `type ContainerUploadBlock struct{…}`

      Response model for a file uploaded to the container.

      - `FileID string`

      - `Type ContainerUpload`

        - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

  - `Model Model`

    The model that will complete your prompt.

    See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

    - `type Model string`

      The model that will complete your prompt.

      See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

      - `const ModelClaudeFable5 Model = "claude-fable-5"`

        Next generation of intelligence for the hardest knowledge work and coding problems

      - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

        Most capable model for cybersecurity and biology research

      - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

        Frontier intelligence for long-running agents and coding

      - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

        Frontier intelligence for long-running agents and coding

      - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

        New class of intelligence, strongest in coding and cybersecurity

      - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

        Frontier intelligence for long-running agents and coding

      - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

        Best combination of speed and intelligence

      - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

        Fastest model with near-frontier intelligence

      - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

        Fastest model with near-frontier intelligence

      - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

        Premium model combining maximum intelligence with practical performance

      - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

        Premium model combining maximum intelligence with practical performance

      - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

        High-performance model for agents and coding

      - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

        High-performance model for agents and coding

      - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

        Exceptional model for specialized complex tasks

      - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

        Exceptional model for specialized complex tasks

      - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

        Powerful model for complex tasks

      - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

        Powerful model for complex tasks

      - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

        High-performance model with extended thinking

      - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

        High-performance model with extended thinking

      - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

        Fast and cost-effective model

    - `string`

  - `Role Assistant`

    Conversational role of the generated message.

    This will always be `"assistant"`.

    - `const AssistantAssistant Assistant = "assistant"`

  - `StopDetails RefusalStopDetails`

    Structured information about a refusal.

    - `Category RefusalStopDetailsCategory`

      The policy category that triggered the refusal.

      `null` when the refusal doesn't map to a named category.

      - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

      - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

      - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

    - `Explanation string`

      Human-readable explanation of the refusal.

      This text is not guaranteed to be stable. `null` when no explanation is available for the category.

    - `Type Refusal`

      - `const RefusalRefusal Refusal = "refusal"`

  - `StopReason StopReason`

    The reason that we stopped.

    This may be one the following values:

    * `"end_turn"`: the model reached a natural stopping point
    * `"max_tokens"`: we exceeded the requested `max_tokens` or the model's maximum
    * `"stop_sequence"`: one of your provided custom `stop_sequences` was generated
    * `"tool_use"`: the model invoked one or more tools
    * `"pause_turn"`: we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
    * `"refusal"`: when streaming classifiers intervene to handle potential policy violations

    In non-streaming mode this value is always non-null. In streaming mode, it is null in the `message_start` event and non-null otherwise.

    - `const StopReasonEndTurn StopReason = "end_turn"`

    - `const StopReasonMaxTokens StopReason = "max_tokens"`

    - `const StopReasonStopSequence StopReason = "stop_sequence"`

    - `const StopReasonToolUse StopReason = "tool_use"`

    - `const StopReasonPauseTurn StopReason = "pause_turn"`

    - `const StopReasonRefusal StopReason = "refusal"`

  - `StopSequence string`

    Which custom stop sequence was generated, if any.

    This value will be a non-null string if one of your custom stop sequences was generated.

  - `Type Message`

    Object type.

    For Messages, this is always `"message"`.

    - `const MessageMessage Message = "message"`

  - `Usage Usage`

    Billing and rate-limit usage.

    Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

    Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

    For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

    Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

    - `CacheCreation CacheCreation`

      Breakdown of cached tokens by TTL

      - `Ephemeral1hInputTokens int64`

        The number of input tokens used to create the 1 hour cache entry.

      - `Ephemeral5mInputTokens int64`

        The number of input tokens used to create the 5 minute cache entry.

    - `CacheCreationInputTokens int64`

      The number of input tokens used to create the cache entry.

    - `CacheReadInputTokens int64`

      The number of input tokens read from the cache.

    - `InferenceGeo string`

      The geographic region where inference was performed for this request.

    - `InputTokens int64`

      The number of input tokens which were used.

    - `OutputTokens int64`

      The number of output tokens which were used.

    - `OutputTokensDetails OutputTokensDetails`

      Breakdown of output tokens by category.

      `output_tokens` remains the inclusive, authoritative total used for billing.
      This object provides a read-only decomposition for observability — for example,
      how many of the billed output tokens were spent on internal reasoning that may
      have been summarized before being returned to you.

      - `ThinkingTokens int64`

        Number of output tokens the model generated as internal reasoning, including
        the thinking-block delimiter tokens.

        Reflects the raw reasoning the model produced, not the (possibly shorter)
        summarized thinking text returned in the response body. Computed by
        re-tokenizing the raw reasoning text, so it may differ from the model's exact
        generation count by a small number of tokens. Always ≤ `output_tokens`;
        `output_tokens - thinking_tokens` approximates the non-reasoning output.

    - `ServerToolUse ServerToolUsage`

      The number of server tool requests.

      - `WebFetchRequests int64`

        The number of web fetch tool requests.

      - `WebSearchRequests int64`

        The number of web search tool requests.

    - `ServiceTier UsageServiceTier`

      If the request used the priority, standard, or batch tier.

      - `const UsageServiceTierStandard UsageServiceTier = "standard"`

      - `const UsageServiceTierPriority UsageServiceTier = "priority"`

      - `const UsageServiceTierBatch UsageServiceTier = "batch"`

### Message Count Tokens Tool

- `type MessageCountTokensToolUnion interface{…}`

  Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

  - `type Tool struct{…}`

    - `InputSchema ToolInputSchema`

      [JSON schema](https://json-schema.org/draft/2020-12) for this tool's input.

      This defines the shape of the `input` that your tool accepts and that the model will produce.

      - `Type Object`

        - `const ObjectObject Object = "object"`

      - `Properties map[string, any]`

      - `Required []string`

    - `Name string`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

    - `AllowedCallers []string`

      - `const ToolAllowedCallerDirect ToolAllowedCaller = "direct"`

      - `const ToolAllowedCallerCodeExecution20250825 ToolAllowedCaller = "code_execution_20250825"`

      - `const ToolAllowedCallerCodeExecution20260120 ToolAllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

      - `Type Ephemeral`

        - `const EphemeralEphemeral Ephemeral = "ephemeral"`

      - `TTL CacheControlEphemeralTTL`

        The time-to-live for the cache control breakpoint.

        This may be one the following values:

        - `5m`: 5 minutes
        - `1h`: 1 hour

        Defaults to `5m`.

        - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

        - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Description string`

      Description of what this tool does.

      Tool descriptions should be as detailed as possible. The more information that the model has about what the tool is and how to use it, the better it will perform. You can use natural language descriptions to reinforce important aspects of the tool input JSON schema.

    - `EagerInputStreaming bool`

      Enable eager input streaming for this tool. When true, tool input parameters will be streamed incrementally as they are generated, and types will be inferred on-the-fly rather than buffering the full JSON output. When false, streaming is disabled for this tool even if the fine-grained-tool-streaming beta is active. When null (default), uses the default behavior based on beta headers.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

    - `Type ToolType`

      - `const ToolTypeCustom ToolType = "custom"`

  - `type ToolBash20250124 struct{…}`

    - `Name Bash`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const BashBash Bash = "bash"`

    - `Type Bash20250124`

      - `const Bash20250124Bash20250124 Bash20250124 = "bash_20250124"`

    - `AllowedCallers []string`

      - `const ToolBash20250124AllowedCallerDirect ToolBash20250124AllowedCaller = "direct"`

      - `const ToolBash20250124AllowedCallerCodeExecution20250825 ToolBash20250124AllowedCaller = "code_execution_20250825"`

      - `const ToolBash20250124AllowedCallerCodeExecution20260120 ToolBash20250124AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type CodeExecutionTool20250522 struct{…}`

    - `Name CodeExecution`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

    - `Type CodeExecution20250522`

      - `const CodeExecution20250522CodeExecution20250522 CodeExecution20250522 = "code_execution_20250522"`

    - `AllowedCallers []string`

      - `const CodeExecutionTool20250522AllowedCallerDirect CodeExecutionTool20250522AllowedCaller = "direct"`

      - `const CodeExecutionTool20250522AllowedCallerCodeExecution20250825 CodeExecutionTool20250522AllowedCaller = "code_execution_20250825"`

      - `const CodeExecutionTool20250522AllowedCallerCodeExecution20260120 CodeExecutionTool20250522AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type CodeExecutionTool20250825 struct{…}`

    - `Name CodeExecution`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

    - `Type CodeExecution20250825`

      - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `AllowedCallers []string`

      - `const CodeExecutionTool20250825AllowedCallerDirect CodeExecutionTool20250825AllowedCaller = "direct"`

      - `const CodeExecutionTool20250825AllowedCallerCodeExecution20250825 CodeExecutionTool20250825AllowedCaller = "code_execution_20250825"`

      - `const CodeExecutionTool20250825AllowedCallerCodeExecution20260120 CodeExecutionTool20250825AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type CodeExecutionTool20260120 struct{…}`

    Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

    - `Name CodeExecution`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

    - `Type CodeExecution20260120`

      - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

    - `AllowedCallers []string`

      - `const CodeExecutionTool20260120AllowedCallerDirect CodeExecutionTool20260120AllowedCaller = "direct"`

      - `const CodeExecutionTool20260120AllowedCallerCodeExecution20250825 CodeExecutionTool20260120AllowedCaller = "code_execution_20250825"`

      - `const CodeExecutionTool20260120AllowedCallerCodeExecution20260120 CodeExecutionTool20260120AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type MemoryTool20250818 struct{…}`

    - `Name Memory`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const MemoryMemory Memory = "memory"`

    - `Type Memory20250818`

      - `const Memory20250818Memory20250818 Memory20250818 = "memory_20250818"`

    - `AllowedCallers []string`

      - `const MemoryTool20250818AllowedCallerDirect MemoryTool20250818AllowedCaller = "direct"`

      - `const MemoryTool20250818AllowedCallerCodeExecution20250825 MemoryTool20250818AllowedCaller = "code_execution_20250825"`

      - `const MemoryTool20250818AllowedCallerCodeExecution20260120 MemoryTool20250818AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type ToolTextEditor20250124 struct{…}`

    - `Name StrReplaceEditor`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const StrReplaceEditorStrReplaceEditor StrReplaceEditor = "str_replace_editor"`

    - `Type TextEditor20250124`

      - `const TextEditor20250124TextEditor20250124 TextEditor20250124 = "text_editor_20250124"`

    - `AllowedCallers []string`

      - `const ToolTextEditor20250124AllowedCallerDirect ToolTextEditor20250124AllowedCaller = "direct"`

      - `const ToolTextEditor20250124AllowedCallerCodeExecution20250825 ToolTextEditor20250124AllowedCaller = "code_execution_20250825"`

      - `const ToolTextEditor20250124AllowedCallerCodeExecution20260120 ToolTextEditor20250124AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type ToolTextEditor20250429 struct{…}`

    - `Name StrReplaceBasedEditTool`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

    - `Type TextEditor20250429`

      - `const TextEditor20250429TextEditor20250429 TextEditor20250429 = "text_editor_20250429"`

    - `AllowedCallers []string`

      - `const ToolTextEditor20250429AllowedCallerDirect ToolTextEditor20250429AllowedCaller = "direct"`

      - `const ToolTextEditor20250429AllowedCallerCodeExecution20250825 ToolTextEditor20250429AllowedCaller = "code_execution_20250825"`

      - `const ToolTextEditor20250429AllowedCallerCodeExecution20260120 ToolTextEditor20250429AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type ToolTextEditor20250728 struct{…}`

    - `Name StrReplaceBasedEditTool`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

    - `Type TextEditor20250728`

      - `const TextEditor20250728TextEditor20250728 TextEditor20250728 = "text_editor_20250728"`

    - `AllowedCallers []string`

      - `const ToolTextEditor20250728AllowedCallerDirect ToolTextEditor20250728AllowedCaller = "direct"`

      - `const ToolTextEditor20250728AllowedCallerCodeExecution20250825 ToolTextEditor20250728AllowedCaller = "code_execution_20250825"`

      - `const ToolTextEditor20250728AllowedCallerCodeExecution20260120 ToolTextEditor20250728AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `MaxCharacters int64`

      Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type WebSearchTool20250305 struct{…}`

    - `Name WebSearch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebSearchWebSearch WebSearch = "web_search"`

    - `Type WebSearch20250305`

      - `const WebSearch20250305WebSearch20250305 WebSearch20250305 = "web_search_20250305"`

    - `AllowedCallers []string`

      - `const WebSearchTool20250305AllowedCallerDirect WebSearchTool20250305AllowedCaller = "direct"`

      - `const WebSearchTool20250305AllowedCallerCodeExecution20250825 WebSearchTool20250305AllowedCaller = "code_execution_20250825"`

      - `const WebSearchTool20250305AllowedCallerCodeExecution20260120 WebSearchTool20250305AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

    - `BlockedDomains []string`

      If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

    - `UserLocation UserLocation`

      Parameters for the user's location. Used to provide more relevant search results.

      - `Type Approximate`

        - `const ApproximateApproximate Approximate = "approximate"`

      - `City string`

        The city of the user.

      - `Country string`

        The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user.

      - `Region string`

        The region of the user.

      - `Timezone string`

        The [IANA timezone](https://nodatime.org/TimeZones) of the user.

  - `type WebFetchTool20250910 struct{…}`

    - `Name WebFetch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebFetchWebFetch WebFetch = "web_fetch"`

    - `Type WebFetch20250910`

      - `const WebFetch20250910WebFetch20250910 WebFetch20250910 = "web_fetch_20250910"`

    - `AllowedCallers []string`

      - `const WebFetchTool20250910AllowedCallerDirect WebFetchTool20250910AllowedCaller = "direct"`

      - `const WebFetchTool20250910AllowedCallerCodeExecution20250825 WebFetchTool20250910AllowedCaller = "code_execution_20250825"`

      - `const WebFetchTool20250910AllowedCallerCodeExecution20260120 WebFetchTool20250910AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      List of domains to allow fetching from

    - `BlockedDomains []string`

      List of domains to block fetching from

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Citations CitationsConfigParamResp`

      Citations configuration for fetched documents. Citations are disabled by default.

      - `Enabled bool`

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxContentTokens int64`

      Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type WebSearchTool20260209 struct{…}`

    - `Name WebSearch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebSearchWebSearch WebSearch = "web_search"`

    - `Type WebSearch20260209`

      - `const WebSearch20260209WebSearch20260209 WebSearch20260209 = "web_search_20260209"`

    - `AllowedCallers []string`

      - `const WebSearchTool20260209AllowedCallerDirect WebSearchTool20260209AllowedCaller = "direct"`

      - `const WebSearchTool20260209AllowedCallerCodeExecution20250825 WebSearchTool20260209AllowedCaller = "code_execution_20250825"`

      - `const WebSearchTool20260209AllowedCallerCodeExecution20260120 WebSearchTool20260209AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

    - `BlockedDomains []string`

      If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

    - `UserLocation UserLocation`

      Parameters for the user's location. Used to provide more relevant search results.

  - `type WebFetchTool20260209 struct{…}`

    - `Name WebFetch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebFetchWebFetch WebFetch = "web_fetch"`

    - `Type WebFetch20260209`

      - `const WebFetch20260209WebFetch20260209 WebFetch20260209 = "web_fetch_20260209"`

    - `AllowedCallers []string`

      - `const WebFetchTool20260209AllowedCallerDirect WebFetchTool20260209AllowedCaller = "direct"`

      - `const WebFetchTool20260209AllowedCallerCodeExecution20250825 WebFetchTool20260209AllowedCaller = "code_execution_20250825"`

      - `const WebFetchTool20260209AllowedCallerCodeExecution20260120 WebFetchTool20260209AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      List of domains to allow fetching from

    - `BlockedDomains []string`

      List of domains to block fetching from

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Citations CitationsConfigParamResp`

      Citations configuration for fetched documents. Citations are disabled by default.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxContentTokens int64`

      Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type WebFetchTool20260309 struct{…}`

    Web fetch tool with use_cache parameter for bypassing cached content.

    - `Name WebFetch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebFetchWebFetch WebFetch = "web_fetch"`

    - `Type WebFetch20260309`

      - `const WebFetch20260309WebFetch20260309 WebFetch20260309 = "web_fetch_20260309"`

    - `AllowedCallers []string`

      - `const WebFetchTool20260309AllowedCallerDirect WebFetchTool20260309AllowedCaller = "direct"`

      - `const WebFetchTool20260309AllowedCallerCodeExecution20250825 WebFetchTool20260309AllowedCaller = "code_execution_20250825"`

      - `const WebFetchTool20260309AllowedCallerCodeExecution20260120 WebFetchTool20260309AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      List of domains to allow fetching from

    - `BlockedDomains []string`

      List of domains to block fetching from

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Citations CitationsConfigParamResp`

      Citations configuration for fetched documents. Citations are disabled by default.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxContentTokens int64`

      Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

    - `UseCache bool`

      Whether to use cached content. Set to false to bypass the cache and fetch fresh content. Only set to false when the user explicitly requests fresh content or when fetching rapidly-changing sources.

  - `type ToolSearchToolBm25_20251119 struct{…}`

    - `Name ToolSearchToolBm25`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const ToolSearchToolBm25ToolSearchToolBm25 ToolSearchToolBm25 = "tool_search_tool_bm25"`

    - `Type ToolSearchToolBm25_20251119Type`

      - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25_20251119 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25_20251119"`

      - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25"`

    - `AllowedCallers []string`

      - `const ToolSearchToolBm25_20251119AllowedCallerDirect ToolSearchToolBm25_20251119AllowedCaller = "direct"`

      - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20250825 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20250825"`

      - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20260120 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type ToolSearchToolRegex20251119 struct{…}`

    - `Name ToolSearchToolRegex`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const ToolSearchToolRegexToolSearchToolRegex ToolSearchToolRegex = "tool_search_tool_regex"`

    - `Type ToolSearchToolRegex20251119Type`

      - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex20251119 ToolSearchToolRegex20251119Type = "tool_search_tool_regex_20251119"`

      - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex ToolSearchToolRegex20251119Type = "tool_search_tool_regex"`

    - `AllowedCallers []string`

      - `const ToolSearchToolRegex20251119AllowedCallerDirect ToolSearchToolRegex20251119AllowedCaller = "direct"`

      - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20250825 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20250825"`

      - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20260120 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

### Message Delta Usage

- `type MessageDeltaUsage struct{…}`

  - `CacheCreationInputTokens int64`

    The cumulative number of input tokens used to create the cache entry.

  - `CacheReadInputTokens int64`

    The cumulative number of input tokens read from the cache.

  - `InputTokens int64`

    The cumulative number of input tokens which were used.

  - `OutputTokens int64`

    The cumulative number of output tokens which were used.

  - `OutputTokensDetails OutputTokensDetails`

    Breakdown of output tokens by category.

    `output_tokens` remains the inclusive, authoritative total used for billing.
    This object provides a read-only decomposition for observability — for example,
    how many of the billed output tokens were spent on internal reasoning that may
    have been summarized before being returned to you.

    - `ThinkingTokens int64`

      Number of output tokens the model generated as internal reasoning, including
      the thinking-block delimiter tokens.

      Reflects the raw reasoning the model produced, not the (possibly shorter)
      summarized thinking text returned in the response body. Computed by
      re-tokenizing the raw reasoning text, so it may differ from the model's exact
      generation count by a small number of tokens. Always ≤ `output_tokens`;
      `output_tokens - thinking_tokens` approximates the non-reasoning output.

  - `ServerToolUse ServerToolUsage`

    The number of server tool requests.

    - `WebFetchRequests int64`

      The number of web fetch tool requests.

    - `WebSearchRequests int64`

      The number of web search tool requests.

### Message Param

- `type MessageParamResp struct{…}`

  - `Content []ContentBlockParamUnionResp`

    - `[]ContentBlockParamUnionResp`

      - `type TextBlockParamResp struct{…}`

        - `Text string`

        - `Type Text`

          - `const TextText Text = "text"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

          - `Type Ephemeral`

            - `const EphemeralEphemeral Ephemeral = "ephemeral"`

          - `TTL CacheControlEphemeralTTL`

            The time-to-live for the cache control breakpoint.

            This may be one the following values:

            - `5m`: 5 minutes
            - `1h`: 1 hour

            Defaults to `5m`.

            - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

            - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

        - `Citations []TextCitationParamUnionResp`

          - `type CitationCharLocationParamResp struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndCharIndex int64`

            - `StartCharIndex int64`

            - `Type CharLocation`

              - `const CharLocationCharLocation CharLocation = "char_location"`

          - `type CitationPageLocationParamResp struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndPageNumber int64`

            - `StartPageNumber int64`

            - `Type PageLocation`

              - `const PageLocationPageLocation PageLocation = "page_location"`

          - `type CitationContentBlockLocationParamResp struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Type ContentBlockLocation`

              - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

          - `type CitationWebSearchResultLocationParamResp struct{…}`

            - `CitedText string`

            - `EncryptedIndex string`

            - `Title string`

            - `Type WebSearchResultLocation`

              - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

            - `URL string`

          - `type CitationSearchResultLocationParamResp struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `SearchResultIndex int64`

              0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

              Counted separately from `document_index`; server-side web search results are not included in this count.

            - `Source string`

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Title string`

            - `Type SearchResultLocation`

              - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

      - `type ImageBlockParamResp struct{…}`

        - `Source ImageBlockParamSourceUnionResp`

          - `type Base64ImageSource struct{…}`

            - `Data string`

            - `MediaType Base64ImageSourceMediaType`

              - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

              - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

              - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

              - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

            - `Type Base64`

              - `const Base64Base64 Base64 = "base64"`

          - `type URLImageSource struct{…}`

            - `Type URL`

              - `const URLURL URL = "url"`

            - `URL string`

        - `Type Image`

          - `const ImageImage Image = "image"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

      - `type DocumentBlockParamResp struct{…}`

        - `Source DocumentBlockParamSourceUnionResp`

          - `type Base64PDFSource struct{…}`

            - `Data string`

            - `MediaType ApplicationPDF`

              - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

            - `Type Base64`

              - `const Base64Base64 Base64 = "base64"`

          - `type PlainTextSource struct{…}`

            - `Data string`

            - `MediaType TextPlain`

              - `const TextPlainTextPlain TextPlain = "text/plain"`

            - `Type Text`

              - `const TextText Text = "text"`

          - `type ContentBlockSource struct{…}`

            - `Content ContentBlockSourceContentUnion`

              - `string`

              - `[]ContentBlockSourceContentItemUnion`

                - `type TextBlockParamResp struct{…}`

                - `type ImageBlockParamResp struct{…}`

            - `Type Content`

              - `const ContentContent Content = "content"`

          - `type URLPDFSource struct{…}`

            - `Type URL`

              - `const URLURL URL = "url"`

            - `URL string`

        - `Type Document`

          - `const DocumentDocument Document = "document"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Citations CitationsConfigParamResp`

          - `Enabled bool`

        - `Context string`

        - `Title string`

      - `type SearchResultBlockParamResp struct{…}`

        - `Content []TextBlockParamResp`

          - `Text string`

          - `Type Text`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations []TextCitationParamUnionResp`

        - `Source string`

        - `Title string`

        - `Type SearchResult`

          - `const SearchResultSearchResult SearchResult = "search_result"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Citations CitationsConfigParamResp`

      - `type ThinkingBlockParamResp struct{…}`

        - `Signature string`

        - `Thinking string`

        - `Type Thinking`

          - `const ThinkingThinking Thinking = "thinking"`

      - `type RedactedThinkingBlockParamResp struct{…}`

        - `Data string`

        - `Type RedactedThinking`

          - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

      - `type ToolUseBlockParamResp struct{…}`

        - `ID string`

        - `Input map[string, any]`

        - `Name string`

        - `Type ToolUse`

          - `const ToolUseToolUse ToolUse = "tool_use"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Caller ToolUseBlockParamCallerUnionResp`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

            - `Type Direct`

              - `const DirectDirect Direct = "direct"`

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

            - `ToolID string`

            - `Type CodeExecution20250825`

              - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

          - `type ServerToolCaller20260120 struct{…}`

            - `ToolID string`

            - `Type CodeExecution20260120`

              - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

      - `type ToolResultBlockParamResp struct{…}`

        - `ToolUseID string`

        - `Type ToolResult`

          - `const ToolResultToolResult ToolResult = "tool_result"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Content []ToolResultBlockParamContentUnionResp`

          - `[]ToolResultBlockParamContentUnionResp`

            - `type TextBlockParamResp struct{…}`

            - `type ImageBlockParamResp struct{…}`

            - `type SearchResultBlockParamResp struct{…}`

            - `type DocumentBlockParamResp struct{…}`

            - `type ToolReferenceBlockParamResp struct{…}`

              Tool reference block that can be included in tool_result content.

              - `ToolName string`

              - `Type ToolReference`

                - `const ToolReferenceToolReference ToolReference = "tool_reference"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

        - `IsError bool`

      - `type ServerToolUseBlockParamResp struct{…}`

        - `ID string`

        - `Input map[string, any]`

        - `Name ServerToolUseBlockParamName`

          - `const ServerToolUseBlockParamNameWebSearch ServerToolUseBlockParamName = "web_search"`

          - `const ServerToolUseBlockParamNameWebFetch ServerToolUseBlockParamName = "web_fetch"`

          - `const ServerToolUseBlockParamNameCodeExecution ServerToolUseBlockParamName = "code_execution"`

          - `const ServerToolUseBlockParamNameBashCodeExecution ServerToolUseBlockParamName = "bash_code_execution"`

          - `const ServerToolUseBlockParamNameTextEditorCodeExecution ServerToolUseBlockParamName = "text_editor_code_execution"`

          - `const ServerToolUseBlockParamNameToolSearchToolRegex ServerToolUseBlockParamName = "tool_search_tool_regex"`

          - `const ServerToolUseBlockParamNameToolSearchToolBm25 ServerToolUseBlockParamName = "tool_search_tool_bm25"`

        - `Type ServerToolUse`

          - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Caller ServerToolUseBlockParamCallerUnionResp`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

          - `type ServerToolCaller20260120 struct{…}`

      - `type WebSearchToolResultBlockParamResp struct{…}`

        - `Content WebSearchToolResultBlockParamContentUnionResp`

          - `[]WebSearchResultBlockParamResp`

            - `EncryptedContent string`

            - `Title string`

            - `Type WebSearchResult`

              - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

            - `URL string`

            - `PageAge string`

          - `type WebSearchToolRequestError struct{…}`

            - `ErrorCode WebSearchToolResultErrorCode`

              - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

              - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

              - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

              - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

              - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

              - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

            - `Type WebSearchToolResultError`

              - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

        - `ToolUseID string`

        - `Type WebSearchToolResult`

          - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Caller WebSearchToolResultBlockParamCallerUnionResp`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

          - `type ServerToolCaller20260120 struct{…}`

      - `type WebFetchToolResultBlockParamResp struct{…}`

        - `Content WebFetchToolResultBlockParamContentUnionResp`

          - `type WebFetchToolResultErrorBlockParamResp struct{…}`

            - `ErrorCode WebFetchToolResultErrorCode`

              - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

              - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

              - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

              - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

              - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

              - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

              - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

              - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

              - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

            - `Type WebFetchToolResultError`

              - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

          - `type WebFetchBlockParamResp struct{…}`

            - `Content DocumentBlockParamResp`

            - `Type WebFetchResult`

              - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

            - `URL string`

              Fetched content URL

            - `RetrievedAt string`

              ISO 8601 timestamp when the content was retrieved

        - `ToolUseID string`

        - `Type WebFetchToolResult`

          - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Caller WebFetchToolResultBlockParamCallerUnionResp`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

          - `type ServerToolCaller20260120 struct{…}`

      - `type CodeExecutionToolResultBlockParamResp struct{…}`

        - `Content CodeExecutionToolResultBlockParamContentUnionResp`

          Code execution result with encrypted stdout for PFC + web_search results.

          - `type CodeExecutionToolResultErrorParamResp struct{…}`

            - `ErrorCode CodeExecutionToolResultErrorCode`

              - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

              - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

              - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

              - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

            - `Type CodeExecutionToolResultError`

              - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

          - `type CodeExecutionResultBlockParamResp struct{…}`

            - `Content []CodeExecutionOutputBlockParamResp`

              - `FileID string`

              - `Type CodeExecutionOutput`

                - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

            - `ReturnCode int64`

            - `Stderr string`

            - `Stdout string`

            - `Type CodeExecutionResult`

              - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

          - `type EncryptedCodeExecutionResultBlockParamResp struct{…}`

            Code execution result with encrypted stdout for PFC + web_search results.

            - `Content []CodeExecutionOutputBlockParamResp`

              - `FileID string`

              - `Type CodeExecutionOutput`

            - `EncryptedStdout string`

            - `ReturnCode int64`

            - `Stderr string`

            - `Type EncryptedCodeExecutionResult`

              - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

        - `ToolUseID string`

        - `Type CodeExecutionToolResult`

          - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

      - `type BashCodeExecutionToolResultBlockParamResp struct{…}`

        - `Content BashCodeExecutionToolResultBlockParamContentUnionResp`

          - `type BashCodeExecutionToolResultErrorParamResp struct{…}`

            - `ErrorCode BashCodeExecutionToolResultErrorCode`

              - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

              - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

              - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

              - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

            - `Type BashCodeExecutionToolResultError`

              - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

          - `type BashCodeExecutionResultBlockParamResp struct{…}`

            - `Content []BashCodeExecutionOutputBlockParamResp`

              - `FileID string`

              - `Type BashCodeExecutionOutput`

                - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

            - `ReturnCode int64`

            - `Stderr string`

            - `Stdout string`

            - `Type BashCodeExecutionResult`

              - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

        - `ToolUseID string`

        - `Type BashCodeExecutionToolResult`

          - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

      - `type TextEditorCodeExecutionToolResultBlockParamResp struct{…}`

        - `Content TextEditorCodeExecutionToolResultBlockParamContentUnionResp`

          - `type TextEditorCodeExecutionToolResultErrorParamResp struct{…}`

            - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

              - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

              - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

              - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

              - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

            - `Type TextEditorCodeExecutionToolResultError`

              - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

            - `ErrorMessage string`

          - `type TextEditorCodeExecutionViewResultBlockParamResp struct{…}`

            - `Content string`

            - `FileType TextEditorCodeExecutionViewResultBlockParamFileType`

              - `const TextEditorCodeExecutionViewResultBlockParamFileTypeText TextEditorCodeExecutionViewResultBlockParamFileType = "text"`

              - `const TextEditorCodeExecutionViewResultBlockParamFileTypeImage TextEditorCodeExecutionViewResultBlockParamFileType = "image"`

              - `const TextEditorCodeExecutionViewResultBlockParamFileTypePDF TextEditorCodeExecutionViewResultBlockParamFileType = "pdf"`

            - `Type TextEditorCodeExecutionViewResult`

              - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

            - `NumLines int64`

            - `StartLine int64`

            - `TotalLines int64`

          - `type TextEditorCodeExecutionCreateResultBlockParamResp struct{…}`

            - `IsFileUpdate bool`

            - `Type TextEditorCodeExecutionCreateResult`

              - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

          - `type TextEditorCodeExecutionStrReplaceResultBlockParamResp struct{…}`

            - `Type TextEditorCodeExecutionStrReplaceResult`

              - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

            - `Lines []string`

            - `NewLines int64`

            - `NewStart int64`

            - `OldLines int64`

            - `OldStart int64`

        - `ToolUseID string`

        - `Type TextEditorCodeExecutionToolResult`

          - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

      - `type ToolSearchToolResultBlockParamResp struct{…}`

        - `Content ToolSearchToolResultBlockParamContentUnionResp`

          - `type ToolSearchToolResultErrorParamResp struct{…}`

            - `ErrorCode ToolSearchToolResultErrorCode`

              - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

              - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

              - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

              - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

            - `Type ToolSearchToolResultError`

              - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

            - `ErrorMessage string`

          - `type ToolSearchToolSearchResultBlockParamResp struct{…}`

            - `ToolReferences []ToolReferenceBlockParamResp`

              - `ToolName string`

              - `Type ToolReference`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

            - `Type ToolSearchToolSearchResult`

              - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

        - `ToolUseID string`

        - `Type ToolSearchToolResult`

          - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

      - `type ContainerUploadBlockParamResp struct{…}`

        A content block that represents a file to be uploaded to the container
        Files uploaded via this block will be available in the container's input directory.

        - `FileID string`

        - `Type ContainerUpload`

          - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

      - `type MidConversationSystemBlockParamResp struct{…}`

        System instructions that appear mid-conversation.

        Use this block to provide or update system-level instructions at a specific
        point in the conversation, rather than only via the top-level `system` parameter.

        - `Content []TextBlockParamResp`

          System instruction text blocks.

          - `Text string`

          - `Type Text`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations []TextCitationParamUnionResp`

        - `Type MidConvSystem`

          - `const MidConvSystemMidConvSystem MidConvSystem = "mid_conv_system"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

  - `Role MessageParamRole`

    - `const MessageParamRoleUser MessageParamRole = "user"`

    - `const MessageParamRoleAssistant MessageParamRole = "assistant"`

    - `const MessageParamRoleSystem MessageParamRole = "system"`

### Message Tokens Count

- `type MessageTokensCount struct{…}`

  - `InputTokens int64`

    The total number of tokens across the provided list of messages, system prompt, and tools.

### Metadata

- `type Metadata struct{…}`

  - `UserID string`

    An external identifier for the user who is associated with the request.

    This should be a uuid, hash value, or other opaque identifier. Anthropic may use this id to help detect abuse. Do not include any identifying information such as name, email address, or phone number.

### Mid Conversation System Block Param

- `type MidConversationSystemBlockParamResp struct{…}`

  System instructions that appear mid-conversation.

  Use this block to provide or update system-level instructions at a specific
  point in the conversation, rather than only via the top-level `system` parameter.

  - `Content []TextBlockParamResp`

    System instruction text blocks.

    - `Text string`

    - `Type Text`

      - `const TextText Text = "text"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

      - `Type Ephemeral`

        - `const EphemeralEphemeral Ephemeral = "ephemeral"`

      - `TTL CacheControlEphemeralTTL`

        The time-to-live for the cache control breakpoint.

        This may be one the following values:

        - `5m`: 5 minutes
        - `1h`: 1 hour

        Defaults to `5m`.

        - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

        - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

    - `Citations []TextCitationParamUnionResp`

      - `type CitationCharLocationParamResp struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndCharIndex int64`

        - `StartCharIndex int64`

        - `Type CharLocation`

          - `const CharLocationCharLocation CharLocation = "char_location"`

      - `type CitationPageLocationParamResp struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndPageNumber int64`

        - `StartPageNumber int64`

        - `Type PageLocation`

          - `const PageLocationPageLocation PageLocation = "page_location"`

      - `type CitationContentBlockLocationParamResp struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Type ContentBlockLocation`

          - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

      - `type CitationWebSearchResultLocationParamResp struct{…}`

        - `CitedText string`

        - `EncryptedIndex string`

        - `Title string`

        - `Type WebSearchResultLocation`

          - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

        - `URL string`

      - `type CitationSearchResultLocationParamResp struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `SearchResultIndex int64`

          0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

          Counted separately from `document_index`; server-side web search results are not included in this count.

        - `Source string`

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Title string`

        - `Type SearchResultLocation`

          - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

  - `Type MidConvSystem`

    - `const MidConvSystemMidConvSystem MidConvSystem = "mid_conv_system"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

### Model

- `type Model interface{…}`

  The model that will complete your prompt.

  See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

  - `type Model string`

    The model that will complete your prompt.

    See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

    - `const ModelClaudeFable5 Model = "claude-fable-5"`

      Next generation of intelligence for the hardest knowledge work and coding problems

    - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

      Most capable model for cybersecurity and biology research

    - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

      Frontier intelligence for long-running agents and coding

    - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

      Frontier intelligence for long-running agents and coding

    - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

      New class of intelligence, strongest in coding and cybersecurity

    - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

      Frontier intelligence for long-running agents and coding

    - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

      Best combination of speed and intelligence

    - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

      Fastest model with near-frontier intelligence

    - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

      Fastest model with near-frontier intelligence

    - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

      Premium model combining maximum intelligence with practical performance

    - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

      Premium model combining maximum intelligence with practical performance

    - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

      High-performance model for agents and coding

    - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

      High-performance model for agents and coding

    - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

      Exceptional model for specialized complex tasks

    - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

      Exceptional model for specialized complex tasks

    - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

      Powerful model for complex tasks

    - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

      Powerful model for complex tasks

    - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

      High-performance model with extended thinking

    - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

      High-performance model with extended thinking

    - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

      Fast and cost-effective model

  - `string`

### Output Config

- `type OutputConfig struct{…}`

  - `Effort OutputConfigEffort`

    All possible effort levels.

    - `const OutputConfigEffortLow OutputConfigEffort = "low"`

    - `const OutputConfigEffortMedium OutputConfigEffort = "medium"`

    - `const OutputConfigEffortHigh OutputConfigEffort = "high"`

    - `const OutputConfigEffortXhigh OutputConfigEffort = "xhigh"`

    - `const OutputConfigEffortMax OutputConfigEffort = "max"`

  - `Format JSONOutputFormat`

    A schema to specify Claude's output format in responses. See [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs)

    - `Schema map[string, any]`

      The JSON schema of the format

    - `Type JSONSchema`

      - `const JSONSchemaJSONSchema JSONSchema = "json_schema"`

### Output Tokens Details

- `type OutputTokensDetails struct{…}`

  - `ThinkingTokens int64`

    Number of output tokens the model generated as internal reasoning, including
    the thinking-block delimiter tokens.

    Reflects the raw reasoning the model produced, not the (possibly shorter)
    summarized thinking text returned in the response body. Computed by
    re-tokenizing the raw reasoning text, so it may differ from the model's exact
    generation count by a small number of tokens. Always ≤ `output_tokens`;
    `output_tokens - thinking_tokens` approximates the non-reasoning output.

### Plain Text Source

- `type PlainTextSource struct{…}`

  - `Data string`

  - `MediaType TextPlain`

    - `const TextPlainTextPlain TextPlain = "text/plain"`

  - `Type Text`

    - `const TextText Text = "text"`

### Raw Content Block Delta

- `type RawContentBlockDeltaUnion interface{…}`

  - `type TextDelta struct{…}`

    - `Text string`

    - `Type TextDelta`

      - `const TextDeltaTextDelta TextDelta = "text_delta"`

  - `type InputJSONDelta struct{…}`

    - `PartialJSON string`

    - `Type InputJSONDelta`

      - `const InputJSONDeltaInputJSONDelta InputJSONDelta = "input_json_delta"`

  - `type CitationsDelta struct{…}`

    - `Citation CitationsDeltaCitationUnion`

      - `type CitationCharLocation struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndCharIndex int64`

        - `FileID string`

        - `StartCharIndex int64`

        - `Type CharLocation`

          - `const CharLocationCharLocation CharLocation = "char_location"`

      - `type CitationPageLocation struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndPageNumber int64`

        - `FileID string`

        - `StartPageNumber int64`

        - `Type PageLocation`

          - `const PageLocationPageLocation PageLocation = "page_location"`

      - `type CitationContentBlockLocation struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `FileID string`

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Type ContentBlockLocation`

          - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

      - `type CitationsWebSearchResultLocation struct{…}`

        - `CitedText string`

        - `EncryptedIndex string`

        - `Title string`

        - `Type WebSearchResultLocation`

          - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

        - `URL string`

      - `type CitationsSearchResultLocation struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `SearchResultIndex int64`

          0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

          Counted separately from `document_index`; server-side web search results are not included in this count.

        - `Source string`

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Title string`

        - `Type SearchResultLocation`

          - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

    - `Type CitationsDelta`

      - `const CitationsDeltaCitationsDelta CitationsDelta = "citations_delta"`

  - `type ThinkingDelta struct{…}`

    - `Thinking string`

    - `Type ThinkingDelta`

      - `const ThinkingDeltaThinkingDelta ThinkingDelta = "thinking_delta"`

  - `type SignatureDelta struct{…}`

    - `Signature string`

    - `Type SignatureDelta`

      - `const SignatureDeltaSignatureDelta SignatureDelta = "signature_delta"`

### Raw Content Block Delta Event

- `type ContentBlockDeltaEvent struct{…}`

  - `Delta RawContentBlockDeltaUnion`

    - `type TextDelta struct{…}`

      - `Text string`

      - `Type TextDelta`

        - `const TextDeltaTextDelta TextDelta = "text_delta"`

    - `type InputJSONDelta struct{…}`

      - `PartialJSON string`

      - `Type InputJSONDelta`

        - `const InputJSONDeltaInputJSONDelta InputJSONDelta = "input_json_delta"`

    - `type CitationsDelta struct{…}`

      - `Citation CitationsDeltaCitationUnion`

        - `type CitationCharLocation struct{…}`

          - `CitedText string`

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndCharIndex int64`

          - `FileID string`

          - `StartCharIndex int64`

          - `Type CharLocation`

            - `const CharLocationCharLocation CharLocation = "char_location"`

        - `type CitationPageLocation struct{…}`

          - `CitedText string`

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndPageNumber int64`

          - `FileID string`

          - `StartPageNumber int64`

          - `Type PageLocation`

            - `const PageLocationPageLocation PageLocation = "page_location"`

        - `type CitationContentBlockLocation struct{…}`

          - `CitedText string`

            The full text of the cited block range, concatenated.

            Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndBlockIndex int64`

            Exclusive 0-based end index of the cited block range in the source's `content` array.

            Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

          - `FileID string`

          - `StartBlockIndex int64`

            0-based index of the first cited block in the source's `content` array.

          - `Type ContentBlockLocation`

            - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

        - `type CitationsWebSearchResultLocation struct{…}`

          - `CitedText string`

          - `EncryptedIndex string`

          - `Title string`

          - `Type WebSearchResultLocation`

            - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

          - `URL string`

        - `type CitationsSearchResultLocation struct{…}`

          - `CitedText string`

            The full text of the cited block range, concatenated.

            Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

          - `EndBlockIndex int64`

            Exclusive 0-based end index of the cited block range in the source's `content` array.

            Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

          - `SearchResultIndex int64`

            0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

            Counted separately from `document_index`; server-side web search results are not included in this count.

          - `Source string`

          - `StartBlockIndex int64`

            0-based index of the first cited block in the source's `content` array.

          - `Title string`

          - `Type SearchResultLocation`

            - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

      - `Type CitationsDelta`

        - `const CitationsDeltaCitationsDelta CitationsDelta = "citations_delta"`

    - `type ThinkingDelta struct{…}`

      - `Thinking string`

      - `Type ThinkingDelta`

        - `const ThinkingDeltaThinkingDelta ThinkingDelta = "thinking_delta"`

    - `type SignatureDelta struct{…}`

      - `Signature string`

      - `Type SignatureDelta`

        - `const SignatureDeltaSignatureDelta SignatureDelta = "signature_delta"`

  - `Index int64`

  - `Type ContentBlockDelta`

    - `const ContentBlockDeltaContentBlockDelta ContentBlockDelta = "content_block_delta"`

### Raw Content Block Start Event

- `type ContentBlockStartEvent struct{…}`

  - `ContentBlock ContentBlockStartEventContentBlockUnion`

    Response model for a file uploaded to the container.

    - `type TextBlock struct{…}`

      - `Citations []TextCitationUnion`

        Citations supporting the text block.

        The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

        - `type CitationCharLocation struct{…}`

          - `CitedText string`

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndCharIndex int64`

          - `FileID string`

          - `StartCharIndex int64`

          - `Type CharLocation`

            - `const CharLocationCharLocation CharLocation = "char_location"`

        - `type CitationPageLocation struct{…}`

          - `CitedText string`

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndPageNumber int64`

          - `FileID string`

          - `StartPageNumber int64`

          - `Type PageLocation`

            - `const PageLocationPageLocation PageLocation = "page_location"`

        - `type CitationContentBlockLocation struct{…}`

          - `CitedText string`

            The full text of the cited block range, concatenated.

            Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

          - `DocumentIndex int64`

          - `DocumentTitle string`

          - `EndBlockIndex int64`

            Exclusive 0-based end index of the cited block range in the source's `content` array.

            Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

          - `FileID string`

          - `StartBlockIndex int64`

            0-based index of the first cited block in the source's `content` array.

          - `Type ContentBlockLocation`

            - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

        - `type CitationsWebSearchResultLocation struct{…}`

          - `CitedText string`

          - `EncryptedIndex string`

          - `Title string`

          - `Type WebSearchResultLocation`

            - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

          - `URL string`

        - `type CitationsSearchResultLocation struct{…}`

          - `CitedText string`

            The full text of the cited block range, concatenated.

            Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

          - `EndBlockIndex int64`

            Exclusive 0-based end index of the cited block range in the source's `content` array.

            Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

          - `SearchResultIndex int64`

            0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

            Counted separately from `document_index`; server-side web search results are not included in this count.

          - `Source string`

          - `StartBlockIndex int64`

            0-based index of the first cited block in the source's `content` array.

          - `Title string`

          - `Type SearchResultLocation`

            - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

      - `Text string`

      - `Type Text`

        - `const TextText Text = "text"`

    - `type ThinkingBlock struct{…}`

      - `Signature string`

      - `Thinking string`

      - `Type Thinking`

        - `const ThinkingThinking Thinking = "thinking"`

    - `type RedactedThinkingBlock struct{…}`

      - `Data string`

      - `Type RedactedThinking`

        - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

    - `type ToolUseBlock struct{…}`

      - `ID string`

      - `Caller ToolUseBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

          - `Type Direct`

            - `const DirectDirect Direct = "direct"`

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

          - `ToolID string`

          - `Type CodeExecution20250825`

            - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

        - `type ServerToolCaller20260120 struct{…}`

          - `ToolID string`

          - `Type CodeExecution20260120`

            - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

      - `Input map[string, any]`

      - `Name string`

      - `Type ToolUse`

        - `const ToolUseToolUse ToolUse = "tool_use"`

    - `type ServerToolUseBlock struct{…}`

      - `ID string`

      - `Caller ServerToolUseBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

        - `type ServerToolCaller20260120 struct{…}`

      - `Input map[string, any]`

      - `Name ServerToolUseBlockName`

        - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

        - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

        - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

        - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

        - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

        - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

        - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

      - `Type ServerToolUse`

        - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

    - `type WebSearchToolResultBlock struct{…}`

      - `Caller WebSearchToolResultBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

        - `type ServerToolCaller20260120 struct{…}`

      - `Content WebSearchToolResultBlockContentUnion`

        - `type WebSearchToolResultError struct{…}`

          - `ErrorCode WebSearchToolResultErrorCode`

            - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

            - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

            - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

            - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

            - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

            - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

          - `Type WebSearchToolResultError`

            - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

        - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

          - `EncryptedContent string`

          - `PageAge string`

          - `Title string`

          - `Type WebSearchResult`

            - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

          - `URL string`

      - `ToolUseID string`

      - `Type WebSearchToolResult`

        - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

    - `type WebFetchToolResultBlock struct{…}`

      - `Caller WebFetchToolResultBlockCallerUnion`

        Tool invocation directly from the model.

        - `type DirectCaller struct{…}`

          Tool invocation directly from the model.

        - `type ServerToolCaller struct{…}`

          Tool invocation generated by a server-side tool.

        - `type ServerToolCaller20260120 struct{…}`

      - `Content WebFetchToolResultBlockContentUnion`

        - `type WebFetchToolResultErrorBlock struct{…}`

          - `ErrorCode WebFetchToolResultErrorCode`

            - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

            - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

            - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

            - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

            - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

            - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

            - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

            - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

            - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

          - `Type WebFetchToolResultError`

            - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

        - `type WebFetchBlock struct{…}`

          - `Content DocumentBlock`

            - `Citations CitationsConfig`

              Citation configuration for the document

              - `Enabled bool`

            - `Source DocumentBlockSourceUnion`

              - `type Base64PDFSource struct{…}`

                - `Data string`

                - `MediaType ApplicationPDF`

                  - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                - `Type Base64`

                  - `const Base64Base64 Base64 = "base64"`

              - `type PlainTextSource struct{…}`

                - `Data string`

                - `MediaType TextPlain`

                  - `const TextPlainTextPlain TextPlain = "text/plain"`

                - `Type Text`

                  - `const TextText Text = "text"`

            - `Title string`

              The title of the document

            - `Type Document`

              - `const DocumentDocument Document = "document"`

          - `RetrievedAt string`

            ISO 8601 timestamp when the content was retrieved

          - `Type WebFetchResult`

            - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

          - `URL string`

            Fetched content URL

      - `ToolUseID string`

      - `Type WebFetchToolResult`

        - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

    - `type CodeExecutionToolResultBlock struct{…}`

      - `Content CodeExecutionToolResultBlockContentUnion`

        Code execution result with encrypted stdout for PFC + web_search results.

        - `type CodeExecutionToolResultError struct{…}`

          - `ErrorCode CodeExecutionToolResultErrorCode`

            - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

            - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

            - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

            - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

          - `Type CodeExecutionToolResultError`

            - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

        - `type CodeExecutionResultBlock struct{…}`

          - `Content []CodeExecutionOutputBlock`

            - `FileID string`

            - `Type CodeExecutionOutput`

              - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

          - `ReturnCode int64`

          - `Stderr string`

          - `Stdout string`

          - `Type CodeExecutionResult`

            - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

        - `type EncryptedCodeExecutionResultBlock struct{…}`

          Code execution result with encrypted stdout for PFC + web_search results.

          - `Content []CodeExecutionOutputBlock`

            - `FileID string`

            - `Type CodeExecutionOutput`

          - `EncryptedStdout string`

          - `ReturnCode int64`

          - `Stderr string`

          - `Type EncryptedCodeExecutionResult`

            - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

      - `ToolUseID string`

      - `Type CodeExecutionToolResult`

        - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

    - `type BashCodeExecutionToolResultBlock struct{…}`

      - `Content BashCodeExecutionToolResultBlockContentUnion`

        - `type BashCodeExecutionToolResultError struct{…}`

          - `ErrorCode BashCodeExecutionToolResultErrorCode`

            - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

            - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

            - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

            - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

            - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

          - `Type BashCodeExecutionToolResultError`

            - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

        - `type BashCodeExecutionResultBlock struct{…}`

          - `Content []BashCodeExecutionOutputBlock`

            - `FileID string`

            - `Type BashCodeExecutionOutput`

              - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

          - `ReturnCode int64`

          - `Stderr string`

          - `Stdout string`

          - `Type BashCodeExecutionResult`

            - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

      - `ToolUseID string`

      - `Type BashCodeExecutionToolResult`

        - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

    - `type TextEditorCodeExecutionToolResultBlock struct{…}`

      - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

        - `type TextEditorCodeExecutionToolResultError struct{…}`

          - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

            - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

            - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

            - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

            - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

            - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

          - `ErrorMessage string`

          - `Type TextEditorCodeExecutionToolResultError`

            - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

        - `type TextEditorCodeExecutionViewResultBlock struct{…}`

          - `Content string`

          - `FileType TextEditorCodeExecutionViewResultBlockFileType`

            - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

            - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

            - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

          - `NumLines int64`

          - `StartLine int64`

          - `TotalLines int64`

          - `Type TextEditorCodeExecutionViewResult`

            - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

        - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

          - `IsFileUpdate bool`

          - `Type TextEditorCodeExecutionCreateResult`

            - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

        - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

          - `Lines []string`

          - `NewLines int64`

          - `NewStart int64`

          - `OldLines int64`

          - `OldStart int64`

          - `Type TextEditorCodeExecutionStrReplaceResult`

            - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

      - `ToolUseID string`

      - `Type TextEditorCodeExecutionToolResult`

        - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

    - `type ToolSearchToolResultBlock struct{…}`

      - `Content ToolSearchToolResultBlockContentUnion`

        - `type ToolSearchToolResultError struct{…}`

          - `ErrorCode ToolSearchToolResultErrorCode`

            - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

            - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

            - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

            - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

          - `ErrorMessage string`

          - `Type ToolSearchToolResultError`

            - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

        - `type ToolSearchToolSearchResultBlock struct{…}`

          - `ToolReferences []ToolReferenceBlock`

            - `ToolName string`

            - `Type ToolReference`

              - `const ToolReferenceToolReference ToolReference = "tool_reference"`

          - `Type ToolSearchToolSearchResult`

            - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

      - `ToolUseID string`

      - `Type ToolSearchToolResult`

        - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

    - `type ContainerUploadBlock struct{…}`

      Response model for a file uploaded to the container.

      - `FileID string`

      - `Type ContainerUpload`

        - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

  - `Index int64`

  - `Type ContentBlockStart`

    - `const ContentBlockStartContentBlockStart ContentBlockStart = "content_block_start"`

### Raw Content Block Stop Event

- `type ContentBlockStopEvent struct{…}`

  - `Index int64`

  - `Type ContentBlockStop`

    - `const ContentBlockStopContentBlockStop ContentBlockStop = "content_block_stop"`

### Raw Message Delta Event

- `type MessageDeltaEvent struct{…}`

  - `Delta MessageDeltaEventDelta`

    - `Container Container`

      Information about the container used in the request (for the code execution tool)

      - `ID string`

        Identifier for the container used in this request

      - `ExpiresAt Time`

        The time at which the container will expire.

    - `StopDetails RefusalStopDetails`

      Structured information about a refusal.

      - `Category RefusalStopDetailsCategory`

        The policy category that triggered the refusal.

        `null` when the refusal doesn't map to a named category.

        - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

        - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

        - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

      - `Explanation string`

        Human-readable explanation of the refusal.

        This text is not guaranteed to be stable. `null` when no explanation is available for the category.

      - `Type Refusal`

        - `const RefusalRefusal Refusal = "refusal"`

    - `StopReason StopReason`

      - `const StopReasonEndTurn StopReason = "end_turn"`

      - `const StopReasonMaxTokens StopReason = "max_tokens"`

      - `const StopReasonStopSequence StopReason = "stop_sequence"`

      - `const StopReasonToolUse StopReason = "tool_use"`

      - `const StopReasonPauseTurn StopReason = "pause_turn"`

      - `const StopReasonRefusal StopReason = "refusal"`

    - `StopSequence string`

  - `Type MessageDelta`

    - `const MessageDeltaMessageDelta MessageDelta = "message_delta"`

  - `Usage MessageDeltaUsage`

    Billing and rate-limit usage.

    Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

    Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

    For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

    Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

    - `CacheCreationInputTokens int64`

      The cumulative number of input tokens used to create the cache entry.

    - `CacheReadInputTokens int64`

      The cumulative number of input tokens read from the cache.

    - `InputTokens int64`

      The cumulative number of input tokens which were used.

    - `OutputTokens int64`

      The cumulative number of output tokens which were used.

    - `OutputTokensDetails OutputTokensDetails`

      Breakdown of output tokens by category.

      `output_tokens` remains the inclusive, authoritative total used for billing.
      This object provides a read-only decomposition for observability — for example,
      how many of the billed output tokens were spent on internal reasoning that may
      have been summarized before being returned to you.

      - `ThinkingTokens int64`

        Number of output tokens the model generated as internal reasoning, including
        the thinking-block delimiter tokens.

        Reflects the raw reasoning the model produced, not the (possibly shorter)
        summarized thinking text returned in the response body. Computed by
        re-tokenizing the raw reasoning text, so it may differ from the model's exact
        generation count by a small number of tokens. Always ≤ `output_tokens`;
        `output_tokens - thinking_tokens` approximates the non-reasoning output.

    - `ServerToolUse ServerToolUsage`

      The number of server tool requests.

      - `WebFetchRequests int64`

        The number of web fetch tool requests.

      - `WebSearchRequests int64`

        The number of web search tool requests.

### Raw Message Start Event

- `type MessageStartEvent struct{…}`

  - `Message Message`

    - `ID string`

      Unique object identifier.

      The format and length of IDs may change over time.

    - `Container Container`

      Information about the container used in the request (for the code execution tool)

      - `ID string`

        Identifier for the container used in this request

      - `ExpiresAt Time`

        The time at which the container will expire.

    - `Content []ContentBlockUnion`

      Content generated by the model.

      This is an array of content blocks, each of which has a `type` that determines its shape.

      Example:

      ```json
      [{"type": "text", "text": "Hi, I'm Claude."}]
      ```

      If the request input `messages` ended with an `assistant` turn, then the response `content` will continue directly from that last turn. You can use this to constrain the model's output.

      For example, if the input `messages` were:

      ```json
      [
        {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
        {"role": "assistant", "content": "The best answer is ("}
      ]
      ```

      Then the response `content` might be:

      ```json
      [{"type": "text", "text": "B)"}]
      ```

      - `type TextBlock struct{…}`

        - `Citations []TextCitationUnion`

          Citations supporting the text block.

          The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

          - `type CitationCharLocation struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndCharIndex int64`

            - `FileID string`

            - `StartCharIndex int64`

            - `Type CharLocation`

              - `const CharLocationCharLocation CharLocation = "char_location"`

          - `type CitationPageLocation struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndPageNumber int64`

            - `FileID string`

            - `StartPageNumber int64`

            - `Type PageLocation`

              - `const PageLocationPageLocation PageLocation = "page_location"`

          - `type CitationContentBlockLocation struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `FileID string`

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Type ContentBlockLocation`

              - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

          - `type CitationsWebSearchResultLocation struct{…}`

            - `CitedText string`

            - `EncryptedIndex string`

            - `Title string`

            - `Type WebSearchResultLocation`

              - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

            - `URL string`

          - `type CitationsSearchResultLocation struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `SearchResultIndex int64`

              0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

              Counted separately from `document_index`; server-side web search results are not included in this count.

            - `Source string`

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Title string`

            - `Type SearchResultLocation`

              - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

        - `Text string`

        - `Type Text`

          - `const TextText Text = "text"`

      - `type ThinkingBlock struct{…}`

        - `Signature string`

        - `Thinking string`

        - `Type Thinking`

          - `const ThinkingThinking Thinking = "thinking"`

      - `type RedactedThinkingBlock struct{…}`

        - `Data string`

        - `Type RedactedThinking`

          - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

      - `type ToolUseBlock struct{…}`

        - `ID string`

        - `Caller ToolUseBlockCallerUnion`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

            - `Type Direct`

              - `const DirectDirect Direct = "direct"`

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

            - `ToolID string`

            - `Type CodeExecution20250825`

              - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

          - `type ServerToolCaller20260120 struct{…}`

            - `ToolID string`

            - `Type CodeExecution20260120`

              - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

        - `Input map[string, any]`

        - `Name string`

        - `Type ToolUse`

          - `const ToolUseToolUse ToolUse = "tool_use"`

      - `type ServerToolUseBlock struct{…}`

        - `ID string`

        - `Caller ServerToolUseBlockCallerUnion`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

          - `type ServerToolCaller20260120 struct{…}`

        - `Input map[string, any]`

        - `Name ServerToolUseBlockName`

          - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

          - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

          - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

          - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

          - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

          - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

          - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

        - `Type ServerToolUse`

          - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

      - `type WebSearchToolResultBlock struct{…}`

        - `Caller WebSearchToolResultBlockCallerUnion`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

          - `type ServerToolCaller20260120 struct{…}`

        - `Content WebSearchToolResultBlockContentUnion`

          - `type WebSearchToolResultError struct{…}`

            - `ErrorCode WebSearchToolResultErrorCode`

              - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

              - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

              - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

              - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

              - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

              - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

            - `Type WebSearchToolResultError`

              - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

          - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

            - `EncryptedContent string`

            - `PageAge string`

            - `Title string`

            - `Type WebSearchResult`

              - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

            - `URL string`

        - `ToolUseID string`

        - `Type WebSearchToolResult`

          - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

      - `type WebFetchToolResultBlock struct{…}`

        - `Caller WebFetchToolResultBlockCallerUnion`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

          - `type ServerToolCaller20260120 struct{…}`

        - `Content WebFetchToolResultBlockContentUnion`

          - `type WebFetchToolResultErrorBlock struct{…}`

            - `ErrorCode WebFetchToolResultErrorCode`

              - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

              - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

              - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

              - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

              - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

              - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

              - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

              - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

              - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

            - `Type WebFetchToolResultError`

              - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

          - `type WebFetchBlock struct{…}`

            - `Content DocumentBlock`

              - `Citations CitationsConfig`

                Citation configuration for the document

                - `Enabled bool`

              - `Source DocumentBlockSourceUnion`

                - `type Base64PDFSource struct{…}`

                  - `Data string`

                  - `MediaType ApplicationPDF`

                    - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                  - `Type Base64`

                    - `const Base64Base64 Base64 = "base64"`

                - `type PlainTextSource struct{…}`

                  - `Data string`

                  - `MediaType TextPlain`

                    - `const TextPlainTextPlain TextPlain = "text/plain"`

                  - `Type Text`

                    - `const TextText Text = "text"`

              - `Title string`

                The title of the document

              - `Type Document`

                - `const DocumentDocument Document = "document"`

            - `RetrievedAt string`

              ISO 8601 timestamp when the content was retrieved

            - `Type WebFetchResult`

              - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

            - `URL string`

              Fetched content URL

        - `ToolUseID string`

        - `Type WebFetchToolResult`

          - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

      - `type CodeExecutionToolResultBlock struct{…}`

        - `Content CodeExecutionToolResultBlockContentUnion`

          Code execution result with encrypted stdout for PFC + web_search results.

          - `type CodeExecutionToolResultError struct{…}`

            - `ErrorCode CodeExecutionToolResultErrorCode`

              - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

              - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

              - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

              - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

            - `Type CodeExecutionToolResultError`

              - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

          - `type CodeExecutionResultBlock struct{…}`

            - `Content []CodeExecutionOutputBlock`

              - `FileID string`

              - `Type CodeExecutionOutput`

                - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

            - `ReturnCode int64`

            - `Stderr string`

            - `Stdout string`

            - `Type CodeExecutionResult`

              - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

          - `type EncryptedCodeExecutionResultBlock struct{…}`

            Code execution result with encrypted stdout for PFC + web_search results.

            - `Content []CodeExecutionOutputBlock`

              - `FileID string`

              - `Type CodeExecutionOutput`

            - `EncryptedStdout string`

            - `ReturnCode int64`

            - `Stderr string`

            - `Type EncryptedCodeExecutionResult`

              - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

        - `ToolUseID string`

        - `Type CodeExecutionToolResult`

          - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

      - `type BashCodeExecutionToolResultBlock struct{…}`

        - `Content BashCodeExecutionToolResultBlockContentUnion`

          - `type BashCodeExecutionToolResultError struct{…}`

            - `ErrorCode BashCodeExecutionToolResultErrorCode`

              - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

              - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

              - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

              - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

            - `Type BashCodeExecutionToolResultError`

              - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

          - `type BashCodeExecutionResultBlock struct{…}`

            - `Content []BashCodeExecutionOutputBlock`

              - `FileID string`

              - `Type BashCodeExecutionOutput`

                - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

            - `ReturnCode int64`

            - `Stderr string`

            - `Stdout string`

            - `Type BashCodeExecutionResult`

              - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

        - `ToolUseID string`

        - `Type BashCodeExecutionToolResult`

          - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

      - `type TextEditorCodeExecutionToolResultBlock struct{…}`

        - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

          - `type TextEditorCodeExecutionToolResultError struct{…}`

            - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

              - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

              - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

              - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

              - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

            - `ErrorMessage string`

            - `Type TextEditorCodeExecutionToolResultError`

              - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

          - `type TextEditorCodeExecutionViewResultBlock struct{…}`

            - `Content string`

            - `FileType TextEditorCodeExecutionViewResultBlockFileType`

              - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

              - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

              - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

            - `NumLines int64`

            - `StartLine int64`

            - `TotalLines int64`

            - `Type TextEditorCodeExecutionViewResult`

              - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

          - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

            - `IsFileUpdate bool`

            - `Type TextEditorCodeExecutionCreateResult`

              - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

          - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

            - `Lines []string`

            - `NewLines int64`

            - `NewStart int64`

            - `OldLines int64`

            - `OldStart int64`

            - `Type TextEditorCodeExecutionStrReplaceResult`

              - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

        - `ToolUseID string`

        - `Type TextEditorCodeExecutionToolResult`

          - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

      - `type ToolSearchToolResultBlock struct{…}`

        - `Content ToolSearchToolResultBlockContentUnion`

          - `type ToolSearchToolResultError struct{…}`

            - `ErrorCode ToolSearchToolResultErrorCode`

              - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

              - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

              - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

              - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

            - `ErrorMessage string`

            - `Type ToolSearchToolResultError`

              - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

          - `type ToolSearchToolSearchResultBlock struct{…}`

            - `ToolReferences []ToolReferenceBlock`

              - `ToolName string`

              - `Type ToolReference`

                - `const ToolReferenceToolReference ToolReference = "tool_reference"`

            - `Type ToolSearchToolSearchResult`

              - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

        - `ToolUseID string`

        - `Type ToolSearchToolResult`

          - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

      - `type ContainerUploadBlock struct{…}`

        Response model for a file uploaded to the container.

        - `FileID string`

        - `Type ContainerUpload`

          - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

    - `Model Model`

      The model that will complete your prompt.

      See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

      - `type Model string`

        The model that will complete your prompt.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `const ModelClaudeFable5 Model = "claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

          Most capable model for cybersecurity and biology research

        - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

          New class of intelligence, strongest in coding and cybersecurity

        - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

          Frontier intelligence for long-running agents and coding

        - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

        - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

          Exceptional model for specialized complex tasks

        - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

          Exceptional model for specialized complex tasks

        - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

          Powerful model for complex tasks

        - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

          Powerful model for complex tasks

        - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

          High-performance model with extended thinking

        - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

          High-performance model with extended thinking

        - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

          Fast and cost-effective model

      - `string`

    - `Role Assistant`

      Conversational role of the generated message.

      This will always be `"assistant"`.

      - `const AssistantAssistant Assistant = "assistant"`

    - `StopDetails RefusalStopDetails`

      Structured information about a refusal.

      - `Category RefusalStopDetailsCategory`

        The policy category that triggered the refusal.

        `null` when the refusal doesn't map to a named category.

        - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

        - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

        - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

      - `Explanation string`

        Human-readable explanation of the refusal.

        This text is not guaranteed to be stable. `null` when no explanation is available for the category.

      - `Type Refusal`

        - `const RefusalRefusal Refusal = "refusal"`

    - `StopReason StopReason`

      The reason that we stopped.

      This may be one the following values:

      * `"end_turn"`: the model reached a natural stopping point
      * `"max_tokens"`: we exceeded the requested `max_tokens` or the model's maximum
      * `"stop_sequence"`: one of your provided custom `stop_sequences` was generated
      * `"tool_use"`: the model invoked one or more tools
      * `"pause_turn"`: we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
      * `"refusal"`: when streaming classifiers intervene to handle potential policy violations

      In non-streaming mode this value is always non-null. In streaming mode, it is null in the `message_start` event and non-null otherwise.

      - `const StopReasonEndTurn StopReason = "end_turn"`

      - `const StopReasonMaxTokens StopReason = "max_tokens"`

      - `const StopReasonStopSequence StopReason = "stop_sequence"`

      - `const StopReasonToolUse StopReason = "tool_use"`

      - `const StopReasonPauseTurn StopReason = "pause_turn"`

      - `const StopReasonRefusal StopReason = "refusal"`

    - `StopSequence string`

      Which custom stop sequence was generated, if any.

      This value will be a non-null string if one of your custom stop sequences was generated.

    - `Type Message`

      Object type.

      For Messages, this is always `"message"`.

      - `const MessageMessage Message = "message"`

    - `Usage Usage`

      Billing and rate-limit usage.

      Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

      Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

      For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

      Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

      - `CacheCreation CacheCreation`

        Breakdown of cached tokens by TTL

        - `Ephemeral1hInputTokens int64`

          The number of input tokens used to create the 1 hour cache entry.

        - `Ephemeral5mInputTokens int64`

          The number of input tokens used to create the 5 minute cache entry.

      - `CacheCreationInputTokens int64`

        The number of input tokens used to create the cache entry.

      - `CacheReadInputTokens int64`

        The number of input tokens read from the cache.

      - `InferenceGeo string`

        The geographic region where inference was performed for this request.

      - `InputTokens int64`

        The number of input tokens which were used.

      - `OutputTokens int64`

        The number of output tokens which were used.

      - `OutputTokensDetails OutputTokensDetails`

        Breakdown of output tokens by category.

        `output_tokens` remains the inclusive, authoritative total used for billing.
        This object provides a read-only decomposition for observability — for example,
        how many of the billed output tokens were spent on internal reasoning that may
        have been summarized before being returned to you.

        - `ThinkingTokens int64`

          Number of output tokens the model generated as internal reasoning, including
          the thinking-block delimiter tokens.

          Reflects the raw reasoning the model produced, not the (possibly shorter)
          summarized thinking text returned in the response body. Computed by
          re-tokenizing the raw reasoning text, so it may differ from the model's exact
          generation count by a small number of tokens. Always ≤ `output_tokens`;
          `output_tokens - thinking_tokens` approximates the non-reasoning output.

      - `ServerToolUse ServerToolUsage`

        The number of server tool requests.

        - `WebFetchRequests int64`

          The number of web fetch tool requests.

        - `WebSearchRequests int64`

          The number of web search tool requests.

      - `ServiceTier UsageServiceTier`

        If the request used the priority, standard, or batch tier.

        - `const UsageServiceTierStandard UsageServiceTier = "standard"`

        - `const UsageServiceTierPriority UsageServiceTier = "priority"`

        - `const UsageServiceTierBatch UsageServiceTier = "batch"`

  - `Type MessageStart`

    - `const MessageStartMessageStart MessageStart = "message_start"`

### Raw Message Stop Event

- `type MessageStopEvent struct{…}`

  - `Type MessageStop`

    - `const MessageStopMessageStop MessageStop = "message_stop"`

### Raw Message Stream Event

- `type MessageStreamEventUnion interface{…}`

  - `type MessageStartEvent struct{…}`

    - `Message Message`

      - `ID string`

        Unique object identifier.

        The format and length of IDs may change over time.

      - `Container Container`

        Information about the container used in the request (for the code execution tool)

        - `ID string`

          Identifier for the container used in this request

        - `ExpiresAt Time`

          The time at which the container will expire.

      - `Content []ContentBlockUnion`

        Content generated by the model.

        This is an array of content blocks, each of which has a `type` that determines its shape.

        Example:

        ```json
        [{"type": "text", "text": "Hi, I'm Claude."}]
        ```

        If the request input `messages` ended with an `assistant` turn, then the response `content` will continue directly from that last turn. You can use this to constrain the model's output.

        For example, if the input `messages` were:

        ```json
        [
          {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
          {"role": "assistant", "content": "The best answer is ("}
        ]
        ```

        Then the response `content` might be:

        ```json
        [{"type": "text", "text": "B)"}]
        ```

        - `type TextBlock struct{…}`

          - `Citations []TextCitationUnion`

            Citations supporting the text block.

            The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

            - `type CitationCharLocation struct{…}`

              - `CitedText string`

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndCharIndex int64`

              - `FileID string`

              - `StartCharIndex int64`

              - `Type CharLocation`

                - `const CharLocationCharLocation CharLocation = "char_location"`

            - `type CitationPageLocation struct{…}`

              - `CitedText string`

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndPageNumber int64`

              - `FileID string`

              - `StartPageNumber int64`

              - `Type PageLocation`

                - `const PageLocationPageLocation PageLocation = "page_location"`

            - `type CitationContentBlockLocation struct{…}`

              - `CitedText string`

                The full text of the cited block range, concatenated.

                Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndBlockIndex int64`

                Exclusive 0-based end index of the cited block range in the source's `content` array.

                Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

              - `FileID string`

              - `StartBlockIndex int64`

                0-based index of the first cited block in the source's `content` array.

              - `Type ContentBlockLocation`

                - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

            - `type CitationsWebSearchResultLocation struct{…}`

              - `CitedText string`

              - `EncryptedIndex string`

              - `Title string`

              - `Type WebSearchResultLocation`

                - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

              - `URL string`

            - `type CitationsSearchResultLocation struct{…}`

              - `CitedText string`

                The full text of the cited block range, concatenated.

                Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

              - `EndBlockIndex int64`

                Exclusive 0-based end index of the cited block range in the source's `content` array.

                Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

              - `SearchResultIndex int64`

                0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                Counted separately from `document_index`; server-side web search results are not included in this count.

              - `Source string`

              - `StartBlockIndex int64`

                0-based index of the first cited block in the source's `content` array.

              - `Title string`

              - `Type SearchResultLocation`

                - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

          - `Text string`

          - `Type Text`

            - `const TextText Text = "text"`

        - `type ThinkingBlock struct{…}`

          - `Signature string`

          - `Thinking string`

          - `Type Thinking`

            - `const ThinkingThinking Thinking = "thinking"`

        - `type RedactedThinkingBlock struct{…}`

          - `Data string`

          - `Type RedactedThinking`

            - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

        - `type ToolUseBlock struct{…}`

          - `ID string`

          - `Caller ToolUseBlockCallerUnion`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

              - `Type Direct`

                - `const DirectDirect Direct = "direct"`

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

              - `ToolID string`

              - `Type CodeExecution20250825`

                - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

            - `type ServerToolCaller20260120 struct{…}`

              - `ToolID string`

              - `Type CodeExecution20260120`

                - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

          - `Input map[string, any]`

          - `Name string`

          - `Type ToolUse`

            - `const ToolUseToolUse ToolUse = "tool_use"`

        - `type ServerToolUseBlock struct{…}`

          - `ID string`

          - `Caller ServerToolUseBlockCallerUnion`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

          - `Input map[string, any]`

          - `Name ServerToolUseBlockName`

            - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

            - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

            - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

            - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

            - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

            - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

            - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

          - `Type ServerToolUse`

            - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

        - `type WebSearchToolResultBlock struct{…}`

          - `Caller WebSearchToolResultBlockCallerUnion`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

          - `Content WebSearchToolResultBlockContentUnion`

            - `type WebSearchToolResultError struct{…}`

              - `ErrorCode WebSearchToolResultErrorCode`

                - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

                - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

                - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

                - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

                - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

                - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

              - `Type WebSearchToolResultError`

                - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

            - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

              - `EncryptedContent string`

              - `PageAge string`

              - `Title string`

              - `Type WebSearchResult`

                - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

              - `URL string`

          - `ToolUseID string`

          - `Type WebSearchToolResult`

            - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

        - `type WebFetchToolResultBlock struct{…}`

          - `Caller WebFetchToolResultBlockCallerUnion`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

          - `Content WebFetchToolResultBlockContentUnion`

            - `type WebFetchToolResultErrorBlock struct{…}`

              - `ErrorCode WebFetchToolResultErrorCode`

                - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

                - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

                - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

                - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

                - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

                - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

                - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

                - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

                - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

              - `Type WebFetchToolResultError`

                - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

            - `type WebFetchBlock struct{…}`

              - `Content DocumentBlock`

                - `Citations CitationsConfig`

                  Citation configuration for the document

                  - `Enabled bool`

                - `Source DocumentBlockSourceUnion`

                  - `type Base64PDFSource struct{…}`

                    - `Data string`

                    - `MediaType ApplicationPDF`

                      - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                    - `Type Base64`

                      - `const Base64Base64 Base64 = "base64"`

                  - `type PlainTextSource struct{…}`

                    - `Data string`

                    - `MediaType TextPlain`

                      - `const TextPlainTextPlain TextPlain = "text/plain"`

                    - `Type Text`

                      - `const TextText Text = "text"`

                - `Title string`

                  The title of the document

                - `Type Document`

                  - `const DocumentDocument Document = "document"`

              - `RetrievedAt string`

                ISO 8601 timestamp when the content was retrieved

              - `Type WebFetchResult`

                - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

              - `URL string`

                Fetched content URL

          - `ToolUseID string`

          - `Type WebFetchToolResult`

            - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

        - `type CodeExecutionToolResultBlock struct{…}`

          - `Content CodeExecutionToolResultBlockContentUnion`

            Code execution result with encrypted stdout for PFC + web_search results.

            - `type CodeExecutionToolResultError struct{…}`

              - `ErrorCode CodeExecutionToolResultErrorCode`

                - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

                - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `Type CodeExecutionToolResultError`

                - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

            - `type CodeExecutionResultBlock struct{…}`

              - `Content []CodeExecutionOutputBlock`

                - `FileID string`

                - `Type CodeExecutionOutput`

                  - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

              - `ReturnCode int64`

              - `Stderr string`

              - `Stdout string`

              - `Type CodeExecutionResult`

                - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

            - `type EncryptedCodeExecutionResultBlock struct{…}`

              Code execution result with encrypted stdout for PFC + web_search results.

              - `Content []CodeExecutionOutputBlock`

                - `FileID string`

                - `Type CodeExecutionOutput`

              - `EncryptedStdout string`

              - `ReturnCode int64`

              - `Stderr string`

              - `Type EncryptedCodeExecutionResult`

                - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

          - `ToolUseID string`

          - `Type CodeExecutionToolResult`

            - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

        - `type BashCodeExecutionToolResultBlock struct{…}`

          - `Content BashCodeExecutionToolResultBlockContentUnion`

            - `type BashCodeExecutionToolResultError struct{…}`

              - `ErrorCode BashCodeExecutionToolResultErrorCode`

                - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

                - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

              - `Type BashCodeExecutionToolResultError`

                - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

            - `type BashCodeExecutionResultBlock struct{…}`

              - `Content []BashCodeExecutionOutputBlock`

                - `FileID string`

                - `Type BashCodeExecutionOutput`

                  - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

              - `ReturnCode int64`

              - `Stderr string`

              - `Stdout string`

              - `Type BashCodeExecutionResult`

                - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

          - `ToolUseID string`

          - `Type BashCodeExecutionToolResult`

            - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

        - `type TextEditorCodeExecutionToolResultBlock struct{…}`

          - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

            - `type TextEditorCodeExecutionToolResultError struct{…}`

              - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

                - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

                - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

              - `ErrorMessage string`

              - `Type TextEditorCodeExecutionToolResultError`

                - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

            - `type TextEditorCodeExecutionViewResultBlock struct{…}`

              - `Content string`

              - `FileType TextEditorCodeExecutionViewResultBlockFileType`

                - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

                - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

                - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

              - `NumLines int64`

              - `StartLine int64`

              - `TotalLines int64`

              - `Type TextEditorCodeExecutionViewResult`

                - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

            - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

              - `IsFileUpdate bool`

              - `Type TextEditorCodeExecutionCreateResult`

                - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

            - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

              - `Lines []string`

              - `NewLines int64`

              - `NewStart int64`

              - `OldLines int64`

              - `OldStart int64`

              - `Type TextEditorCodeExecutionStrReplaceResult`

                - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

          - `ToolUseID string`

          - `Type TextEditorCodeExecutionToolResult`

            - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

        - `type ToolSearchToolResultBlock struct{…}`

          - `Content ToolSearchToolResultBlockContentUnion`

            - `type ToolSearchToolResultError struct{…}`

              - `ErrorCode ToolSearchToolResultErrorCode`

                - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

                - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

                - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

                - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

              - `ErrorMessage string`

              - `Type ToolSearchToolResultError`

                - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

            - `type ToolSearchToolSearchResultBlock struct{…}`

              - `ToolReferences []ToolReferenceBlock`

                - `ToolName string`

                - `Type ToolReference`

                  - `const ToolReferenceToolReference ToolReference = "tool_reference"`

              - `Type ToolSearchToolSearchResult`

                - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

          - `ToolUseID string`

          - `Type ToolSearchToolResult`

            - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

        - `type ContainerUploadBlock struct{…}`

          Response model for a file uploaded to the container.

          - `FileID string`

          - `Type ContainerUpload`

            - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

      - `Model Model`

        The model that will complete your prompt.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `type Model string`

          The model that will complete your prompt.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `const ModelClaudeFable5 Model = "claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

            Most capable model for cybersecurity and biology research

          - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

            New class of intelligence, strongest in coding and cybersecurity

          - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

            Frontier intelligence for long-running agents and coding

          - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

          - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

            Exceptional model for specialized complex tasks

          - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

            Exceptional model for specialized complex tasks

          - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

            Powerful model for complex tasks

          - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

            Powerful model for complex tasks

          - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

            High-performance model with extended thinking

          - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

            High-performance model with extended thinking

          - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

            Fast and cost-effective model

        - `string`

      - `Role Assistant`

        Conversational role of the generated message.

        This will always be `"assistant"`.

        - `const AssistantAssistant Assistant = "assistant"`

      - `StopDetails RefusalStopDetails`

        Structured information about a refusal.

        - `Category RefusalStopDetailsCategory`

          The policy category that triggered the refusal.

          `null` when the refusal doesn't map to a named category.

          - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

          - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

          - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

        - `Explanation string`

          Human-readable explanation of the refusal.

          This text is not guaranteed to be stable. `null` when no explanation is available for the category.

        - `Type Refusal`

          - `const RefusalRefusal Refusal = "refusal"`

      - `StopReason StopReason`

        The reason that we stopped.

        This may be one the following values:

        * `"end_turn"`: the model reached a natural stopping point
        * `"max_tokens"`: we exceeded the requested `max_tokens` or the model's maximum
        * `"stop_sequence"`: one of your provided custom `stop_sequences` was generated
        * `"tool_use"`: the model invoked one or more tools
        * `"pause_turn"`: we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
        * `"refusal"`: when streaming classifiers intervene to handle potential policy violations

        In non-streaming mode this value is always non-null. In streaming mode, it is null in the `message_start` event and non-null otherwise.

        - `const StopReasonEndTurn StopReason = "end_turn"`

        - `const StopReasonMaxTokens StopReason = "max_tokens"`

        - `const StopReasonStopSequence StopReason = "stop_sequence"`

        - `const StopReasonToolUse StopReason = "tool_use"`

        - `const StopReasonPauseTurn StopReason = "pause_turn"`

        - `const StopReasonRefusal StopReason = "refusal"`

      - `StopSequence string`

        Which custom stop sequence was generated, if any.

        This value will be a non-null string if one of your custom stop sequences was generated.

      - `Type Message`

        Object type.

        For Messages, this is always `"message"`.

        - `const MessageMessage Message = "message"`

      - `Usage Usage`

        Billing and rate-limit usage.

        Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

        Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

        For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

        Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

        - `CacheCreation CacheCreation`

          Breakdown of cached tokens by TTL

          - `Ephemeral1hInputTokens int64`

            The number of input tokens used to create the 1 hour cache entry.

          - `Ephemeral5mInputTokens int64`

            The number of input tokens used to create the 5 minute cache entry.

        - `CacheCreationInputTokens int64`

          The number of input tokens used to create the cache entry.

        - `CacheReadInputTokens int64`

          The number of input tokens read from the cache.

        - `InferenceGeo string`

          The geographic region where inference was performed for this request.

        - `InputTokens int64`

          The number of input tokens which were used.

        - `OutputTokens int64`

          The number of output tokens which were used.

        - `OutputTokensDetails OutputTokensDetails`

          Breakdown of output tokens by category.

          `output_tokens` remains the inclusive, authoritative total used for billing.
          This object provides a read-only decomposition for observability — for example,
          how many of the billed output tokens were spent on internal reasoning that may
          have been summarized before being returned to you.

          - `ThinkingTokens int64`

            Number of output tokens the model generated as internal reasoning, including
            the thinking-block delimiter tokens.

            Reflects the raw reasoning the model produced, not the (possibly shorter)
            summarized thinking text returned in the response body. Computed by
            re-tokenizing the raw reasoning text, so it may differ from the model's exact
            generation count by a small number of tokens. Always ≤ `output_tokens`;
            `output_tokens - thinking_tokens` approximates the non-reasoning output.

        - `ServerToolUse ServerToolUsage`

          The number of server tool requests.

          - `WebFetchRequests int64`

            The number of web fetch tool requests.

          - `WebSearchRequests int64`

            The number of web search tool requests.

        - `ServiceTier UsageServiceTier`

          If the request used the priority, standard, or batch tier.

          - `const UsageServiceTierStandard UsageServiceTier = "standard"`

          - `const UsageServiceTierPriority UsageServiceTier = "priority"`

          - `const UsageServiceTierBatch UsageServiceTier = "batch"`

    - `Type MessageStart`

      - `const MessageStartMessageStart MessageStart = "message_start"`

  - `type MessageDeltaEvent struct{…}`

    - `Delta MessageDeltaEventDelta`

      - `Container Container`

        Information about the container used in the request (for the code execution tool)

      - `StopDetails RefusalStopDetails`

        Structured information about a refusal.

      - `StopReason StopReason`

      - `StopSequence string`

    - `Type MessageDelta`

      - `const MessageDeltaMessageDelta MessageDelta = "message_delta"`

    - `Usage MessageDeltaUsage`

      Billing and rate-limit usage.

      Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

      Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

      For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

      Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

      - `CacheCreationInputTokens int64`

        The cumulative number of input tokens used to create the cache entry.

      - `CacheReadInputTokens int64`

        The cumulative number of input tokens read from the cache.

      - `InputTokens int64`

        The cumulative number of input tokens which were used.

      - `OutputTokens int64`

        The cumulative number of output tokens which were used.

      - `OutputTokensDetails OutputTokensDetails`

        Breakdown of output tokens by category.

        `output_tokens` remains the inclusive, authoritative total used for billing.
        This object provides a read-only decomposition for observability — for example,
        how many of the billed output tokens were spent on internal reasoning that may
        have been summarized before being returned to you.

      - `ServerToolUse ServerToolUsage`

        The number of server tool requests.

  - `type MessageStopEvent struct{…}`

    - `Type MessageStop`

      - `const MessageStopMessageStop MessageStop = "message_stop"`

  - `type ContentBlockStartEvent struct{…}`

    - `ContentBlock ContentBlockStartEventContentBlockUnion`

      Response model for a file uploaded to the container.

      - `type TextBlock struct{…}`

      - `type ThinkingBlock struct{…}`

      - `type RedactedThinkingBlock struct{…}`

      - `type ToolUseBlock struct{…}`

      - `type ServerToolUseBlock struct{…}`

      - `type WebSearchToolResultBlock struct{…}`

      - `type WebFetchToolResultBlock struct{…}`

      - `type CodeExecutionToolResultBlock struct{…}`

      - `type BashCodeExecutionToolResultBlock struct{…}`

      - `type TextEditorCodeExecutionToolResultBlock struct{…}`

      - `type ToolSearchToolResultBlock struct{…}`

      - `type ContainerUploadBlock struct{…}`

        Response model for a file uploaded to the container.

    - `Index int64`

    - `Type ContentBlockStart`

      - `const ContentBlockStartContentBlockStart ContentBlockStart = "content_block_start"`

  - `type ContentBlockDeltaEvent struct{…}`

    - `Delta RawContentBlockDeltaUnion`

      - `type TextDelta struct{…}`

        - `Text string`

        - `Type TextDelta`

          - `const TextDeltaTextDelta TextDelta = "text_delta"`

      - `type InputJSONDelta struct{…}`

        - `PartialJSON string`

        - `Type InputJSONDelta`

          - `const InputJSONDeltaInputJSONDelta InputJSONDelta = "input_json_delta"`

      - `type CitationsDelta struct{…}`

        - `Citation CitationsDeltaCitationUnion`

          - `type CitationCharLocation struct{…}`

          - `type CitationPageLocation struct{…}`

          - `type CitationContentBlockLocation struct{…}`

          - `type CitationsWebSearchResultLocation struct{…}`

          - `type CitationsSearchResultLocation struct{…}`

        - `Type CitationsDelta`

          - `const CitationsDeltaCitationsDelta CitationsDelta = "citations_delta"`

      - `type ThinkingDelta struct{…}`

        - `Thinking string`

        - `Type ThinkingDelta`

          - `const ThinkingDeltaThinkingDelta ThinkingDelta = "thinking_delta"`

      - `type SignatureDelta struct{…}`

        - `Signature string`

        - `Type SignatureDelta`

          - `const SignatureDeltaSignatureDelta SignatureDelta = "signature_delta"`

    - `Index int64`

    - `Type ContentBlockDelta`

      - `const ContentBlockDeltaContentBlockDelta ContentBlockDelta = "content_block_delta"`

  - `type ContentBlockStopEvent struct{…}`

    - `Index int64`

    - `Type ContentBlockStop`

      - `const ContentBlockStopContentBlockStop ContentBlockStop = "content_block_stop"`

### Redacted Thinking Block

- `type RedactedThinkingBlock struct{…}`

  - `Data string`

  - `Type RedactedThinking`

    - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

### Redacted Thinking Block Param

- `type RedactedThinkingBlockParamResp struct{…}`

  - `Data string`

  - `Type RedactedThinking`

    - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

### Refusal Stop Details

- `type RefusalStopDetails struct{…}`

  Structured information about a refusal.

  - `Category RefusalStopDetailsCategory`

    The policy category that triggered the refusal.

    `null` when the refusal doesn't map to a named category.

    - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

    - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

    - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

  - `Explanation string`

    Human-readable explanation of the refusal.

    This text is not guaranteed to be stable. `null` when no explanation is available for the category.

  - `Type Refusal`

    - `const RefusalRefusal Refusal = "refusal"`

### Search Result Block Param

- `type SearchResultBlockParamResp struct{…}`

  - `Content []TextBlockParamResp`

    - `Text string`

    - `Type Text`

      - `const TextText Text = "text"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

      - `Type Ephemeral`

        - `const EphemeralEphemeral Ephemeral = "ephemeral"`

      - `TTL CacheControlEphemeralTTL`

        The time-to-live for the cache control breakpoint.

        This may be one the following values:

        - `5m`: 5 minutes
        - `1h`: 1 hour

        Defaults to `5m`.

        - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

        - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

    - `Citations []TextCitationParamUnionResp`

      - `type CitationCharLocationParamResp struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndCharIndex int64`

        - `StartCharIndex int64`

        - `Type CharLocation`

          - `const CharLocationCharLocation CharLocation = "char_location"`

      - `type CitationPageLocationParamResp struct{…}`

        - `CitedText string`

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndPageNumber int64`

        - `StartPageNumber int64`

        - `Type PageLocation`

          - `const PageLocationPageLocation PageLocation = "page_location"`

      - `type CitationContentBlockLocationParamResp struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `DocumentIndex int64`

        - `DocumentTitle string`

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Type ContentBlockLocation`

          - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

      - `type CitationWebSearchResultLocationParamResp struct{…}`

        - `CitedText string`

        - `EncryptedIndex string`

        - `Title string`

        - `Type WebSearchResultLocation`

          - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

        - `URL string`

      - `type CitationSearchResultLocationParamResp struct{…}`

        - `CitedText string`

          The full text of the cited block range, concatenated.

          Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

        - `EndBlockIndex int64`

          Exclusive 0-based end index of the cited block range in the source's `content` array.

          Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

        - `SearchResultIndex int64`

          0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

          Counted separately from `document_index`; server-side web search results are not included in this count.

        - `Source string`

        - `StartBlockIndex int64`

          0-based index of the first cited block in the source's `content` array.

        - `Title string`

        - `Type SearchResultLocation`

          - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

  - `Source string`

  - `Title string`

  - `Type SearchResult`

    - `const SearchResultSearchResult SearchResult = "search_result"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

  - `Citations CitationsConfigParamResp`

    - `Enabled bool`

### Server Tool Caller

- `type ServerToolCaller struct{…}`

  Tool invocation generated by a server-side tool.

  - `ToolID string`

  - `Type CodeExecution20250825`

    - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

### Server Tool Caller 20260120

- `type ServerToolCaller20260120 struct{…}`

  - `ToolID string`

  - `Type CodeExecution20260120`

    - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

### Server Tool Usage

- `type ServerToolUsage struct{…}`

  - `WebFetchRequests int64`

    The number of web fetch tool requests.

  - `WebSearchRequests int64`

    The number of web search tool requests.

### Server Tool Use Block

- `type ServerToolUseBlock struct{…}`

  - `ID string`

  - `Caller ServerToolUseBlockCallerUnion`

    Tool invocation directly from the model.

    - `type DirectCaller struct{…}`

      Tool invocation directly from the model.

      - `Type Direct`

        - `const DirectDirect Direct = "direct"`

    - `type ServerToolCaller struct{…}`

      Tool invocation generated by a server-side tool.

      - `ToolID string`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `type ServerToolCaller20260120 struct{…}`

      - `ToolID string`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

  - `Input map[string, any]`

  - `Name ServerToolUseBlockName`

    - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

    - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

    - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

    - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

    - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

    - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

    - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

  - `Type ServerToolUse`

    - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

### Server Tool Use Block Param

- `type ServerToolUseBlockParamResp struct{…}`

  - `ID string`

  - `Input map[string, any]`

  - `Name ServerToolUseBlockParamName`

    - `const ServerToolUseBlockParamNameWebSearch ServerToolUseBlockParamName = "web_search"`

    - `const ServerToolUseBlockParamNameWebFetch ServerToolUseBlockParamName = "web_fetch"`

    - `const ServerToolUseBlockParamNameCodeExecution ServerToolUseBlockParamName = "code_execution"`

    - `const ServerToolUseBlockParamNameBashCodeExecution ServerToolUseBlockParamName = "bash_code_execution"`

    - `const ServerToolUseBlockParamNameTextEditorCodeExecution ServerToolUseBlockParamName = "text_editor_code_execution"`

    - `const ServerToolUseBlockParamNameToolSearchToolRegex ServerToolUseBlockParamName = "tool_search_tool_regex"`

    - `const ServerToolUseBlockParamNameToolSearchToolBm25 ServerToolUseBlockParamName = "tool_search_tool_bm25"`

  - `Type ServerToolUse`

    - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `Caller ServerToolUseBlockParamCallerUnionResp`

    Tool invocation directly from the model.

    - `type DirectCaller struct{…}`

      Tool invocation directly from the model.

      - `Type Direct`

        - `const DirectDirect Direct = "direct"`

    - `type ServerToolCaller struct{…}`

      Tool invocation generated by a server-side tool.

      - `ToolID string`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `type ServerToolCaller20260120 struct{…}`

      - `ToolID string`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

### Signature Delta

- `type SignatureDelta struct{…}`

  - `Signature string`

  - `Type SignatureDelta`

    - `const SignatureDeltaSignatureDelta SignatureDelta = "signature_delta"`

### Stop Reason

- `type StopReason string`

  - `const StopReasonEndTurn StopReason = "end_turn"`

  - `const StopReasonMaxTokens StopReason = "max_tokens"`

  - `const StopReasonStopSequence StopReason = "stop_sequence"`

  - `const StopReasonToolUse StopReason = "tool_use"`

  - `const StopReasonPauseTurn StopReason = "pause_turn"`

  - `const StopReasonRefusal StopReason = "refusal"`

### Text Block

- `type TextBlock struct{…}`

  - `Citations []TextCitationUnion`

    Citations supporting the text block.

    The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

    - `type CitationCharLocation struct{…}`

      - `CitedText string`

      - `DocumentIndex int64`

      - `DocumentTitle string`

      - `EndCharIndex int64`

      - `FileID string`

      - `StartCharIndex int64`

      - `Type CharLocation`

        - `const CharLocationCharLocation CharLocation = "char_location"`

    - `type CitationPageLocation struct{…}`

      - `CitedText string`

      - `DocumentIndex int64`

      - `DocumentTitle string`

      - `EndPageNumber int64`

      - `FileID string`

      - `StartPageNumber int64`

      - `Type PageLocation`

        - `const PageLocationPageLocation PageLocation = "page_location"`

    - `type CitationContentBlockLocation struct{…}`

      - `CitedText string`

        The full text of the cited block range, concatenated.

        Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

      - `DocumentIndex int64`

      - `DocumentTitle string`

      - `EndBlockIndex int64`

        Exclusive 0-based end index of the cited block range in the source's `content` array.

        Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

      - `FileID string`

      - `StartBlockIndex int64`

        0-based index of the first cited block in the source's `content` array.

      - `Type ContentBlockLocation`

        - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

    - `type CitationsWebSearchResultLocation struct{…}`

      - `CitedText string`

      - `EncryptedIndex string`

      - `Title string`

      - `Type WebSearchResultLocation`

        - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

      - `URL string`

    - `type CitationsSearchResultLocation struct{…}`

      - `CitedText string`

        The full text of the cited block range, concatenated.

        Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

      - `EndBlockIndex int64`

        Exclusive 0-based end index of the cited block range in the source's `content` array.

        Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

      - `SearchResultIndex int64`

        0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

        Counted separately from `document_index`; server-side web search results are not included in this count.

      - `Source string`

      - `StartBlockIndex int64`

        0-based index of the first cited block in the source's `content` array.

      - `Title string`

      - `Type SearchResultLocation`

        - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

  - `Text string`

  - `Type Text`

    - `const TextText Text = "text"`

### Text Block Param

- `type TextBlockParamResp struct{…}`

  - `Text string`

  - `Type Text`

    - `const TextText Text = "text"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `Citations []TextCitationParamUnionResp`

    - `type CitationCharLocationParamResp struct{…}`

      - `CitedText string`

      - `DocumentIndex int64`

      - `DocumentTitle string`

      - `EndCharIndex int64`

      - `StartCharIndex int64`

      - `Type CharLocation`

        - `const CharLocationCharLocation CharLocation = "char_location"`

    - `type CitationPageLocationParamResp struct{…}`

      - `CitedText string`

      - `DocumentIndex int64`

      - `DocumentTitle string`

      - `EndPageNumber int64`

      - `StartPageNumber int64`

      - `Type PageLocation`

        - `const PageLocationPageLocation PageLocation = "page_location"`

    - `type CitationContentBlockLocationParamResp struct{…}`

      - `CitedText string`

        The full text of the cited block range, concatenated.

        Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

      - `DocumentIndex int64`

      - `DocumentTitle string`

      - `EndBlockIndex int64`

        Exclusive 0-based end index of the cited block range in the source's `content` array.

        Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

      - `StartBlockIndex int64`

        0-based index of the first cited block in the source's `content` array.

      - `Type ContentBlockLocation`

        - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

    - `type CitationWebSearchResultLocationParamResp struct{…}`

      - `CitedText string`

      - `EncryptedIndex string`

      - `Title string`

      - `Type WebSearchResultLocation`

        - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

      - `URL string`

    - `type CitationSearchResultLocationParamResp struct{…}`

      - `CitedText string`

        The full text of the cited block range, concatenated.

        Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

      - `EndBlockIndex int64`

        Exclusive 0-based end index of the cited block range in the source's `content` array.

        Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

      - `SearchResultIndex int64`

        0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

        Counted separately from `document_index`; server-side web search results are not included in this count.

      - `Source string`

      - `StartBlockIndex int64`

        0-based index of the first cited block in the source's `content` array.

      - `Title string`

      - `Type SearchResultLocation`

        - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

### Text Citation

- `type TextCitationUnion interface{…}`

  - `type CitationCharLocation struct{…}`

    - `CitedText string`

    - `DocumentIndex int64`

    - `DocumentTitle string`

    - `EndCharIndex int64`

    - `FileID string`

    - `StartCharIndex int64`

    - `Type CharLocation`

      - `const CharLocationCharLocation CharLocation = "char_location"`

  - `type CitationPageLocation struct{…}`

    - `CitedText string`

    - `DocumentIndex int64`

    - `DocumentTitle string`

    - `EndPageNumber int64`

    - `FileID string`

    - `StartPageNumber int64`

    - `Type PageLocation`

      - `const PageLocationPageLocation PageLocation = "page_location"`

  - `type CitationContentBlockLocation struct{…}`

    - `CitedText string`

      The full text of the cited block range, concatenated.

      Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

    - `DocumentIndex int64`

    - `DocumentTitle string`

    - `EndBlockIndex int64`

      Exclusive 0-based end index of the cited block range in the source's `content` array.

      Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

    - `FileID string`

    - `StartBlockIndex int64`

      0-based index of the first cited block in the source's `content` array.

    - `Type ContentBlockLocation`

      - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

  - `type CitationsWebSearchResultLocation struct{…}`

    - `CitedText string`

    - `EncryptedIndex string`

    - `Title string`

    - `Type WebSearchResultLocation`

      - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

    - `URL string`

  - `type CitationsSearchResultLocation struct{…}`

    - `CitedText string`

      The full text of the cited block range, concatenated.

      Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

    - `EndBlockIndex int64`

      Exclusive 0-based end index of the cited block range in the source's `content` array.

      Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

    - `SearchResultIndex int64`

      0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

      Counted separately from `document_index`; server-side web search results are not included in this count.

    - `Source string`

    - `StartBlockIndex int64`

      0-based index of the first cited block in the source's `content` array.

    - `Title string`

    - `Type SearchResultLocation`

      - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

### Text Citation Param

- `type TextCitationParamUnionResp interface{…}`

  - `type CitationCharLocationParamResp struct{…}`

    - `CitedText string`

    - `DocumentIndex int64`

    - `DocumentTitle string`

    - `EndCharIndex int64`

    - `StartCharIndex int64`

    - `Type CharLocation`

      - `const CharLocationCharLocation CharLocation = "char_location"`

  - `type CitationPageLocationParamResp struct{…}`

    - `CitedText string`

    - `DocumentIndex int64`

    - `DocumentTitle string`

    - `EndPageNumber int64`

    - `StartPageNumber int64`

    - `Type PageLocation`

      - `const PageLocationPageLocation PageLocation = "page_location"`

  - `type CitationContentBlockLocationParamResp struct{…}`

    - `CitedText string`

      The full text of the cited block range, concatenated.

      Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

    - `DocumentIndex int64`

    - `DocumentTitle string`

    - `EndBlockIndex int64`

      Exclusive 0-based end index of the cited block range in the source's `content` array.

      Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

    - `StartBlockIndex int64`

      0-based index of the first cited block in the source's `content` array.

    - `Type ContentBlockLocation`

      - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

  - `type CitationWebSearchResultLocationParamResp struct{…}`

    - `CitedText string`

    - `EncryptedIndex string`

    - `Title string`

    - `Type WebSearchResultLocation`

      - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

    - `URL string`

  - `type CitationSearchResultLocationParamResp struct{…}`

    - `CitedText string`

      The full text of the cited block range, concatenated.

      Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

    - `EndBlockIndex int64`

      Exclusive 0-based end index of the cited block range in the source's `content` array.

      Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

    - `SearchResultIndex int64`

      0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

      Counted separately from `document_index`; server-side web search results are not included in this count.

    - `Source string`

    - `StartBlockIndex int64`

      0-based index of the first cited block in the source's `content` array.

    - `Title string`

    - `Type SearchResultLocation`

      - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

### Text Delta

- `type TextDelta struct{…}`

  - `Text string`

  - `Type TextDelta`

    - `const TextDeltaTextDelta TextDelta = "text_delta"`

### Text Editor Code Execution Create Result Block

- `type TextEditorCodeExecutionCreateResultBlock struct{…}`

  - `IsFileUpdate bool`

  - `Type TextEditorCodeExecutionCreateResult`

    - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

### Text Editor Code Execution Create Result Block Param

- `type TextEditorCodeExecutionCreateResultBlockParamResp struct{…}`

  - `IsFileUpdate bool`

  - `Type TextEditorCodeExecutionCreateResult`

    - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

### Text Editor Code Execution Str Replace Result Block

- `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

  - `Lines []string`

  - `NewLines int64`

  - `NewStart int64`

  - `OldLines int64`

  - `OldStart int64`

  - `Type TextEditorCodeExecutionStrReplaceResult`

    - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

### Text Editor Code Execution Str Replace Result Block Param

- `type TextEditorCodeExecutionStrReplaceResultBlockParamResp struct{…}`

  - `Type TextEditorCodeExecutionStrReplaceResult`

    - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

  - `Lines []string`

  - `NewLines int64`

  - `NewStart int64`

  - `OldLines int64`

  - `OldStart int64`

### Text Editor Code Execution Tool Result Block

- `type TextEditorCodeExecutionToolResultBlock struct{…}`

  - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

    - `type TextEditorCodeExecutionToolResultError struct{…}`

      - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

        - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

        - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

        - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

        - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

        - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

      - `ErrorMessage string`

      - `Type TextEditorCodeExecutionToolResultError`

        - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

    - `type TextEditorCodeExecutionViewResultBlock struct{…}`

      - `Content string`

      - `FileType TextEditorCodeExecutionViewResultBlockFileType`

        - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

        - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

        - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

      - `NumLines int64`

      - `StartLine int64`

      - `TotalLines int64`

      - `Type TextEditorCodeExecutionViewResult`

        - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

    - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

      - `IsFileUpdate bool`

      - `Type TextEditorCodeExecutionCreateResult`

        - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

    - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

      - `Lines []string`

      - `NewLines int64`

      - `NewStart int64`

      - `OldLines int64`

      - `OldStart int64`

      - `Type TextEditorCodeExecutionStrReplaceResult`

        - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

  - `ToolUseID string`

  - `Type TextEditorCodeExecutionToolResult`

    - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

### Text Editor Code Execution Tool Result Block Param

- `type TextEditorCodeExecutionToolResultBlockParamResp struct{…}`

  - `Content TextEditorCodeExecutionToolResultBlockParamContentUnionResp`

    - `type TextEditorCodeExecutionToolResultErrorParamResp struct{…}`

      - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

        - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

        - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

        - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

        - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

        - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

      - `Type TextEditorCodeExecutionToolResultError`

        - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

      - `ErrorMessage string`

    - `type TextEditorCodeExecutionViewResultBlockParamResp struct{…}`

      - `Content string`

      - `FileType TextEditorCodeExecutionViewResultBlockParamFileType`

        - `const TextEditorCodeExecutionViewResultBlockParamFileTypeText TextEditorCodeExecutionViewResultBlockParamFileType = "text"`

        - `const TextEditorCodeExecutionViewResultBlockParamFileTypeImage TextEditorCodeExecutionViewResultBlockParamFileType = "image"`

        - `const TextEditorCodeExecutionViewResultBlockParamFileTypePDF TextEditorCodeExecutionViewResultBlockParamFileType = "pdf"`

      - `Type TextEditorCodeExecutionViewResult`

        - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

      - `NumLines int64`

      - `StartLine int64`

      - `TotalLines int64`

    - `type TextEditorCodeExecutionCreateResultBlockParamResp struct{…}`

      - `IsFileUpdate bool`

      - `Type TextEditorCodeExecutionCreateResult`

        - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

    - `type TextEditorCodeExecutionStrReplaceResultBlockParamResp struct{…}`

      - `Type TextEditorCodeExecutionStrReplaceResult`

        - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

      - `Lines []string`

      - `NewLines int64`

      - `NewStart int64`

      - `OldLines int64`

      - `OldStart int64`

  - `ToolUseID string`

  - `Type TextEditorCodeExecutionToolResult`

    - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

### Text Editor Code Execution Tool Result Error

- `type TextEditorCodeExecutionToolResultError struct{…}`

  - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

    - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

    - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

    - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

    - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

    - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

  - `ErrorMessage string`

  - `Type TextEditorCodeExecutionToolResultError`

    - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

### Text Editor Code Execution Tool Result Error Code

- `type TextEditorCodeExecutionToolResultErrorCode string`

  - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

  - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

  - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

  - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

  - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

### Text Editor Code Execution Tool Result Error Param

- `type TextEditorCodeExecutionToolResultErrorParamResp struct{…}`

  - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

    - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

    - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

    - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

    - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

    - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

  - `Type TextEditorCodeExecutionToolResultError`

    - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

  - `ErrorMessage string`

### Text Editor Code Execution View Result Block

- `type TextEditorCodeExecutionViewResultBlock struct{…}`

  - `Content string`

  - `FileType TextEditorCodeExecutionViewResultBlockFileType`

    - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

    - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

    - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

  - `NumLines int64`

  - `StartLine int64`

  - `TotalLines int64`

  - `Type TextEditorCodeExecutionViewResult`

    - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

### Text Editor Code Execution View Result Block Param

- `type TextEditorCodeExecutionViewResultBlockParamResp struct{…}`

  - `Content string`

  - `FileType TextEditorCodeExecutionViewResultBlockParamFileType`

    - `const TextEditorCodeExecutionViewResultBlockParamFileTypeText TextEditorCodeExecutionViewResultBlockParamFileType = "text"`

    - `const TextEditorCodeExecutionViewResultBlockParamFileTypeImage TextEditorCodeExecutionViewResultBlockParamFileType = "image"`

    - `const TextEditorCodeExecutionViewResultBlockParamFileTypePDF TextEditorCodeExecutionViewResultBlockParamFileType = "pdf"`

  - `Type TextEditorCodeExecutionViewResult`

    - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

  - `NumLines int64`

  - `StartLine int64`

  - `TotalLines int64`

### Thinking Block

- `type ThinkingBlock struct{…}`

  - `Signature string`

  - `Thinking string`

  - `Type Thinking`

    - `const ThinkingThinking Thinking = "thinking"`

### Thinking Block Param

- `type ThinkingBlockParamResp struct{…}`

  - `Signature string`

  - `Thinking string`

  - `Type Thinking`

    - `const ThinkingThinking Thinking = "thinking"`

### Thinking Config Adaptive

- `type ThinkingConfigAdaptive struct{…}`

  - `Type Adaptive`

    - `const AdaptiveAdaptive Adaptive = "adaptive"`

  - `Display ThinkingConfigAdaptiveDisplay`

    Controls how thinking content appears in the response. When set to `summarized`, thinking is returned normally. When set to `omitted`, thinking content is redacted but a signature is returned for multi-turn continuity. Defaults to `summarized`.

    - `const ThinkingConfigAdaptiveDisplaySummarized ThinkingConfigAdaptiveDisplay = "summarized"`

    - `const ThinkingConfigAdaptiveDisplayOmitted ThinkingConfigAdaptiveDisplay = "omitted"`

### Thinking Config Disabled

- `type ThinkingConfigDisabled struct{…}`

  - `Type Disabled`

    - `const DisabledDisabled Disabled = "disabled"`

### Thinking Config Enabled

- `type ThinkingConfigEnabled struct{…}`

  - `BudgetTokens int64`

    Determines how many tokens Claude can use for its internal reasoning process. Larger budgets can enable more thorough analysis for complex problems, improving response quality.

    Must be ≥1024 and less than `max_tokens`.

    See [extended thinking](https://docs.claude.com/en/docs/build-with-claude/extended-thinking) for details.

  - `Type Enabled`

    - `const EnabledEnabled Enabled = "enabled"`

  - `Display ThinkingConfigEnabledDisplay`

    Controls how thinking content appears in the response. When set to `summarized`, thinking is returned normally. When set to `omitted`, thinking content is redacted but a signature is returned for multi-turn continuity. Defaults to `summarized`.

    - `const ThinkingConfigEnabledDisplaySummarized ThinkingConfigEnabledDisplay = "summarized"`

    - `const ThinkingConfigEnabledDisplayOmitted ThinkingConfigEnabledDisplay = "omitted"`

### Thinking Config Param

- `type ThinkingConfigParamUnionResp interface{…}`

  Configuration for enabling Claude's extended thinking.

  When enabled, responses include `thinking` content blocks showing Claude's thinking process before the final answer. Requires a minimum budget of 1,024 tokens and counts towards your `max_tokens` limit.

  See [extended thinking](https://docs.claude.com/en/docs/build-with-claude/extended-thinking) for details.

  - `type ThinkingConfigEnabled struct{…}`

    - `BudgetTokens int64`

      Determines how many tokens Claude can use for its internal reasoning process. Larger budgets can enable more thorough analysis for complex problems, improving response quality.

      Must be ≥1024 and less than `max_tokens`.

      See [extended thinking](https://docs.claude.com/en/docs/build-with-claude/extended-thinking) for details.

    - `Type Enabled`

      - `const EnabledEnabled Enabled = "enabled"`

    - `Display ThinkingConfigEnabledDisplay`

      Controls how thinking content appears in the response. When set to `summarized`, thinking is returned normally. When set to `omitted`, thinking content is redacted but a signature is returned for multi-turn continuity. Defaults to `summarized`.

      - `const ThinkingConfigEnabledDisplaySummarized ThinkingConfigEnabledDisplay = "summarized"`

      - `const ThinkingConfigEnabledDisplayOmitted ThinkingConfigEnabledDisplay = "omitted"`

  - `type ThinkingConfigDisabled struct{…}`

    - `Type Disabled`

      - `const DisabledDisabled Disabled = "disabled"`

  - `type ThinkingConfigAdaptive struct{…}`

    - `Type Adaptive`

      - `const AdaptiveAdaptive Adaptive = "adaptive"`

    - `Display ThinkingConfigAdaptiveDisplay`

      Controls how thinking content appears in the response. When set to `summarized`, thinking is returned normally. When set to `omitted`, thinking content is redacted but a signature is returned for multi-turn continuity. Defaults to `summarized`.

      - `const ThinkingConfigAdaptiveDisplaySummarized ThinkingConfigAdaptiveDisplay = "summarized"`

      - `const ThinkingConfigAdaptiveDisplayOmitted ThinkingConfigAdaptiveDisplay = "omitted"`

### Thinking Delta

- `type ThinkingDelta struct{…}`

  - `Thinking string`

  - `Type ThinkingDelta`

    - `const ThinkingDeltaThinkingDelta ThinkingDelta = "thinking_delta"`

### Tool

- `type Tool struct{…}`

  - `InputSchema ToolInputSchema`

    [JSON schema](https://json-schema.org/draft/2020-12) for this tool's input.

    This defines the shape of the `input` that your tool accepts and that the model will produce.

    - `Type Object`

      - `const ObjectObject Object = "object"`

    - `Properties map[string, any]`

    - `Required []string`

  - `Name string`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

  - `AllowedCallers []string`

    - `const ToolAllowedCallerDirect ToolAllowedCaller = "direct"`

    - `const ToolAllowedCallerCodeExecution20250825 ToolAllowedCaller = "code_execution_20250825"`

    - `const ToolAllowedCallerCodeExecution20260120 ToolAllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `Description string`

    Description of what this tool does.

    Tool descriptions should be as detailed as possible. The more information that the model has about what the tool is and how to use it, the better it will perform. You can use natural language descriptions to reinforce important aspects of the tool input JSON schema.

  - `EagerInputStreaming bool`

    Enable eager input streaming for this tool. When true, tool input parameters will be streamed incrementally as they are generated, and types will be inferred on-the-fly rather than buffering the full JSON output. When false, streaming is disabled for this tool even if the fine-grained-tool-streaming beta is active. When null (default), uses the default behavior based on beta headers.

  - `InputExamples []map[string, any]`

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

  - `Type ToolType`

    - `const ToolTypeCustom ToolType = "custom"`

### Tool Bash 20250124

- `type ToolBash20250124 struct{…}`

  - `Name Bash`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const BashBash Bash = "bash"`

  - `Type Bash20250124`

    - `const Bash20250124Bash20250124 Bash20250124 = "bash_20250124"`

  - `AllowedCallers []string`

    - `const ToolBash20250124AllowedCallerDirect ToolBash20250124AllowedCaller = "direct"`

    - `const ToolBash20250124AllowedCallerCodeExecution20250825 ToolBash20250124AllowedCaller = "code_execution_20250825"`

    - `const ToolBash20250124AllowedCallerCodeExecution20260120 ToolBash20250124AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `InputExamples []map[string, any]`

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Tool Choice

- `type ToolChoiceUnion interface{…}`

  How the model should use the provided tools. The model can use a specific tool, any available tool, decide by itself, or not use tools at all.

  - `type ToolChoiceAuto struct{…}`

    The model will automatically decide whether to use tools.

    - `Type Auto`

      - `const AutoAuto Auto = "auto"`

    - `DisableParallelToolUse bool`

      Whether to disable parallel tool use.

      Defaults to `false`. If set to `true`, the model will output at most one tool use.

  - `type ToolChoiceAny struct{…}`

    The model will use any available tools.

    - `Type Any`

      - `const AnyAny Any = "any"`

    - `DisableParallelToolUse bool`

      Whether to disable parallel tool use.

      Defaults to `false`. If set to `true`, the model will output exactly one tool use.

  - `type ToolChoiceTool struct{…}`

    The model will use the specified tool with `tool_choice.name`.

    - `Name string`

      The name of the tool to use.

    - `Type Tool`

      - `const ToolTool Tool = "tool"`

    - `DisableParallelToolUse bool`

      Whether to disable parallel tool use.

      Defaults to `false`. If set to `true`, the model will output exactly one tool use.

  - `type ToolChoiceNone struct{…}`

    The model will not be allowed to use tools.

    - `Type None`

      - `const NoneNone None = "none"`

### Tool Choice Any

- `type ToolChoiceAny struct{…}`

  The model will use any available tools.

  - `Type Any`

    - `const AnyAny Any = "any"`

  - `DisableParallelToolUse bool`

    Whether to disable parallel tool use.

    Defaults to `false`. If set to `true`, the model will output exactly one tool use.

### Tool Choice Auto

- `type ToolChoiceAuto struct{…}`

  The model will automatically decide whether to use tools.

  - `Type Auto`

    - `const AutoAuto Auto = "auto"`

  - `DisableParallelToolUse bool`

    Whether to disable parallel tool use.

    Defaults to `false`. If set to `true`, the model will output at most one tool use.

### Tool Choice None

- `type ToolChoiceNone struct{…}`

  The model will not be allowed to use tools.

  - `Type None`

    - `const NoneNone None = "none"`

### Tool Choice Tool

- `type ToolChoiceTool struct{…}`

  The model will use the specified tool with `tool_choice.name`.

  - `Name string`

    The name of the tool to use.

  - `Type Tool`

    - `const ToolTool Tool = "tool"`

  - `DisableParallelToolUse bool`

    Whether to disable parallel tool use.

    Defaults to `false`. If set to `true`, the model will output exactly one tool use.

### Tool Reference Block

- `type ToolReferenceBlock struct{…}`

  - `ToolName string`

  - `Type ToolReference`

    - `const ToolReferenceToolReference ToolReference = "tool_reference"`

### Tool Reference Block Param

- `type ToolReferenceBlockParamResp struct{…}`

  Tool reference block that can be included in tool_result content.

  - `ToolName string`

  - `Type ToolReference`

    - `const ToolReferenceToolReference ToolReference = "tool_reference"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

### Tool Result Block Param

- `type ToolResultBlockParamResp struct{…}`

  - `ToolUseID string`

  - `Type ToolResult`

    - `const ToolResultToolResult ToolResult = "tool_result"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `Content []ToolResultBlockParamContentUnionResp`

    - `[]ToolResultBlockParamContentUnionResp`

      - `type TextBlockParamResp struct{…}`

        - `Text string`

        - `Type Text`

          - `const TextText Text = "text"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Citations []TextCitationParamUnionResp`

          - `type CitationCharLocationParamResp struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndCharIndex int64`

            - `StartCharIndex int64`

            - `Type CharLocation`

              - `const CharLocationCharLocation CharLocation = "char_location"`

          - `type CitationPageLocationParamResp struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndPageNumber int64`

            - `StartPageNumber int64`

            - `Type PageLocation`

              - `const PageLocationPageLocation PageLocation = "page_location"`

          - `type CitationContentBlockLocationParamResp struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Type ContentBlockLocation`

              - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

          - `type CitationWebSearchResultLocationParamResp struct{…}`

            - `CitedText string`

            - `EncryptedIndex string`

            - `Title string`

            - `Type WebSearchResultLocation`

              - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

            - `URL string`

          - `type CitationSearchResultLocationParamResp struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `SearchResultIndex int64`

              0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

              Counted separately from `document_index`; server-side web search results are not included in this count.

            - `Source string`

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Title string`

            - `Type SearchResultLocation`

              - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

      - `type ImageBlockParamResp struct{…}`

        - `Source ImageBlockParamSourceUnionResp`

          - `type Base64ImageSource struct{…}`

            - `Data string`

            - `MediaType Base64ImageSourceMediaType`

              - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

              - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

              - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

              - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

            - `Type Base64`

              - `const Base64Base64 Base64 = "base64"`

          - `type URLImageSource struct{…}`

            - `Type URL`

              - `const URLURL URL = "url"`

            - `URL string`

        - `Type Image`

          - `const ImageImage Image = "image"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

      - `type SearchResultBlockParamResp struct{…}`

        - `Content []TextBlockParamResp`

          - `Text string`

          - `Type Text`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations []TextCitationParamUnionResp`

        - `Source string`

        - `Title string`

        - `Type SearchResult`

          - `const SearchResultSearchResult SearchResult = "search_result"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Citations CitationsConfigParamResp`

          - `Enabled bool`

      - `type DocumentBlockParamResp struct{…}`

        - `Source DocumentBlockParamSourceUnionResp`

          - `type Base64PDFSource struct{…}`

            - `Data string`

            - `MediaType ApplicationPDF`

              - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

            - `Type Base64`

              - `const Base64Base64 Base64 = "base64"`

          - `type PlainTextSource struct{…}`

            - `Data string`

            - `MediaType TextPlain`

              - `const TextPlainTextPlain TextPlain = "text/plain"`

            - `Type Text`

              - `const TextText Text = "text"`

          - `type ContentBlockSource struct{…}`

            - `Content ContentBlockSourceContentUnion`

              - `string`

              - `[]ContentBlockSourceContentItemUnion`

                - `type TextBlockParamResp struct{…}`

                - `type ImageBlockParamResp struct{…}`

            - `Type Content`

              - `const ContentContent Content = "content"`

          - `type URLPDFSource struct{…}`

            - `Type URL`

              - `const URLURL URL = "url"`

            - `URL string`

        - `Type Document`

          - `const DocumentDocument Document = "document"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Citations CitationsConfigParamResp`

        - `Context string`

        - `Title string`

      - `type ToolReferenceBlockParamResp struct{…}`

        Tool reference block that can be included in tool_result content.

        - `ToolName string`

        - `Type ToolReference`

          - `const ToolReferenceToolReference ToolReference = "tool_reference"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

  - `IsError bool`

### Tool Search Tool Bm25 20251119

- `type ToolSearchToolBm25_20251119 struct{…}`

  - `Name ToolSearchToolBm25`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const ToolSearchToolBm25ToolSearchToolBm25 ToolSearchToolBm25 = "tool_search_tool_bm25"`

  - `Type ToolSearchToolBm25_20251119Type`

    - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25_20251119 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25_20251119"`

    - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25"`

  - `AllowedCallers []string`

    - `const ToolSearchToolBm25_20251119AllowedCallerDirect ToolSearchToolBm25_20251119AllowedCaller = "direct"`

    - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20250825 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20250825"`

    - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20260120 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Tool Search Tool Regex 20251119

- `type ToolSearchToolRegex20251119 struct{…}`

  - `Name ToolSearchToolRegex`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const ToolSearchToolRegexToolSearchToolRegex ToolSearchToolRegex = "tool_search_tool_regex"`

  - `Type ToolSearchToolRegex20251119Type`

    - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex20251119 ToolSearchToolRegex20251119Type = "tool_search_tool_regex_20251119"`

    - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex ToolSearchToolRegex20251119Type = "tool_search_tool_regex"`

  - `AllowedCallers []string`

    - `const ToolSearchToolRegex20251119AllowedCallerDirect ToolSearchToolRegex20251119AllowedCaller = "direct"`

    - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20250825 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20250825"`

    - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20260120 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Tool Search Tool Result Block

- `type ToolSearchToolResultBlock struct{…}`

  - `Content ToolSearchToolResultBlockContentUnion`

    - `type ToolSearchToolResultError struct{…}`

      - `ErrorCode ToolSearchToolResultErrorCode`

        - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

        - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

        - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

        - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

      - `ErrorMessage string`

      - `Type ToolSearchToolResultError`

        - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

    - `type ToolSearchToolSearchResultBlock struct{…}`

      - `ToolReferences []ToolReferenceBlock`

        - `ToolName string`

        - `Type ToolReference`

          - `const ToolReferenceToolReference ToolReference = "tool_reference"`

      - `Type ToolSearchToolSearchResult`

        - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

  - `ToolUseID string`

  - `Type ToolSearchToolResult`

    - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

### Tool Search Tool Result Block Param

- `type ToolSearchToolResultBlockParamResp struct{…}`

  - `Content ToolSearchToolResultBlockParamContentUnionResp`

    - `type ToolSearchToolResultErrorParamResp struct{…}`

      - `ErrorCode ToolSearchToolResultErrorCode`

        - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

        - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

        - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

        - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

      - `Type ToolSearchToolResultError`

        - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

      - `ErrorMessage string`

    - `type ToolSearchToolSearchResultBlockParamResp struct{…}`

      - `ToolReferences []ToolReferenceBlockParamResp`

        - `ToolName string`

        - `Type ToolReference`

          - `const ToolReferenceToolReference ToolReference = "tool_reference"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

          - `Type Ephemeral`

            - `const EphemeralEphemeral Ephemeral = "ephemeral"`

          - `TTL CacheControlEphemeralTTL`

            The time-to-live for the cache control breakpoint.

            This may be one the following values:

            - `5m`: 5 minutes
            - `1h`: 1 hour

            Defaults to `5m`.

            - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

            - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

      - `Type ToolSearchToolSearchResult`

        - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

  - `ToolUseID string`

  - `Type ToolSearchToolResult`

    - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

### Tool Search Tool Result Error

- `type ToolSearchToolResultError struct{…}`

  - `ErrorCode ToolSearchToolResultErrorCode`

    - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

    - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

    - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

    - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

  - `ErrorMessage string`

  - `Type ToolSearchToolResultError`

    - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

### Tool Search Tool Result Error Code

- `type ToolSearchToolResultErrorCode string`

  - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

  - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

  - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

  - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

### Tool Search Tool Result Error Param

- `type ToolSearchToolResultErrorParamResp struct{…}`

  - `ErrorCode ToolSearchToolResultErrorCode`

    - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

    - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

    - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

    - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

  - `Type ToolSearchToolResultError`

    - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

  - `ErrorMessage string`

### Tool Search Tool Search Result Block

- `type ToolSearchToolSearchResultBlock struct{…}`

  - `ToolReferences []ToolReferenceBlock`

    - `ToolName string`

    - `Type ToolReference`

      - `const ToolReferenceToolReference ToolReference = "tool_reference"`

  - `Type ToolSearchToolSearchResult`

    - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

### Tool Search Tool Search Result Block Param

- `type ToolSearchToolSearchResultBlockParamResp struct{…}`

  - `ToolReferences []ToolReferenceBlockParamResp`

    - `ToolName string`

    - `Type ToolReference`

      - `const ToolReferenceToolReference ToolReference = "tool_reference"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

      - `Type Ephemeral`

        - `const EphemeralEphemeral Ephemeral = "ephemeral"`

      - `TTL CacheControlEphemeralTTL`

        The time-to-live for the cache control breakpoint.

        This may be one the following values:

        - `5m`: 5 minutes
        - `1h`: 1 hour

        Defaults to `5m`.

        - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

        - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `Type ToolSearchToolSearchResult`

    - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

### Tool Text Editor 20250124

- `type ToolTextEditor20250124 struct{…}`

  - `Name StrReplaceEditor`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const StrReplaceEditorStrReplaceEditor StrReplaceEditor = "str_replace_editor"`

  - `Type TextEditor20250124`

    - `const TextEditor20250124TextEditor20250124 TextEditor20250124 = "text_editor_20250124"`

  - `AllowedCallers []string`

    - `const ToolTextEditor20250124AllowedCallerDirect ToolTextEditor20250124AllowedCaller = "direct"`

    - `const ToolTextEditor20250124AllowedCallerCodeExecution20250825 ToolTextEditor20250124AllowedCaller = "code_execution_20250825"`

    - `const ToolTextEditor20250124AllowedCallerCodeExecution20260120 ToolTextEditor20250124AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `InputExamples []map[string, any]`

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Tool Text Editor 20250429

- `type ToolTextEditor20250429 struct{…}`

  - `Name StrReplaceBasedEditTool`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

  - `Type TextEditor20250429`

    - `const TextEditor20250429TextEditor20250429 TextEditor20250429 = "text_editor_20250429"`

  - `AllowedCallers []string`

    - `const ToolTextEditor20250429AllowedCallerDirect ToolTextEditor20250429AllowedCaller = "direct"`

    - `const ToolTextEditor20250429AllowedCallerCodeExecution20250825 ToolTextEditor20250429AllowedCaller = "code_execution_20250825"`

    - `const ToolTextEditor20250429AllowedCallerCodeExecution20260120 ToolTextEditor20250429AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `InputExamples []map[string, any]`

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Tool Text Editor 20250728

- `type ToolTextEditor20250728 struct{…}`

  - `Name StrReplaceBasedEditTool`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

  - `Type TextEditor20250728`

    - `const TextEditor20250728TextEditor20250728 TextEditor20250728 = "text_editor_20250728"`

  - `AllowedCallers []string`

    - `const ToolTextEditor20250728AllowedCallerDirect ToolTextEditor20250728AllowedCaller = "direct"`

    - `const ToolTextEditor20250728AllowedCallerCodeExecution20250825 ToolTextEditor20250728AllowedCaller = "code_execution_20250825"`

    - `const ToolTextEditor20250728AllowedCallerCodeExecution20260120 ToolTextEditor20250728AllowedCaller = "code_execution_20260120"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `InputExamples []map[string, any]`

  - `MaxCharacters int64`

    Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Tool Union

- `type ToolUnion interface{…}`

  Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

  - `type Tool struct{…}`

    - `InputSchema ToolInputSchema`

      [JSON schema](https://json-schema.org/draft/2020-12) for this tool's input.

      This defines the shape of the `input` that your tool accepts and that the model will produce.

      - `Type Object`

        - `const ObjectObject Object = "object"`

      - `Properties map[string, any]`

      - `Required []string`

    - `Name string`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

    - `AllowedCallers []string`

      - `const ToolAllowedCallerDirect ToolAllowedCaller = "direct"`

      - `const ToolAllowedCallerCodeExecution20250825 ToolAllowedCaller = "code_execution_20250825"`

      - `const ToolAllowedCallerCodeExecution20260120 ToolAllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

      - `Type Ephemeral`

        - `const EphemeralEphemeral Ephemeral = "ephemeral"`

      - `TTL CacheControlEphemeralTTL`

        The time-to-live for the cache control breakpoint.

        This may be one the following values:

        - `5m`: 5 minutes
        - `1h`: 1 hour

        Defaults to `5m`.

        - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

        - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Description string`

      Description of what this tool does.

      Tool descriptions should be as detailed as possible. The more information that the model has about what the tool is and how to use it, the better it will perform. You can use natural language descriptions to reinforce important aspects of the tool input JSON schema.

    - `EagerInputStreaming bool`

      Enable eager input streaming for this tool. When true, tool input parameters will be streamed incrementally as they are generated, and types will be inferred on-the-fly rather than buffering the full JSON output. When false, streaming is disabled for this tool even if the fine-grained-tool-streaming beta is active. When null (default), uses the default behavior based on beta headers.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

    - `Type ToolType`

      - `const ToolTypeCustom ToolType = "custom"`

  - `type ToolBash20250124 struct{…}`

    - `Name Bash`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const BashBash Bash = "bash"`

    - `Type Bash20250124`

      - `const Bash20250124Bash20250124 Bash20250124 = "bash_20250124"`

    - `AllowedCallers []string`

      - `const ToolBash20250124AllowedCallerDirect ToolBash20250124AllowedCaller = "direct"`

      - `const ToolBash20250124AllowedCallerCodeExecution20250825 ToolBash20250124AllowedCaller = "code_execution_20250825"`

      - `const ToolBash20250124AllowedCallerCodeExecution20260120 ToolBash20250124AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type CodeExecutionTool20250522 struct{…}`

    - `Name CodeExecution`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

    - `Type CodeExecution20250522`

      - `const CodeExecution20250522CodeExecution20250522 CodeExecution20250522 = "code_execution_20250522"`

    - `AllowedCallers []string`

      - `const CodeExecutionTool20250522AllowedCallerDirect CodeExecutionTool20250522AllowedCaller = "direct"`

      - `const CodeExecutionTool20250522AllowedCallerCodeExecution20250825 CodeExecutionTool20250522AllowedCaller = "code_execution_20250825"`

      - `const CodeExecutionTool20250522AllowedCallerCodeExecution20260120 CodeExecutionTool20250522AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type CodeExecutionTool20250825 struct{…}`

    - `Name CodeExecution`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

    - `Type CodeExecution20250825`

      - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `AllowedCallers []string`

      - `const CodeExecutionTool20250825AllowedCallerDirect CodeExecutionTool20250825AllowedCaller = "direct"`

      - `const CodeExecutionTool20250825AllowedCallerCodeExecution20250825 CodeExecutionTool20250825AllowedCaller = "code_execution_20250825"`

      - `const CodeExecutionTool20250825AllowedCallerCodeExecution20260120 CodeExecutionTool20250825AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type CodeExecutionTool20260120 struct{…}`

    Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

    - `Name CodeExecution`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

    - `Type CodeExecution20260120`

      - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

    - `AllowedCallers []string`

      - `const CodeExecutionTool20260120AllowedCallerDirect CodeExecutionTool20260120AllowedCaller = "direct"`

      - `const CodeExecutionTool20260120AllowedCallerCodeExecution20250825 CodeExecutionTool20260120AllowedCaller = "code_execution_20250825"`

      - `const CodeExecutionTool20260120AllowedCallerCodeExecution20260120 CodeExecutionTool20260120AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type MemoryTool20250818 struct{…}`

    - `Name Memory`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const MemoryMemory Memory = "memory"`

    - `Type Memory20250818`

      - `const Memory20250818Memory20250818 Memory20250818 = "memory_20250818"`

    - `AllowedCallers []string`

      - `const MemoryTool20250818AllowedCallerDirect MemoryTool20250818AllowedCaller = "direct"`

      - `const MemoryTool20250818AllowedCallerCodeExecution20250825 MemoryTool20250818AllowedCaller = "code_execution_20250825"`

      - `const MemoryTool20250818AllowedCallerCodeExecution20260120 MemoryTool20250818AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type ToolTextEditor20250124 struct{…}`

    - `Name StrReplaceEditor`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const StrReplaceEditorStrReplaceEditor StrReplaceEditor = "str_replace_editor"`

    - `Type TextEditor20250124`

      - `const TextEditor20250124TextEditor20250124 TextEditor20250124 = "text_editor_20250124"`

    - `AllowedCallers []string`

      - `const ToolTextEditor20250124AllowedCallerDirect ToolTextEditor20250124AllowedCaller = "direct"`

      - `const ToolTextEditor20250124AllowedCallerCodeExecution20250825 ToolTextEditor20250124AllowedCaller = "code_execution_20250825"`

      - `const ToolTextEditor20250124AllowedCallerCodeExecution20260120 ToolTextEditor20250124AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type ToolTextEditor20250429 struct{…}`

    - `Name StrReplaceBasedEditTool`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

    - `Type TextEditor20250429`

      - `const TextEditor20250429TextEditor20250429 TextEditor20250429 = "text_editor_20250429"`

    - `AllowedCallers []string`

      - `const ToolTextEditor20250429AllowedCallerDirect ToolTextEditor20250429AllowedCaller = "direct"`

      - `const ToolTextEditor20250429AllowedCallerCodeExecution20250825 ToolTextEditor20250429AllowedCaller = "code_execution_20250825"`

      - `const ToolTextEditor20250429AllowedCallerCodeExecution20260120 ToolTextEditor20250429AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type ToolTextEditor20250728 struct{…}`

    - `Name StrReplaceBasedEditTool`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

    - `Type TextEditor20250728`

      - `const TextEditor20250728TextEditor20250728 TextEditor20250728 = "text_editor_20250728"`

    - `AllowedCallers []string`

      - `const ToolTextEditor20250728AllowedCallerDirect ToolTextEditor20250728AllowedCaller = "direct"`

      - `const ToolTextEditor20250728AllowedCallerCodeExecution20250825 ToolTextEditor20250728AllowedCaller = "code_execution_20250825"`

      - `const ToolTextEditor20250728AllowedCallerCodeExecution20260120 ToolTextEditor20250728AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `InputExamples []map[string, any]`

    - `MaxCharacters int64`

      Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type WebSearchTool20250305 struct{…}`

    - `Name WebSearch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebSearchWebSearch WebSearch = "web_search"`

    - `Type WebSearch20250305`

      - `const WebSearch20250305WebSearch20250305 WebSearch20250305 = "web_search_20250305"`

    - `AllowedCallers []string`

      - `const WebSearchTool20250305AllowedCallerDirect WebSearchTool20250305AllowedCaller = "direct"`

      - `const WebSearchTool20250305AllowedCallerCodeExecution20250825 WebSearchTool20250305AllowedCaller = "code_execution_20250825"`

      - `const WebSearchTool20250305AllowedCallerCodeExecution20260120 WebSearchTool20250305AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

    - `BlockedDomains []string`

      If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

    - `UserLocation UserLocation`

      Parameters for the user's location. Used to provide more relevant search results.

      - `Type Approximate`

        - `const ApproximateApproximate Approximate = "approximate"`

      - `City string`

        The city of the user.

      - `Country string`

        The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user.

      - `Region string`

        The region of the user.

      - `Timezone string`

        The [IANA timezone](https://nodatime.org/TimeZones) of the user.

  - `type WebFetchTool20250910 struct{…}`

    - `Name WebFetch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebFetchWebFetch WebFetch = "web_fetch"`

    - `Type WebFetch20250910`

      - `const WebFetch20250910WebFetch20250910 WebFetch20250910 = "web_fetch_20250910"`

    - `AllowedCallers []string`

      - `const WebFetchTool20250910AllowedCallerDirect WebFetchTool20250910AllowedCaller = "direct"`

      - `const WebFetchTool20250910AllowedCallerCodeExecution20250825 WebFetchTool20250910AllowedCaller = "code_execution_20250825"`

      - `const WebFetchTool20250910AllowedCallerCodeExecution20260120 WebFetchTool20250910AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      List of domains to allow fetching from

    - `BlockedDomains []string`

      List of domains to block fetching from

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Citations CitationsConfigParamResp`

      Citations configuration for fetched documents. Citations are disabled by default.

      - `Enabled bool`

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxContentTokens int64`

      Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type WebSearchTool20260209 struct{…}`

    - `Name WebSearch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebSearchWebSearch WebSearch = "web_search"`

    - `Type WebSearch20260209`

      - `const WebSearch20260209WebSearch20260209 WebSearch20260209 = "web_search_20260209"`

    - `AllowedCallers []string`

      - `const WebSearchTool20260209AllowedCallerDirect WebSearchTool20260209AllowedCaller = "direct"`

      - `const WebSearchTool20260209AllowedCallerCodeExecution20250825 WebSearchTool20260209AllowedCaller = "code_execution_20250825"`

      - `const WebSearchTool20260209AllowedCallerCodeExecution20260120 WebSearchTool20260209AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

    - `BlockedDomains []string`

      If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

    - `UserLocation UserLocation`

      Parameters for the user's location. Used to provide more relevant search results.

  - `type WebFetchTool20260209 struct{…}`

    - `Name WebFetch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebFetchWebFetch WebFetch = "web_fetch"`

    - `Type WebFetch20260209`

      - `const WebFetch20260209WebFetch20260209 WebFetch20260209 = "web_fetch_20260209"`

    - `AllowedCallers []string`

      - `const WebFetchTool20260209AllowedCallerDirect WebFetchTool20260209AllowedCaller = "direct"`

      - `const WebFetchTool20260209AllowedCallerCodeExecution20250825 WebFetchTool20260209AllowedCaller = "code_execution_20250825"`

      - `const WebFetchTool20260209AllowedCallerCodeExecution20260120 WebFetchTool20260209AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      List of domains to allow fetching from

    - `BlockedDomains []string`

      List of domains to block fetching from

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Citations CitationsConfigParamResp`

      Citations configuration for fetched documents. Citations are disabled by default.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxContentTokens int64`

      Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type WebFetchTool20260309 struct{…}`

    Web fetch tool with use_cache parameter for bypassing cached content.

    - `Name WebFetch`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const WebFetchWebFetch WebFetch = "web_fetch"`

    - `Type WebFetch20260309`

      - `const WebFetch20260309WebFetch20260309 WebFetch20260309 = "web_fetch_20260309"`

    - `AllowedCallers []string`

      - `const WebFetchTool20260309AllowedCallerDirect WebFetchTool20260309AllowedCaller = "direct"`

      - `const WebFetchTool20260309AllowedCallerCodeExecution20250825 WebFetchTool20260309AllowedCaller = "code_execution_20250825"`

      - `const WebFetchTool20260309AllowedCallerCodeExecution20260120 WebFetchTool20260309AllowedCaller = "code_execution_20260120"`

    - `AllowedDomains []string`

      List of domains to allow fetching from

    - `BlockedDomains []string`

      List of domains to block fetching from

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Citations CitationsConfigParamResp`

      Citations configuration for fetched documents. Citations are disabled by default.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `MaxContentTokens int64`

      Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

    - `MaxUses int64`

      Maximum number of times the tool can be used in the API request.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

    - `UseCache bool`

      Whether to use cached content. Set to false to bypass the cache and fetch fresh content. Only set to false when the user explicitly requests fresh content or when fetching rapidly-changing sources.

  - `type ToolSearchToolBm25_20251119 struct{…}`

    - `Name ToolSearchToolBm25`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const ToolSearchToolBm25ToolSearchToolBm25 ToolSearchToolBm25 = "tool_search_tool_bm25"`

    - `Type ToolSearchToolBm25_20251119Type`

      - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25_20251119 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25_20251119"`

      - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25"`

    - `AllowedCallers []string`

      - `const ToolSearchToolBm25_20251119AllowedCallerDirect ToolSearchToolBm25_20251119AllowedCaller = "direct"`

      - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20250825 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20250825"`

      - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20260120 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

  - `type ToolSearchToolRegex20251119 struct{…}`

    - `Name ToolSearchToolRegex`

      Name of the tool.

      This is how the tool will be called by the model and in `tool_use` blocks.

      - `const ToolSearchToolRegexToolSearchToolRegex ToolSearchToolRegex = "tool_search_tool_regex"`

    - `Type ToolSearchToolRegex20251119Type`

      - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex20251119 ToolSearchToolRegex20251119Type = "tool_search_tool_regex_20251119"`

      - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex ToolSearchToolRegex20251119Type = "tool_search_tool_regex"`

    - `AllowedCallers []string`

      - `const ToolSearchToolRegex20251119AllowedCallerDirect ToolSearchToolRegex20251119AllowedCaller = "direct"`

      - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20250825 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20250825"`

      - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20260120 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20260120"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `DeferLoading bool`

      If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

    - `Strict bool`

      When true, guarantees schema validation on tool names and inputs

### Tool Use Block

- `type ToolUseBlock struct{…}`

  - `ID string`

  - `Caller ToolUseBlockCallerUnion`

    Tool invocation directly from the model.

    - `type DirectCaller struct{…}`

      Tool invocation directly from the model.

      - `Type Direct`

        - `const DirectDirect Direct = "direct"`

    - `type ServerToolCaller struct{…}`

      Tool invocation generated by a server-side tool.

      - `ToolID string`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `type ServerToolCaller20260120 struct{…}`

      - `ToolID string`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

  - `Input map[string, any]`

  - `Name string`

  - `Type ToolUse`

    - `const ToolUseToolUse ToolUse = "tool_use"`

### Tool Use Block Param

- `type ToolUseBlockParamResp struct{…}`

  - `ID string`

  - `Input map[string, any]`

  - `Name string`

  - `Type ToolUse`

    - `const ToolUseToolUse ToolUse = "tool_use"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `Caller ToolUseBlockParamCallerUnionResp`

    Tool invocation directly from the model.

    - `type DirectCaller struct{…}`

      Tool invocation directly from the model.

      - `Type Direct`

        - `const DirectDirect Direct = "direct"`

    - `type ServerToolCaller struct{…}`

      Tool invocation generated by a server-side tool.

      - `ToolID string`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `type ServerToolCaller20260120 struct{…}`

      - `ToolID string`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

### URL Image Source

- `type URLImageSource struct{…}`

  - `Type URL`

    - `const URLURL URL = "url"`

  - `URL string`

### URL PDF Source

- `type URLPDFSource struct{…}`

  - `Type URL`

    - `const URLURL URL = "url"`

  - `URL string`

### Usage

- `type Usage struct{…}`

  - `CacheCreation CacheCreation`

    Breakdown of cached tokens by TTL

    - `Ephemeral1hInputTokens int64`

      The number of input tokens used to create the 1 hour cache entry.

    - `Ephemeral5mInputTokens int64`

      The number of input tokens used to create the 5 minute cache entry.

  - `CacheCreationInputTokens int64`

    The number of input tokens used to create the cache entry.

  - `CacheReadInputTokens int64`

    The number of input tokens read from the cache.

  - `InferenceGeo string`

    The geographic region where inference was performed for this request.

  - `InputTokens int64`

    The number of input tokens which were used.

  - `OutputTokens int64`

    The number of output tokens which were used.

  - `OutputTokensDetails OutputTokensDetails`

    Breakdown of output tokens by category.

    `output_tokens` remains the inclusive, authoritative total used for billing.
    This object provides a read-only decomposition for observability — for example,
    how many of the billed output tokens were spent on internal reasoning that may
    have been summarized before being returned to you.

    - `ThinkingTokens int64`

      Number of output tokens the model generated as internal reasoning, including
      the thinking-block delimiter tokens.

      Reflects the raw reasoning the model produced, not the (possibly shorter)
      summarized thinking text returned in the response body. Computed by
      re-tokenizing the raw reasoning text, so it may differ from the model's exact
      generation count by a small number of tokens. Always ≤ `output_tokens`;
      `output_tokens - thinking_tokens` approximates the non-reasoning output.

  - `ServerToolUse ServerToolUsage`

    The number of server tool requests.

    - `WebFetchRequests int64`

      The number of web fetch tool requests.

    - `WebSearchRequests int64`

      The number of web search tool requests.

  - `ServiceTier UsageServiceTier`

    If the request used the priority, standard, or batch tier.

    - `const UsageServiceTierStandard UsageServiceTier = "standard"`

    - `const UsageServiceTierPriority UsageServiceTier = "priority"`

    - `const UsageServiceTierBatch UsageServiceTier = "batch"`

### User Location

- `type UserLocation struct{…}`

  - `Type Approximate`

    - `const ApproximateApproximate Approximate = "approximate"`

  - `City string`

    The city of the user.

  - `Country string`

    The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user.

  - `Region string`

    The region of the user.

  - `Timezone string`

    The [IANA timezone](https://nodatime.org/TimeZones) of the user.

### Web Fetch Block

- `type WebFetchBlock struct{…}`

  - `Content DocumentBlock`

    - `Citations CitationsConfig`

      Citation configuration for the document

      - `Enabled bool`

    - `Source DocumentBlockSourceUnion`

      - `type Base64PDFSource struct{…}`

        - `Data string`

        - `MediaType ApplicationPDF`

          - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

        - `Type Base64`

          - `const Base64Base64 Base64 = "base64"`

      - `type PlainTextSource struct{…}`

        - `Data string`

        - `MediaType TextPlain`

          - `const TextPlainTextPlain TextPlain = "text/plain"`

        - `Type Text`

          - `const TextText Text = "text"`

    - `Title string`

      The title of the document

    - `Type Document`

      - `const DocumentDocument Document = "document"`

  - `RetrievedAt string`

    ISO 8601 timestamp when the content was retrieved

  - `Type WebFetchResult`

    - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

  - `URL string`

    Fetched content URL

### Web Fetch Block Param

- `type WebFetchBlockParamResp struct{…}`

  - `Content DocumentBlockParamResp`

    - `Source DocumentBlockParamSourceUnionResp`

      - `type Base64PDFSource struct{…}`

        - `Data string`

        - `MediaType ApplicationPDF`

          - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

        - `Type Base64`

          - `const Base64Base64 Base64 = "base64"`

      - `type PlainTextSource struct{…}`

        - `Data string`

        - `MediaType TextPlain`

          - `const TextPlainTextPlain TextPlain = "text/plain"`

        - `Type Text`

          - `const TextText Text = "text"`

      - `type ContentBlockSource struct{…}`

        - `Content ContentBlockSourceContentUnion`

          - `string`

          - `[]ContentBlockSourceContentItemUnion`

            - `type TextBlockParamResp struct{…}`

              - `Text string`

              - `Type Text`

                - `const TextText Text = "text"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

                - `Type Ephemeral`

                  - `const EphemeralEphemeral Ephemeral = "ephemeral"`

                - `TTL CacheControlEphemeralTTL`

                  The time-to-live for the cache control breakpoint.

                  This may be one the following values:

                  - `5m`: 5 minutes
                  - `1h`: 1 hour

                  Defaults to `5m`.

                  - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

                  - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

              - `Citations []TextCitationParamUnionResp`

                - `type CitationCharLocationParamResp struct{…}`

                  - `CitedText string`

                  - `DocumentIndex int64`

                  - `DocumentTitle string`

                  - `EndCharIndex int64`

                  - `StartCharIndex int64`

                  - `Type CharLocation`

                    - `const CharLocationCharLocation CharLocation = "char_location"`

                - `type CitationPageLocationParamResp struct{…}`

                  - `CitedText string`

                  - `DocumentIndex int64`

                  - `DocumentTitle string`

                  - `EndPageNumber int64`

                  - `StartPageNumber int64`

                  - `Type PageLocation`

                    - `const PageLocationPageLocation PageLocation = "page_location"`

                - `type CitationContentBlockLocationParamResp struct{…}`

                  - `CitedText string`

                    The full text of the cited block range, concatenated.

                    Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                  - `DocumentIndex int64`

                  - `DocumentTitle string`

                  - `EndBlockIndex int64`

                    Exclusive 0-based end index of the cited block range in the source's `content` array.

                    Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                  - `StartBlockIndex int64`

                    0-based index of the first cited block in the source's `content` array.

                  - `Type ContentBlockLocation`

                    - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

                - `type CitationWebSearchResultLocationParamResp struct{…}`

                  - `CitedText string`

                  - `EncryptedIndex string`

                  - `Title string`

                  - `Type WebSearchResultLocation`

                    - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

                  - `URL string`

                - `type CitationSearchResultLocationParamResp struct{…}`

                  - `CitedText string`

                    The full text of the cited block range, concatenated.

                    Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                  - `EndBlockIndex int64`

                    Exclusive 0-based end index of the cited block range in the source's `content` array.

                    Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                  - `SearchResultIndex int64`

                    0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                    Counted separately from `document_index`; server-side web search results are not included in this count.

                  - `Source string`

                  - `StartBlockIndex int64`

                    0-based index of the first cited block in the source's `content` array.

                  - `Title string`

                  - `Type SearchResultLocation`

                    - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

            - `type ImageBlockParamResp struct{…}`

              - `Source ImageBlockParamSourceUnionResp`

                - `type Base64ImageSource struct{…}`

                  - `Data string`

                  - `MediaType Base64ImageSourceMediaType`

                    - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

                    - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

                    - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

                    - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

                  - `Type Base64`

                    - `const Base64Base64 Base64 = "base64"`

                - `type URLImageSource struct{…}`

                  - `Type URL`

                    - `const URLURL URL = "url"`

                  - `URL string`

              - `Type Image`

                - `const ImageImage Image = "image"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

        - `Type Content`

          - `const ContentContent Content = "content"`

      - `type URLPDFSource struct{…}`

        - `Type URL`

          - `const URLURL URL = "url"`

        - `URL string`

    - `Type Document`

      - `const DocumentDocument Document = "document"`

    - `CacheControl CacheControlEphemeral`

      Create a cache control breakpoint at this content block.

    - `Citations CitationsConfigParamResp`

      - `Enabled bool`

    - `Context string`

    - `Title string`

  - `Type WebFetchResult`

    - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

  - `URL string`

    Fetched content URL

  - `RetrievedAt string`

    ISO 8601 timestamp when the content was retrieved

### Web Fetch Tool 20250910

- `type WebFetchTool20250910 struct{…}`

  - `Name WebFetch`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const WebFetchWebFetch WebFetch = "web_fetch"`

  - `Type WebFetch20250910`

    - `const WebFetch20250910WebFetch20250910 WebFetch20250910 = "web_fetch_20250910"`

  - `AllowedCallers []string`

    - `const WebFetchTool20250910AllowedCallerDirect WebFetchTool20250910AllowedCaller = "direct"`

    - `const WebFetchTool20250910AllowedCallerCodeExecution20250825 WebFetchTool20250910AllowedCaller = "code_execution_20250825"`

    - `const WebFetchTool20250910AllowedCallerCodeExecution20260120 WebFetchTool20250910AllowedCaller = "code_execution_20260120"`

  - `AllowedDomains []string`

    List of domains to allow fetching from

  - `BlockedDomains []string`

    List of domains to block fetching from

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `Citations CitationsConfigParamResp`

    Citations configuration for fetched documents. Citations are disabled by default.

    - `Enabled bool`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `MaxContentTokens int64`

    Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

  - `MaxUses int64`

    Maximum number of times the tool can be used in the API request.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Web Fetch Tool 20260209

- `type WebFetchTool20260209 struct{…}`

  - `Name WebFetch`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const WebFetchWebFetch WebFetch = "web_fetch"`

  - `Type WebFetch20260209`

    - `const WebFetch20260209WebFetch20260209 WebFetch20260209 = "web_fetch_20260209"`

  - `AllowedCallers []string`

    - `const WebFetchTool20260209AllowedCallerDirect WebFetchTool20260209AllowedCaller = "direct"`

    - `const WebFetchTool20260209AllowedCallerCodeExecution20250825 WebFetchTool20260209AllowedCaller = "code_execution_20250825"`

    - `const WebFetchTool20260209AllowedCallerCodeExecution20260120 WebFetchTool20260209AllowedCaller = "code_execution_20260120"`

  - `AllowedDomains []string`

    List of domains to allow fetching from

  - `BlockedDomains []string`

    List of domains to block fetching from

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `Citations CitationsConfigParamResp`

    Citations configuration for fetched documents. Citations are disabled by default.

    - `Enabled bool`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `MaxContentTokens int64`

    Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

  - `MaxUses int64`

    Maximum number of times the tool can be used in the API request.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

### Web Fetch Tool 20260309

- `type WebFetchTool20260309 struct{…}`

  Web fetch tool with use_cache parameter for bypassing cached content.

  - `Name WebFetch`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const WebFetchWebFetch WebFetch = "web_fetch"`

  - `Type WebFetch20260309`

    - `const WebFetch20260309WebFetch20260309 WebFetch20260309 = "web_fetch_20260309"`

  - `AllowedCallers []string`

    - `const WebFetchTool20260309AllowedCallerDirect WebFetchTool20260309AllowedCaller = "direct"`

    - `const WebFetchTool20260309AllowedCallerCodeExecution20250825 WebFetchTool20260309AllowedCaller = "code_execution_20250825"`

    - `const WebFetchTool20260309AllowedCallerCodeExecution20260120 WebFetchTool20260309AllowedCaller = "code_execution_20260120"`

  - `AllowedDomains []string`

    List of domains to allow fetching from

  - `BlockedDomains []string`

    List of domains to block fetching from

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `Citations CitationsConfigParamResp`

    Citations configuration for fetched documents. Citations are disabled by default.

    - `Enabled bool`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `MaxContentTokens int64`

    Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

  - `MaxUses int64`

    Maximum number of times the tool can be used in the API request.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

  - `UseCache bool`

    Whether to use cached content. Set to false to bypass the cache and fetch fresh content. Only set to false when the user explicitly requests fresh content or when fetching rapidly-changing sources.

### Web Fetch Tool Result Block

- `type WebFetchToolResultBlock struct{…}`

  - `Caller WebFetchToolResultBlockCallerUnion`

    Tool invocation directly from the model.

    - `type DirectCaller struct{…}`

      Tool invocation directly from the model.

      - `Type Direct`

        - `const DirectDirect Direct = "direct"`

    - `type ServerToolCaller struct{…}`

      Tool invocation generated by a server-side tool.

      - `ToolID string`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `type ServerToolCaller20260120 struct{…}`

      - `ToolID string`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

  - `Content WebFetchToolResultBlockContentUnion`

    - `type WebFetchToolResultErrorBlock struct{…}`

      - `ErrorCode WebFetchToolResultErrorCode`

        - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

        - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

        - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

        - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

        - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

        - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

        - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

        - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

        - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

      - `Type WebFetchToolResultError`

        - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

    - `type WebFetchBlock struct{…}`

      - `Content DocumentBlock`

        - `Citations CitationsConfig`

          Citation configuration for the document

          - `Enabled bool`

        - `Source DocumentBlockSourceUnion`

          - `type Base64PDFSource struct{…}`

            - `Data string`

            - `MediaType ApplicationPDF`

              - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

            - `Type Base64`

              - `const Base64Base64 Base64 = "base64"`

          - `type PlainTextSource struct{…}`

            - `Data string`

            - `MediaType TextPlain`

              - `const TextPlainTextPlain TextPlain = "text/plain"`

            - `Type Text`

              - `const TextText Text = "text"`

        - `Title string`

          The title of the document

        - `Type Document`

          - `const DocumentDocument Document = "document"`

      - `RetrievedAt string`

        ISO 8601 timestamp when the content was retrieved

      - `Type WebFetchResult`

        - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

      - `URL string`

        Fetched content URL

  - `ToolUseID string`

  - `Type WebFetchToolResult`

    - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

### Web Fetch Tool Result Block Param

- `type WebFetchToolResultBlockParamResp struct{…}`

  - `Content WebFetchToolResultBlockParamContentUnionResp`

    - `type WebFetchToolResultErrorBlockParamResp struct{…}`

      - `ErrorCode WebFetchToolResultErrorCode`

        - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

        - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

        - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

        - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

        - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

        - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

        - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

        - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

        - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

      - `Type WebFetchToolResultError`

        - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

    - `type WebFetchBlockParamResp struct{…}`

      - `Content DocumentBlockParamResp`

        - `Source DocumentBlockParamSourceUnionResp`

          - `type Base64PDFSource struct{…}`

            - `Data string`

            - `MediaType ApplicationPDF`

              - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

            - `Type Base64`

              - `const Base64Base64 Base64 = "base64"`

          - `type PlainTextSource struct{…}`

            - `Data string`

            - `MediaType TextPlain`

              - `const TextPlainTextPlain TextPlain = "text/plain"`

            - `Type Text`

              - `const TextText Text = "text"`

          - `type ContentBlockSource struct{…}`

            - `Content ContentBlockSourceContentUnion`

              - `string`

              - `[]ContentBlockSourceContentItemUnion`

                - `type TextBlockParamResp struct{…}`

                  - `Text string`

                  - `Type Text`

                    - `const TextText Text = "text"`

                  - `CacheControl CacheControlEphemeral`

                    Create a cache control breakpoint at this content block.

                    - `Type Ephemeral`

                      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

                    - `TTL CacheControlEphemeralTTL`

                      The time-to-live for the cache control breakpoint.

                      This may be one the following values:

                      - `5m`: 5 minutes
                      - `1h`: 1 hour

                      Defaults to `5m`.

                      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

                      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

                  - `Citations []TextCitationParamUnionResp`

                    - `type CitationCharLocationParamResp struct{…}`

                      - `CitedText string`

                      - `DocumentIndex int64`

                      - `DocumentTitle string`

                      - `EndCharIndex int64`

                      - `StartCharIndex int64`

                      - `Type CharLocation`

                        - `const CharLocationCharLocation CharLocation = "char_location"`

                    - `type CitationPageLocationParamResp struct{…}`

                      - `CitedText string`

                      - `DocumentIndex int64`

                      - `DocumentTitle string`

                      - `EndPageNumber int64`

                      - `StartPageNumber int64`

                      - `Type PageLocation`

                        - `const PageLocationPageLocation PageLocation = "page_location"`

                    - `type CitationContentBlockLocationParamResp struct{…}`

                      - `CitedText string`

                        The full text of the cited block range, concatenated.

                        Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                      - `DocumentIndex int64`

                      - `DocumentTitle string`

                      - `EndBlockIndex int64`

                        Exclusive 0-based end index of the cited block range in the source's `content` array.

                        Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                      - `StartBlockIndex int64`

                        0-based index of the first cited block in the source's `content` array.

                      - `Type ContentBlockLocation`

                        - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

                    - `type CitationWebSearchResultLocationParamResp struct{…}`

                      - `CitedText string`

                      - `EncryptedIndex string`

                      - `Title string`

                      - `Type WebSearchResultLocation`

                        - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

                      - `URL string`

                    - `type CitationSearchResultLocationParamResp struct{…}`

                      - `CitedText string`

                        The full text of the cited block range, concatenated.

                        Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                      - `EndBlockIndex int64`

                        Exclusive 0-based end index of the cited block range in the source's `content` array.

                        Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                      - `SearchResultIndex int64`

                        0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                        Counted separately from `document_index`; server-side web search results are not included in this count.

                      - `Source string`

                      - `StartBlockIndex int64`

                        0-based index of the first cited block in the source's `content` array.

                      - `Title string`

                      - `Type SearchResultLocation`

                        - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

                - `type ImageBlockParamResp struct{…}`

                  - `Source ImageBlockParamSourceUnionResp`

                    - `type Base64ImageSource struct{…}`

                      - `Data string`

                      - `MediaType Base64ImageSourceMediaType`

                        - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

                        - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

                        - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

                        - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

                      - `Type Base64`

                        - `const Base64Base64 Base64 = "base64"`

                    - `type URLImageSource struct{…}`

                      - `Type URL`

                        - `const URLURL URL = "url"`

                      - `URL string`

                  - `Type Image`

                    - `const ImageImage Image = "image"`

                  - `CacheControl CacheControlEphemeral`

                    Create a cache control breakpoint at this content block.

            - `Type Content`

              - `const ContentContent Content = "content"`

          - `type URLPDFSource struct{…}`

            - `Type URL`

              - `const URLURL URL = "url"`

            - `URL string`

        - `Type Document`

          - `const DocumentDocument Document = "document"`

        - `CacheControl CacheControlEphemeral`

          Create a cache control breakpoint at this content block.

        - `Citations CitationsConfigParamResp`

          - `Enabled bool`

        - `Context string`

        - `Title string`

      - `Type WebFetchResult`

        - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

      - `URL string`

        Fetched content URL

      - `RetrievedAt string`

        ISO 8601 timestamp when the content was retrieved

  - `ToolUseID string`

  - `Type WebFetchToolResult`

    - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

  - `Caller WebFetchToolResultBlockParamCallerUnionResp`

    Tool invocation directly from the model.

    - `type DirectCaller struct{…}`

      Tool invocation directly from the model.

      - `Type Direct`

        - `const DirectDirect Direct = "direct"`

    - `type ServerToolCaller struct{…}`

      Tool invocation generated by a server-side tool.

      - `ToolID string`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `type ServerToolCaller20260120 struct{…}`

      - `ToolID string`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

### Web Fetch Tool Result Error Block

- `type WebFetchToolResultErrorBlock struct{…}`

  - `ErrorCode WebFetchToolResultErrorCode`

    - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

    - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

    - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

    - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

    - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

    - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

    - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

    - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

    - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

  - `Type WebFetchToolResultError`

    - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

### Web Fetch Tool Result Error Block Param

- `type WebFetchToolResultErrorBlockParamResp struct{…}`

  - `ErrorCode WebFetchToolResultErrorCode`

    - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

    - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

    - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

    - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

    - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

    - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

    - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

    - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

    - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

  - `Type WebFetchToolResultError`

    - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

### Web Fetch Tool Result Error Code

- `type WebFetchToolResultErrorCode string`

  - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

  - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

  - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

  - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

  - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

  - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

  - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

  - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

  - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

### Web Search Result Block

- `type WebSearchResultBlock struct{…}`

  - `EncryptedContent string`

  - `PageAge string`

  - `Title string`

  - `Type WebSearchResult`

    - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

  - `URL string`

### Web Search Result Block Param

- `type WebSearchResultBlockParamResp struct{…}`

  - `EncryptedContent string`

  - `Title string`

  - `Type WebSearchResult`

    - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

  - `URL string`

  - `PageAge string`

### Web Search Tool 20250305

- `type WebSearchTool20250305 struct{…}`

  - `Name WebSearch`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const WebSearchWebSearch WebSearch = "web_search"`

  - `Type WebSearch20250305`

    - `const WebSearch20250305WebSearch20250305 WebSearch20250305 = "web_search_20250305"`

  - `AllowedCallers []string`

    - `const WebSearchTool20250305AllowedCallerDirect WebSearchTool20250305AllowedCaller = "direct"`

    - `const WebSearchTool20250305AllowedCallerCodeExecution20250825 WebSearchTool20250305AllowedCaller = "code_execution_20250825"`

    - `const WebSearchTool20250305AllowedCallerCodeExecution20260120 WebSearchTool20250305AllowedCaller = "code_execution_20260120"`

  - `AllowedDomains []string`

    If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

  - `BlockedDomains []string`

    If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `MaxUses int64`

    Maximum number of times the tool can be used in the API request.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

  - `UserLocation UserLocation`

    Parameters for the user's location. Used to provide more relevant search results.

    - `Type Approximate`

      - `const ApproximateApproximate Approximate = "approximate"`

    - `City string`

      The city of the user.

    - `Country string`

      The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user.

    - `Region string`

      The region of the user.

    - `Timezone string`

      The [IANA timezone](https://nodatime.org/TimeZones) of the user.

### Web Search Tool 20260209

- `type WebSearchTool20260209 struct{…}`

  - `Name WebSearch`

    Name of the tool.

    This is how the tool will be called by the model and in `tool_use` blocks.

    - `const WebSearchWebSearch WebSearch = "web_search"`

  - `Type WebSearch20260209`

    - `const WebSearch20260209WebSearch20260209 WebSearch20260209 = "web_search_20260209"`

  - `AllowedCallers []string`

    - `const WebSearchTool20260209AllowedCallerDirect WebSearchTool20260209AllowedCaller = "direct"`

    - `const WebSearchTool20260209AllowedCallerCodeExecution20250825 WebSearchTool20260209AllowedCaller = "code_execution_20250825"`

    - `const WebSearchTool20260209AllowedCallerCodeExecution20260120 WebSearchTool20260209AllowedCaller = "code_execution_20260120"`

  - `AllowedDomains []string`

    If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

  - `BlockedDomains []string`

    If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `DeferLoading bool`

    If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

  - `MaxUses int64`

    Maximum number of times the tool can be used in the API request.

  - `Strict bool`

    When true, guarantees schema validation on tool names and inputs

  - `UserLocation UserLocation`

    Parameters for the user's location. Used to provide more relevant search results.

    - `Type Approximate`

      - `const ApproximateApproximate Approximate = "approximate"`

    - `City string`

      The city of the user.

    - `Country string`

      The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user.

    - `Region string`

      The region of the user.

    - `Timezone string`

      The [IANA timezone](https://nodatime.org/TimeZones) of the user.

### Web Search Tool Request Error

- `type WebSearchToolRequestError struct{…}`

  - `ErrorCode WebSearchToolResultErrorCode`

    - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

    - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

    - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

    - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

    - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

    - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

  - `Type WebSearchToolResultError`

    - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

### Web Search Tool Result Block

- `type WebSearchToolResultBlock struct{…}`

  - `Caller WebSearchToolResultBlockCallerUnion`

    Tool invocation directly from the model.

    - `type DirectCaller struct{…}`

      Tool invocation directly from the model.

      - `Type Direct`

        - `const DirectDirect Direct = "direct"`

    - `type ServerToolCaller struct{…}`

      Tool invocation generated by a server-side tool.

      - `ToolID string`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `type ServerToolCaller20260120 struct{…}`

      - `ToolID string`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

  - `Content WebSearchToolResultBlockContentUnion`

    - `type WebSearchToolResultError struct{…}`

      - `ErrorCode WebSearchToolResultErrorCode`

        - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

        - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

        - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

        - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

        - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

        - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

      - `Type WebSearchToolResultError`

        - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

    - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

      - `EncryptedContent string`

      - `PageAge string`

      - `Title string`

      - `Type WebSearchResult`

        - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

      - `URL string`

  - `ToolUseID string`

  - `Type WebSearchToolResult`

    - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

### Web Search Tool Result Block Content

- `type WebSearchToolResultBlockContentUnion interface{…}`

  - `type WebSearchToolResultError struct{…}`

    - `ErrorCode WebSearchToolResultErrorCode`

      - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

      - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

      - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

      - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

      - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

      - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

    - `Type WebSearchToolResultError`

      - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

  - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

    - `EncryptedContent string`

    - `PageAge string`

    - `Title string`

    - `Type WebSearchResult`

      - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

    - `URL string`

### Web Search Tool Result Block Param

- `type WebSearchToolResultBlockParamResp struct{…}`

  - `Content WebSearchToolResultBlockParamContentUnionResp`

    - `[]WebSearchResultBlockParamResp`

      - `EncryptedContent string`

      - `Title string`

      - `Type WebSearchResult`

        - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

      - `URL string`

      - `PageAge string`

    - `type WebSearchToolRequestError struct{…}`

      - `ErrorCode WebSearchToolResultErrorCode`

        - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

        - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

        - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

        - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

        - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

        - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

      - `Type WebSearchToolResultError`

        - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

  - `ToolUseID string`

  - `Type WebSearchToolResult`

    - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

  - `CacheControl CacheControlEphemeral`

    Create a cache control breakpoint at this content block.

    - `Type Ephemeral`

      - `const EphemeralEphemeral Ephemeral = "ephemeral"`

    - `TTL CacheControlEphemeralTTL`

      The time-to-live for the cache control breakpoint.

      This may be one the following values:

      - `5m`: 5 minutes
      - `1h`: 1 hour

      Defaults to `5m`.

      - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

      - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

  - `Caller WebSearchToolResultBlockParamCallerUnionResp`

    Tool invocation directly from the model.

    - `type DirectCaller struct{…}`

      Tool invocation directly from the model.

      - `Type Direct`

        - `const DirectDirect Direct = "direct"`

    - `type ServerToolCaller struct{…}`

      Tool invocation generated by a server-side tool.

      - `ToolID string`

      - `Type CodeExecution20250825`

        - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

    - `type ServerToolCaller20260120 struct{…}`

      - `ToolID string`

      - `Type CodeExecution20260120`

        - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

### Web Search Tool Result Block Param Content

- `type WebSearchToolResultBlockParamContentUnionResp interface{…}`

  - `[]WebSearchResultBlockParamResp`

    - `EncryptedContent string`

    - `Title string`

    - `Type WebSearchResult`

      - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

    - `URL string`

    - `PageAge string`

  - `type WebSearchToolRequestError struct{…}`

    - `ErrorCode WebSearchToolResultErrorCode`

      - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

      - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

      - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

      - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

      - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

      - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

    - `Type WebSearchToolResultError`

      - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

### Web Search Tool Result Error

- `type WebSearchToolResultError struct{…}`

  - `ErrorCode WebSearchToolResultErrorCode`

    - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

    - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

    - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

    - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

    - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

    - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

  - `Type WebSearchToolResultError`

    - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

### Web Search Tool Result Error Code

- `type WebSearchToolResultErrorCode string`

  - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

  - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

  - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

  - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

  - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

  - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

# Batches

## Create a Message Batch

`client.Messages.Batches.New(ctx, body) (*MessageBatch, error)`

**post** `/v1/messages/batches`

Send a batch of Message creation requests.

The Message Batches API can be used to process multiple Messages API requests at once. Once a Message Batch is created, it begins processing immediately. Batches can take up to 24 hours to complete.

Learn more about the Message Batches API in our [user guide](https://docs.claude.com/en/docs/build-with-claude/batch-processing)

### Parameters

- `body MessageBatchNewParams`

  - `Requests param.Field[[]MessageBatchNewParamsRequest]`

    List of requests for prompt completion. Each is an individual request to create a Message.

    - `CustomID string`

      Developer-provided ID created for each request in a Message Batch. Useful for matching results to requests, as results may be given out of request order.

      Must be unique for each request within the Message Batch.

    - `Params MessageBatchNewParamsRequestParams`

      Messages API creation parameters for the individual request.

      See the [Messages API reference](https://docs.claude.com/en/api/messages) for full documentation on available parameters.

      - `MaxTokens int64`

        The maximum number of tokens to generate before stopping.

        Note that our models may stop _before_ reaching this maximum. This parameter only specifies the absolute maximum number of tokens to generate.

        Set to `0` to populate the [prompt cache](https://docs.claude.com/en/docs/build-with-claude/prompt-caching#pre-warming-the-cache) without generating a response.

        Different models have different maximum values for this parameter.  See [models](https://docs.claude.com/en/docs/models-overview) for details.

      - `Messages []MessageParamResp`

        Input messages.

        Our models are trained to operate on alternating `user` and `assistant` conversational turns. When creating a new `Message`, you specify the prior conversational turns with the `messages` parameter, and the model then generates the next `Message` in the conversation. Consecutive `user` or `assistant` turns in your request will be combined into a single turn.

        Each input message must be an object with a `role` and `content`. You can specify a single `user`-role message, or you can include multiple `user` and `assistant` messages.

        If the final message uses the `assistant` role, the response content will continue immediately from the content in that message. This can be used to constrain part of the model's response.

        Example with a single `user` message:

        ```json
        [{"role": "user", "content": "Hello, Claude"}]
        ```

        Example with multiple conversational turns:

        ```json
        [
          {"role": "user", "content": "Hello there."},
          {"role": "assistant", "content": "Hi, I'm Claude. How can I help you?"},
          {"role": "user", "content": "Can you explain LLMs in plain English?"},
        ]
        ```

        Example with a partially-filled response from Claude:

        ```json
        [
          {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
          {"role": "assistant", "content": "The best answer is ("},
        ]
        ```

        Each input message `content` may be either a single `string` or an array of content blocks, where each block has a specific `type`. Using a `string` for `content` is shorthand for an array of one content block of type `"text"`. The following input messages are equivalent:

        ```json
        {"role": "user", "content": "Hello, Claude"}
        ```

        ```json
        {"role": "user", "content": [{"type": "text", "text": "Hello, Claude"}]}
        ```

        See [input examples](https://docs.claude.com/en/api/messages-examples).

        Note that if you want to include a [system prompt](https://docs.claude.com/en/docs/system-prompts), you can use the top-level `system` parameter — there is no `"system"` role for input messages in the Messages API.

        There is a limit of 100,000 messages in a single request.

        - `Content []ContentBlockParamUnionResp`

          - `[]ContentBlockParamUnionResp`

            - `type TextBlockParamResp struct{…}`

              - `Text string`

              - `Type Text`

                - `const TextText Text = "text"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

                - `Type Ephemeral`

                  - `const EphemeralEphemeral Ephemeral = "ephemeral"`

                - `TTL CacheControlEphemeralTTL`

                  The time-to-live for the cache control breakpoint.

                  This may be one the following values:

                  - `5m`: 5 minutes
                  - `1h`: 1 hour

                  Defaults to `5m`.

                  - `const CacheControlEphemeralTTLTTL5m CacheControlEphemeralTTL = "5m"`

                  - `const CacheControlEphemeralTTLTTL1h CacheControlEphemeralTTL = "1h"`

              - `Citations []TextCitationParamUnionResp`

                - `type CitationCharLocationParamResp struct{…}`

                  - `CitedText string`

                  - `DocumentIndex int64`

                  - `DocumentTitle string`

                  - `EndCharIndex int64`

                  - `StartCharIndex int64`

                  - `Type CharLocation`

                    - `const CharLocationCharLocation CharLocation = "char_location"`

                - `type CitationPageLocationParamResp struct{…}`

                  - `CitedText string`

                  - `DocumentIndex int64`

                  - `DocumentTitle string`

                  - `EndPageNumber int64`

                  - `StartPageNumber int64`

                  - `Type PageLocation`

                    - `const PageLocationPageLocation PageLocation = "page_location"`

                - `type CitationContentBlockLocationParamResp struct{…}`

                  - `CitedText string`

                    The full text of the cited block range, concatenated.

                    Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                  - `DocumentIndex int64`

                  - `DocumentTitle string`

                  - `EndBlockIndex int64`

                    Exclusive 0-based end index of the cited block range in the source's `content` array.

                    Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                  - `StartBlockIndex int64`

                    0-based index of the first cited block in the source's `content` array.

                  - `Type ContentBlockLocation`

                    - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

                - `type CitationWebSearchResultLocationParamResp struct{…}`

                  - `CitedText string`

                  - `EncryptedIndex string`

                  - `Title string`

                  - `Type WebSearchResultLocation`

                    - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

                  - `URL string`

                - `type CitationSearchResultLocationParamResp struct{…}`

                  - `CitedText string`

                    The full text of the cited block range, concatenated.

                    Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                  - `EndBlockIndex int64`

                    Exclusive 0-based end index of the cited block range in the source's `content` array.

                    Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                  - `SearchResultIndex int64`

                    0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                    Counted separately from `document_index`; server-side web search results are not included in this count.

                  - `Source string`

                  - `StartBlockIndex int64`

                    0-based index of the first cited block in the source's `content` array.

                  - `Title string`

                  - `Type SearchResultLocation`

                    - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

            - `type ImageBlockParamResp struct{…}`

              - `Source ImageBlockParamSourceUnionResp`

                - `type Base64ImageSource struct{…}`

                  - `Data string`

                  - `MediaType Base64ImageSourceMediaType`

                    - `const Base64ImageSourceMediaTypeImageJPEG Base64ImageSourceMediaType = "image/jpeg"`

                    - `const Base64ImageSourceMediaTypeImagePNG Base64ImageSourceMediaType = "image/png"`

                    - `const Base64ImageSourceMediaTypeImageGIF Base64ImageSourceMediaType = "image/gif"`

                    - `const Base64ImageSourceMediaTypeImageWebP Base64ImageSourceMediaType = "image/webp"`

                  - `Type Base64`

                    - `const Base64Base64 Base64 = "base64"`

                - `type URLImageSource struct{…}`

                  - `Type URL`

                    - `const URLURL URL = "url"`

                  - `URL string`

              - `Type Image`

                - `const ImageImage Image = "image"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

            - `type DocumentBlockParamResp struct{…}`

              - `Source DocumentBlockParamSourceUnionResp`

                - `type Base64PDFSource struct{…}`

                  - `Data string`

                  - `MediaType ApplicationPDF`

                    - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                  - `Type Base64`

                    - `const Base64Base64 Base64 = "base64"`

                - `type PlainTextSource struct{…}`

                  - `Data string`

                  - `MediaType TextPlain`

                    - `const TextPlainTextPlain TextPlain = "text/plain"`

                  - `Type Text`

                    - `const TextText Text = "text"`

                - `type ContentBlockSource struct{…}`

                  - `Content ContentBlockSourceContentUnion`

                    - `string`

                    - `[]ContentBlockSourceContentItemUnion`

                      - `type TextBlockParamResp struct{…}`

                      - `type ImageBlockParamResp struct{…}`

                  - `Type Content`

                    - `const ContentContent Content = "content"`

                - `type URLPDFSource struct{…}`

                  - `Type URL`

                    - `const URLURL URL = "url"`

                  - `URL string`

              - `Type Document`

                - `const DocumentDocument Document = "document"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

              - `Citations CitationsConfigParamResp`

                - `Enabled bool`

              - `Context string`

              - `Title string`

            - `type SearchResultBlockParamResp struct{…}`

              - `Content []TextBlockParamResp`

                - `Text string`

                - `Type Text`

                - `CacheControl CacheControlEphemeral`

                  Create a cache control breakpoint at this content block.

                - `Citations []TextCitationParamUnionResp`

              - `Source string`

              - `Title string`

              - `Type SearchResult`

                - `const SearchResultSearchResult SearchResult = "search_result"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

              - `Citations CitationsConfigParamResp`

            - `type ThinkingBlockParamResp struct{…}`

              - `Signature string`

              - `Thinking string`

              - `Type Thinking`

                - `const ThinkingThinking Thinking = "thinking"`

            - `type RedactedThinkingBlockParamResp struct{…}`

              - `Data string`

              - `Type RedactedThinking`

                - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

            - `type ToolUseBlockParamResp struct{…}`

              - `ID string`

              - `Input map[string, any]`

              - `Name string`

              - `Type ToolUse`

                - `const ToolUseToolUse ToolUse = "tool_use"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

              - `Caller ToolUseBlockParamCallerUnionResp`

                Tool invocation directly from the model.

                - `type DirectCaller struct{…}`

                  Tool invocation directly from the model.

                  - `Type Direct`

                    - `const DirectDirect Direct = "direct"`

                - `type ServerToolCaller struct{…}`

                  Tool invocation generated by a server-side tool.

                  - `ToolID string`

                  - `Type CodeExecution20250825`

                    - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

                - `type ServerToolCaller20260120 struct{…}`

                  - `ToolID string`

                  - `Type CodeExecution20260120`

                    - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

            - `type ToolResultBlockParamResp struct{…}`

              - `ToolUseID string`

              - `Type ToolResult`

                - `const ToolResultToolResult ToolResult = "tool_result"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

              - `Content []ToolResultBlockParamContentUnionResp`

                - `[]ToolResultBlockParamContentUnionResp`

                  - `type TextBlockParamResp struct{…}`

                  - `type ImageBlockParamResp struct{…}`

                  - `type SearchResultBlockParamResp struct{…}`

                  - `type DocumentBlockParamResp struct{…}`

                  - `type ToolReferenceBlockParamResp struct{…}`

                    Tool reference block that can be included in tool_result content.

                    - `ToolName string`

                    - `Type ToolReference`

                      - `const ToolReferenceToolReference ToolReference = "tool_reference"`

                    - `CacheControl CacheControlEphemeral`

                      Create a cache control breakpoint at this content block.

              - `IsError bool`

            - `type ServerToolUseBlockParamResp struct{…}`

              - `ID string`

              - `Input map[string, any]`

              - `Name ServerToolUseBlockParamName`

                - `const ServerToolUseBlockParamNameWebSearch ServerToolUseBlockParamName = "web_search"`

                - `const ServerToolUseBlockParamNameWebFetch ServerToolUseBlockParamName = "web_fetch"`

                - `const ServerToolUseBlockParamNameCodeExecution ServerToolUseBlockParamName = "code_execution"`

                - `const ServerToolUseBlockParamNameBashCodeExecution ServerToolUseBlockParamName = "bash_code_execution"`

                - `const ServerToolUseBlockParamNameTextEditorCodeExecution ServerToolUseBlockParamName = "text_editor_code_execution"`

                - `const ServerToolUseBlockParamNameToolSearchToolRegex ServerToolUseBlockParamName = "tool_search_tool_regex"`

                - `const ServerToolUseBlockParamNameToolSearchToolBm25 ServerToolUseBlockParamName = "tool_search_tool_bm25"`

              - `Type ServerToolUse`

                - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

              - `Caller ServerToolUseBlockParamCallerUnionResp`

                Tool invocation directly from the model.

                - `type DirectCaller struct{…}`

                  Tool invocation directly from the model.

                - `type ServerToolCaller struct{…}`

                  Tool invocation generated by a server-side tool.

                - `type ServerToolCaller20260120 struct{…}`

            - `type WebSearchToolResultBlockParamResp struct{…}`

              - `Content WebSearchToolResultBlockParamContentUnionResp`

                - `[]WebSearchResultBlockParamResp`

                  - `EncryptedContent string`

                  - `Title string`

                  - `Type WebSearchResult`

                    - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

                  - `URL string`

                  - `PageAge string`

                - `type WebSearchToolRequestError struct{…}`

                  - `ErrorCode WebSearchToolResultErrorCode`

                    - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

                    - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

                    - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

                    - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

                    - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

                    - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

                  - `Type WebSearchToolResultError`

                    - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

              - `ToolUseID string`

              - `Type WebSearchToolResult`

                - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

              - `Caller WebSearchToolResultBlockParamCallerUnionResp`

                Tool invocation directly from the model.

                - `type DirectCaller struct{…}`

                  Tool invocation directly from the model.

                - `type ServerToolCaller struct{…}`

                  Tool invocation generated by a server-side tool.

                - `type ServerToolCaller20260120 struct{…}`

            - `type WebFetchToolResultBlockParamResp struct{…}`

              - `Content WebFetchToolResultBlockParamContentUnionResp`

                - `type WebFetchToolResultErrorBlockParamResp struct{…}`

                  - `ErrorCode WebFetchToolResultErrorCode`

                    - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

                    - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

                    - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

                    - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

                    - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

                    - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

                    - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

                    - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

                    - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

                  - `Type WebFetchToolResultError`

                    - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

                - `type WebFetchBlockParamResp struct{…}`

                  - `Content DocumentBlockParamResp`

                  - `Type WebFetchResult`

                    - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

                  - `URL string`

                    Fetched content URL

                  - `RetrievedAt string`

                    ISO 8601 timestamp when the content was retrieved

              - `ToolUseID string`

              - `Type WebFetchToolResult`

                - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

              - `Caller WebFetchToolResultBlockParamCallerUnionResp`

                Tool invocation directly from the model.

                - `type DirectCaller struct{…}`

                  Tool invocation directly from the model.

                - `type ServerToolCaller struct{…}`

                  Tool invocation generated by a server-side tool.

                - `type ServerToolCaller20260120 struct{…}`

            - `type CodeExecutionToolResultBlockParamResp struct{…}`

              - `Content CodeExecutionToolResultBlockParamContentUnionResp`

                Code execution result with encrypted stdout for PFC + web_search results.

                - `type CodeExecutionToolResultErrorParamResp struct{…}`

                  - `ErrorCode CodeExecutionToolResultErrorCode`

                    - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

                    - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

                    - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

                    - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                  - `Type CodeExecutionToolResultError`

                    - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

                - `type CodeExecutionResultBlockParamResp struct{…}`

                  - `Content []CodeExecutionOutputBlockParamResp`

                    - `FileID string`

                    - `Type CodeExecutionOutput`

                      - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

                  - `ReturnCode int64`

                  - `Stderr string`

                  - `Stdout string`

                  - `Type CodeExecutionResult`

                    - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

                - `type EncryptedCodeExecutionResultBlockParamResp struct{…}`

                  Code execution result with encrypted stdout for PFC + web_search results.

                  - `Content []CodeExecutionOutputBlockParamResp`

                    - `FileID string`

                    - `Type CodeExecutionOutput`

                  - `EncryptedStdout string`

                  - `ReturnCode int64`

                  - `Stderr string`

                  - `Type EncryptedCodeExecutionResult`

                    - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

              - `ToolUseID string`

              - `Type CodeExecutionToolResult`

                - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

            - `type BashCodeExecutionToolResultBlockParamResp struct{…}`

              - `Content BashCodeExecutionToolResultBlockParamContentUnionResp`

                - `type BashCodeExecutionToolResultErrorParamResp struct{…}`

                  - `ErrorCode BashCodeExecutionToolResultErrorCode`

                    - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                    - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

                    - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

                    - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                    - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

                  - `Type BashCodeExecutionToolResultError`

                    - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

                - `type BashCodeExecutionResultBlockParamResp struct{…}`

                  - `Content []BashCodeExecutionOutputBlockParamResp`

                    - `FileID string`

                    - `Type BashCodeExecutionOutput`

                      - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

                  - `ReturnCode int64`

                  - `Stderr string`

                  - `Stdout string`

                  - `Type BashCodeExecutionResult`

                    - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

              - `ToolUseID string`

              - `Type BashCodeExecutionToolResult`

                - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

            - `type TextEditorCodeExecutionToolResultBlockParamResp struct{…}`

              - `Content TextEditorCodeExecutionToolResultBlockParamContentUnionResp`

                - `type TextEditorCodeExecutionToolResultErrorParamResp struct{…}`

                  - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

                    - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                    - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

                    - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

                    - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                    - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

                  - `Type TextEditorCodeExecutionToolResultError`

                    - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

                  - `ErrorMessage string`

                - `type TextEditorCodeExecutionViewResultBlockParamResp struct{…}`

                  - `Content string`

                  - `FileType TextEditorCodeExecutionViewResultBlockParamFileType`

                    - `const TextEditorCodeExecutionViewResultBlockParamFileTypeText TextEditorCodeExecutionViewResultBlockParamFileType = "text"`

                    - `const TextEditorCodeExecutionViewResultBlockParamFileTypeImage TextEditorCodeExecutionViewResultBlockParamFileType = "image"`

                    - `const TextEditorCodeExecutionViewResultBlockParamFileTypePDF TextEditorCodeExecutionViewResultBlockParamFileType = "pdf"`

                  - `Type TextEditorCodeExecutionViewResult`

                    - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

                  - `NumLines int64`

                  - `StartLine int64`

                  - `TotalLines int64`

                - `type TextEditorCodeExecutionCreateResultBlockParamResp struct{…}`

                  - `IsFileUpdate bool`

                  - `Type TextEditorCodeExecutionCreateResult`

                    - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

                - `type TextEditorCodeExecutionStrReplaceResultBlockParamResp struct{…}`

                  - `Type TextEditorCodeExecutionStrReplaceResult`

                    - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

                  - `Lines []string`

                  - `NewLines int64`

                  - `NewStart int64`

                  - `OldLines int64`

                  - `OldStart int64`

              - `ToolUseID string`

              - `Type TextEditorCodeExecutionToolResult`

                - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

            - `type ToolSearchToolResultBlockParamResp struct{…}`

              - `Content ToolSearchToolResultBlockParamContentUnionResp`

                - `type ToolSearchToolResultErrorParamResp struct{…}`

                  - `ErrorCode ToolSearchToolResultErrorCode`

                    - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

                    - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

                    - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

                    - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

                  - `Type ToolSearchToolResultError`

                    - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

                  - `ErrorMessage string`

                - `type ToolSearchToolSearchResultBlockParamResp struct{…}`

                  - `ToolReferences []ToolReferenceBlockParamResp`

                    - `ToolName string`

                    - `Type ToolReference`

                    - `CacheControl CacheControlEphemeral`

                      Create a cache control breakpoint at this content block.

                  - `Type ToolSearchToolSearchResult`

                    - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

              - `ToolUseID string`

              - `Type ToolSearchToolResult`

                - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

            - `type ContainerUploadBlockParamResp struct{…}`

              A content block that represents a file to be uploaded to the container
              Files uploaded via this block will be available in the container's input directory.

              - `FileID string`

              - `Type ContainerUpload`

                - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

            - `type MidConversationSystemBlockParamResp struct{…}`

              System instructions that appear mid-conversation.

              Use this block to provide or update system-level instructions at a specific
              point in the conversation, rather than only via the top-level `system` parameter.

              - `Content []TextBlockParamResp`

                System instruction text blocks.

                - `Text string`

                - `Type Text`

                - `CacheControl CacheControlEphemeral`

                  Create a cache control breakpoint at this content block.

                - `Citations []TextCitationParamUnionResp`

              - `Type MidConvSystem`

                - `const MidConvSystemMidConvSystem MidConvSystem = "mid_conv_system"`

              - `CacheControl CacheControlEphemeral`

                Create a cache control breakpoint at this content block.

        - `Role MessageParamRole`

          - `const MessageParamRoleUser MessageParamRole = "user"`

          - `const MessageParamRoleAssistant MessageParamRole = "assistant"`

          - `const MessageParamRoleSystem MessageParamRole = "system"`

      - `Model Model`

        The model that will complete your prompt.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `type Model string`

          The model that will complete your prompt.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `const ModelClaudeFable5 Model = "claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

            Most capable model for cybersecurity and biology research

          - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

            New class of intelligence, strongest in coding and cybersecurity

          - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

            Frontier intelligence for long-running agents and coding

          - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

          - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

            Exceptional model for specialized complex tasks

          - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

            Exceptional model for specialized complex tasks

          - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

            Powerful model for complex tasks

          - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

            Powerful model for complex tasks

          - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

            High-performance model with extended thinking

          - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

            High-performance model with extended thinking

          - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

            Fast and cost-effective model

        - `string`

      - `CacheControl CacheControlEphemeral`

        Top-level cache control automatically applies a cache_control marker to the last cacheable block in the request.

      - `Container string`

        Container identifier for reuse across requests.

      - `InferenceGeo string`

        Specifies the geographic region for inference processing. If not specified, the workspace's `default_inference_geo` is used.

      - `Metadata Metadata`

        An object describing metadata about the request.

        - `UserID string`

          An external identifier for the user who is associated with the request.

          This should be a uuid, hash value, or other opaque identifier. Anthropic may use this id to help detect abuse. Do not include any identifying information such as name, email address, or phone number.

      - `OutputConfig OutputConfig`

        Configuration options for the model's output, such as the output format.

        - `Effort OutputConfigEffort`

          All possible effort levels.

          - `const OutputConfigEffortLow OutputConfigEffort = "low"`

          - `const OutputConfigEffortMedium OutputConfigEffort = "medium"`

          - `const OutputConfigEffortHigh OutputConfigEffort = "high"`

          - `const OutputConfigEffortXhigh OutputConfigEffort = "xhigh"`

          - `const OutputConfigEffortMax OutputConfigEffort = "max"`

        - `Format JSONOutputFormat`

          A schema to specify Claude's output format in responses. See [structured outputs](https://platform.claude.com/docs/en/build-with-claude/structured-outputs)

          - `Schema map[string, any]`

            The JSON schema of the format

          - `Type JSONSchema`

            - `const JSONSchemaJSONSchema JSONSchema = "json_schema"`

      - `ServiceTier string`

        Determines whether to use priority capacity (if available) or standard capacity for this request.

        Anthropic offers different levels of service for your API requests. See [service-tiers](https://docs.claude.com/en/api/service-tiers) for details.

        - `const MessageBatchNewParamsRequestParamsServiceTierAuto MessageBatchNewParamsRequestParamsServiceTier = "auto"`

        - `const MessageBatchNewParamsRequestParamsServiceTierStandardOnly MessageBatchNewParamsRequestParamsServiceTier = "standard_only"`

      - `StopSequences []string`

        Custom text sequences that will cause the model to stop generating.

        Our models will normally stop when they have naturally completed their turn, which will result in a response `stop_reason` of `"end_turn"`.

        If you want the model to stop generating when it encounters custom strings of text, you can use the `stop_sequences` parameter. If the model encounters one of the custom sequences, the response `stop_reason` value will be `"stop_sequence"` and the response `stop_sequence` value will contain the matched stop sequence.

      - `Stream bool`

        Whether to incrementally stream the response using server-sent events.

        See [streaming](https://docs.claude.com/en/api/messages-streaming) for details.

      - `System []TextBlockParamResp`

        System prompt.

        A system prompt is a way of providing context and instructions to Claude, such as specifying a particular goal or role. See our [guide to system prompts](https://docs.claude.com/en/docs/system-prompts).

        - `[]TextBlockParam`

          - `Text string`

          - `Type Text`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations []TextCitationParamUnionResp`

      - `Temperature float64`

        Amount of randomness injected into the response.

        Defaults to `1.0`. Ranges from `0.0` to `1.0`. Use `temperature` closer to `0.0` for analytical / multiple choice, and closer to `1.0` for creative and generative tasks.

        Note that even with `temperature` of `0.0`, the results will not be fully deterministic.

      - `Thinking ThinkingConfigParamUnionResp`

        Configuration for enabling Claude's extended thinking.

        When enabled, responses include `thinking` content blocks showing Claude's thinking process before the final answer. Requires a minimum budget of 1,024 tokens and counts towards your `max_tokens` limit.

        See [extended thinking](https://docs.claude.com/en/docs/build-with-claude/extended-thinking) for details.

        - `type ThinkingConfigEnabled struct{…}`

          - `BudgetTokens int64`

            Determines how many tokens Claude can use for its internal reasoning process. Larger budgets can enable more thorough analysis for complex problems, improving response quality.

            Must be ≥1024 and less than `max_tokens`.

            See [extended thinking](https://docs.claude.com/en/docs/build-with-claude/extended-thinking) for details.

          - `Type Enabled`

            - `const EnabledEnabled Enabled = "enabled"`

          - `Display ThinkingConfigEnabledDisplay`

            Controls how thinking content appears in the response. When set to `summarized`, thinking is returned normally. When set to `omitted`, thinking content is redacted but a signature is returned for multi-turn continuity. Defaults to `summarized`.

            - `const ThinkingConfigEnabledDisplaySummarized ThinkingConfigEnabledDisplay = "summarized"`

            - `const ThinkingConfigEnabledDisplayOmitted ThinkingConfigEnabledDisplay = "omitted"`

        - `type ThinkingConfigDisabled struct{…}`

          - `Type Disabled`

            - `const DisabledDisabled Disabled = "disabled"`

        - `type ThinkingConfigAdaptive struct{…}`

          - `Type Adaptive`

            - `const AdaptiveAdaptive Adaptive = "adaptive"`

          - `Display ThinkingConfigAdaptiveDisplay`

            Controls how thinking content appears in the response. When set to `summarized`, thinking is returned normally. When set to `omitted`, thinking content is redacted but a signature is returned for multi-turn continuity. Defaults to `summarized`.

            - `const ThinkingConfigAdaptiveDisplaySummarized ThinkingConfigAdaptiveDisplay = "summarized"`

            - `const ThinkingConfigAdaptiveDisplayOmitted ThinkingConfigAdaptiveDisplay = "omitted"`

      - `ToolChoice ToolChoiceUnion`

        How the model should use the provided tools. The model can use a specific tool, any available tool, decide by itself, or not use tools at all.

        - `type ToolChoiceAuto struct{…}`

          The model will automatically decide whether to use tools.

          - `Type Auto`

            - `const AutoAuto Auto = "auto"`

          - `DisableParallelToolUse bool`

            Whether to disable parallel tool use.

            Defaults to `false`. If set to `true`, the model will output at most one tool use.

        - `type ToolChoiceAny struct{…}`

          The model will use any available tools.

          - `Type Any`

            - `const AnyAny Any = "any"`

          - `DisableParallelToolUse bool`

            Whether to disable parallel tool use.

            Defaults to `false`. If set to `true`, the model will output exactly one tool use.

        - `type ToolChoiceTool struct{…}`

          The model will use the specified tool with `tool_choice.name`.

          - `Name string`

            The name of the tool to use.

          - `Type Tool`

            - `const ToolTool Tool = "tool"`

          - `DisableParallelToolUse bool`

            Whether to disable parallel tool use.

            Defaults to `false`. If set to `true`, the model will output exactly one tool use.

        - `type ToolChoiceNone struct{…}`

          The model will not be allowed to use tools.

          - `Type None`

            - `const NoneNone None = "none"`

      - `Tools []ToolUnion`

        Definitions of tools that the model may use.

        If you include `tools` in your API request, the model may return `tool_use` content blocks that represent the model's use of those tools. You can then run those tools using the tool input generated by the model and then optionally return results back to the model using `tool_result` content blocks.

        There are two types of tools: **client tools** and **server tools**. The behavior described below applies to client tools. For [server tools](https://docs.claude.com/en/docs/agents-and-tools/tool-use/overview#server-tools), see their individual documentation as each has its own behavior (e.g., the [web search tool](https://docs.claude.com/en/docs/agents-and-tools/tool-use/web-search-tool)).

        Each tool definition includes:

        * `name`: Name of the tool.
        * `description`: Optional, but strongly-recommended description of the tool.
        * `input_schema`: [JSON schema](https://json-schema.org/draft/2020-12) for the tool `input` shape that the model will produce in `tool_use` output content blocks.

        For example, if you defined `tools` as:

        ```json
        [
          {
            "name": "get_stock_price",
            "description": "Get the current stock price for a given ticker symbol.",
            "input_schema": {
              "type": "object",
              "properties": {
                "ticker": {
                  "type": "string",
                  "description": "The stock ticker symbol, e.g. AAPL for Apple Inc."
                }
              },
              "required": ["ticker"]
            }
          }
        ]
        ```

        And then asked the model "What's the S&P 500 at today?", the model might produce `tool_use` content blocks in the response like this:

        ```json
        [
          {
            "type": "tool_use",
            "id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
            "name": "get_stock_price",
            "input": { "ticker": "^GSPC" }
          }
        ]
        ```

        You might then run your `get_stock_price` tool with `{"ticker": "^GSPC"}` as an input, and return the following back to the model in a subsequent `user` message:

        ```json
        [
          {
            "type": "tool_result",
            "tool_use_id": "toolu_01D7FLrfh4GYq7yT1ULFeyMV",
            "content": "259.75 USD"
          }
        ]
        ```

        Tools can be used for workflows that include running client-side tools and functions, or more generally whenever you want the model to produce a particular JSON structure of output.

        See our [guide](https://docs.claude.com/en/docs/tool-use) for more details.

        - `type Tool struct{…}`

          - `InputSchema ToolInputSchema`

            [JSON schema](https://json-schema.org/draft/2020-12) for this tool's input.

            This defines the shape of the `input` that your tool accepts and that the model will produce.

            - `Type Object`

              - `const ObjectObject Object = "object"`

            - `Properties map[string, any]`

            - `Required []string`

          - `Name string`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

          - `AllowedCallers []string`

            - `const ToolAllowedCallerDirect ToolAllowedCaller = "direct"`

            - `const ToolAllowedCallerCodeExecution20250825 ToolAllowedCaller = "code_execution_20250825"`

            - `const ToolAllowedCallerCodeExecution20260120 ToolAllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `Description string`

            Description of what this tool does.

            Tool descriptions should be as detailed as possible. The more information that the model has about what the tool is and how to use it, the better it will perform. You can use natural language descriptions to reinforce important aspects of the tool input JSON schema.

          - `EagerInputStreaming bool`

            Enable eager input streaming for this tool. When true, tool input parameters will be streamed incrementally as they are generated, and types will be inferred on-the-fly rather than buffering the full JSON output. When false, streaming is disabled for this tool even if the fine-grained-tool-streaming beta is active. When null (default), uses the default behavior based on beta headers.

          - `InputExamples []map[string, any]`

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

          - `Type ToolType`

            - `const ToolTypeCustom ToolType = "custom"`

        - `type ToolBash20250124 struct{…}`

          - `Name Bash`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const BashBash Bash = "bash"`

          - `Type Bash20250124`

            - `const Bash20250124Bash20250124 Bash20250124 = "bash_20250124"`

          - `AllowedCallers []string`

            - `const ToolBash20250124AllowedCallerDirect ToolBash20250124AllowedCaller = "direct"`

            - `const ToolBash20250124AllowedCallerCodeExecution20250825 ToolBash20250124AllowedCaller = "code_execution_20250825"`

            - `const ToolBash20250124AllowedCallerCodeExecution20260120 ToolBash20250124AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `InputExamples []map[string, any]`

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type CodeExecutionTool20250522 struct{…}`

          - `Name CodeExecution`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

          - `Type CodeExecution20250522`

            - `const CodeExecution20250522CodeExecution20250522 CodeExecution20250522 = "code_execution_20250522"`

          - `AllowedCallers []string`

            - `const CodeExecutionTool20250522AllowedCallerDirect CodeExecutionTool20250522AllowedCaller = "direct"`

            - `const CodeExecutionTool20250522AllowedCallerCodeExecution20250825 CodeExecutionTool20250522AllowedCaller = "code_execution_20250825"`

            - `const CodeExecutionTool20250522AllowedCallerCodeExecution20260120 CodeExecutionTool20250522AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type CodeExecutionTool20250825 struct{…}`

          - `Name CodeExecution`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

          - `Type CodeExecution20250825`

            - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

          - `AllowedCallers []string`

            - `const CodeExecutionTool20250825AllowedCallerDirect CodeExecutionTool20250825AllowedCaller = "direct"`

            - `const CodeExecutionTool20250825AllowedCallerCodeExecution20250825 CodeExecutionTool20250825AllowedCaller = "code_execution_20250825"`

            - `const CodeExecutionTool20250825AllowedCallerCodeExecution20260120 CodeExecutionTool20250825AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type CodeExecutionTool20260120 struct{…}`

          Code execution tool with REPL state persistence (daemon mode + gVisor checkpoint).

          - `Name CodeExecution`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const CodeExecutionCodeExecution CodeExecution = "code_execution"`

          - `Type CodeExecution20260120`

            - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

          - `AllowedCallers []string`

            - `const CodeExecutionTool20260120AllowedCallerDirect CodeExecutionTool20260120AllowedCaller = "direct"`

            - `const CodeExecutionTool20260120AllowedCallerCodeExecution20250825 CodeExecutionTool20260120AllowedCaller = "code_execution_20250825"`

            - `const CodeExecutionTool20260120AllowedCallerCodeExecution20260120 CodeExecutionTool20260120AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type MemoryTool20250818 struct{…}`

          - `Name Memory`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const MemoryMemory Memory = "memory"`

          - `Type Memory20250818`

            - `const Memory20250818Memory20250818 Memory20250818 = "memory_20250818"`

          - `AllowedCallers []string`

            - `const MemoryTool20250818AllowedCallerDirect MemoryTool20250818AllowedCaller = "direct"`

            - `const MemoryTool20250818AllowedCallerCodeExecution20250825 MemoryTool20250818AllowedCaller = "code_execution_20250825"`

            - `const MemoryTool20250818AllowedCallerCodeExecution20260120 MemoryTool20250818AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `InputExamples []map[string, any]`

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type ToolTextEditor20250124 struct{…}`

          - `Name StrReplaceEditor`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const StrReplaceEditorStrReplaceEditor StrReplaceEditor = "str_replace_editor"`

          - `Type TextEditor20250124`

            - `const TextEditor20250124TextEditor20250124 TextEditor20250124 = "text_editor_20250124"`

          - `AllowedCallers []string`

            - `const ToolTextEditor20250124AllowedCallerDirect ToolTextEditor20250124AllowedCaller = "direct"`

            - `const ToolTextEditor20250124AllowedCallerCodeExecution20250825 ToolTextEditor20250124AllowedCaller = "code_execution_20250825"`

            - `const ToolTextEditor20250124AllowedCallerCodeExecution20260120 ToolTextEditor20250124AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `InputExamples []map[string, any]`

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type ToolTextEditor20250429 struct{…}`

          - `Name StrReplaceBasedEditTool`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

          - `Type TextEditor20250429`

            - `const TextEditor20250429TextEditor20250429 TextEditor20250429 = "text_editor_20250429"`

          - `AllowedCallers []string`

            - `const ToolTextEditor20250429AllowedCallerDirect ToolTextEditor20250429AllowedCaller = "direct"`

            - `const ToolTextEditor20250429AllowedCallerCodeExecution20250825 ToolTextEditor20250429AllowedCaller = "code_execution_20250825"`

            - `const ToolTextEditor20250429AllowedCallerCodeExecution20260120 ToolTextEditor20250429AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `InputExamples []map[string, any]`

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type ToolTextEditor20250728 struct{…}`

          - `Name StrReplaceBasedEditTool`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const StrReplaceBasedEditToolStrReplaceBasedEditTool StrReplaceBasedEditTool = "str_replace_based_edit_tool"`

          - `Type TextEditor20250728`

            - `const TextEditor20250728TextEditor20250728 TextEditor20250728 = "text_editor_20250728"`

          - `AllowedCallers []string`

            - `const ToolTextEditor20250728AllowedCallerDirect ToolTextEditor20250728AllowedCaller = "direct"`

            - `const ToolTextEditor20250728AllowedCallerCodeExecution20250825 ToolTextEditor20250728AllowedCaller = "code_execution_20250825"`

            - `const ToolTextEditor20250728AllowedCallerCodeExecution20260120 ToolTextEditor20250728AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `InputExamples []map[string, any]`

          - `MaxCharacters int64`

            Maximum number of characters to display when viewing a file. If not specified, defaults to displaying the full file.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type WebSearchTool20250305 struct{…}`

          - `Name WebSearch`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const WebSearchWebSearch WebSearch = "web_search"`

          - `Type WebSearch20250305`

            - `const WebSearch20250305WebSearch20250305 WebSearch20250305 = "web_search_20250305"`

          - `AllowedCallers []string`

            - `const WebSearchTool20250305AllowedCallerDirect WebSearchTool20250305AllowedCaller = "direct"`

            - `const WebSearchTool20250305AllowedCallerCodeExecution20250825 WebSearchTool20250305AllowedCaller = "code_execution_20250825"`

            - `const WebSearchTool20250305AllowedCallerCodeExecution20260120 WebSearchTool20250305AllowedCaller = "code_execution_20260120"`

          - `AllowedDomains []string`

            If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

          - `BlockedDomains []string`

            If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `MaxUses int64`

            Maximum number of times the tool can be used in the API request.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

          - `UserLocation UserLocation`

            Parameters for the user's location. Used to provide more relevant search results.

            - `Type Approximate`

              - `const ApproximateApproximate Approximate = "approximate"`

            - `City string`

              The city of the user.

            - `Country string`

              The two letter [ISO country code](https://en.wikipedia.org/wiki/ISO_3166-1_alpha-2) of the user.

            - `Region string`

              The region of the user.

            - `Timezone string`

              The [IANA timezone](https://nodatime.org/TimeZones) of the user.

        - `type WebFetchTool20250910 struct{…}`

          - `Name WebFetch`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const WebFetchWebFetch WebFetch = "web_fetch"`

          - `Type WebFetch20250910`

            - `const WebFetch20250910WebFetch20250910 WebFetch20250910 = "web_fetch_20250910"`

          - `AllowedCallers []string`

            - `const WebFetchTool20250910AllowedCallerDirect WebFetchTool20250910AllowedCaller = "direct"`

            - `const WebFetchTool20250910AllowedCallerCodeExecution20250825 WebFetchTool20250910AllowedCaller = "code_execution_20250825"`

            - `const WebFetchTool20250910AllowedCallerCodeExecution20260120 WebFetchTool20250910AllowedCaller = "code_execution_20260120"`

          - `AllowedDomains []string`

            List of domains to allow fetching from

          - `BlockedDomains []string`

            List of domains to block fetching from

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations CitationsConfigParamResp`

            Citations configuration for fetched documents. Citations are disabled by default.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `MaxContentTokens int64`

            Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

          - `MaxUses int64`

            Maximum number of times the tool can be used in the API request.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type WebSearchTool20260209 struct{…}`

          - `Name WebSearch`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const WebSearchWebSearch WebSearch = "web_search"`

          - `Type WebSearch20260209`

            - `const WebSearch20260209WebSearch20260209 WebSearch20260209 = "web_search_20260209"`

          - `AllowedCallers []string`

            - `const WebSearchTool20260209AllowedCallerDirect WebSearchTool20260209AllowedCaller = "direct"`

            - `const WebSearchTool20260209AllowedCallerCodeExecution20250825 WebSearchTool20260209AllowedCaller = "code_execution_20250825"`

            - `const WebSearchTool20260209AllowedCallerCodeExecution20260120 WebSearchTool20260209AllowedCaller = "code_execution_20260120"`

          - `AllowedDomains []string`

            If provided, only these domains will be included in results. Cannot be used alongside `blocked_domains`.

          - `BlockedDomains []string`

            If provided, these domains will never appear in results. Cannot be used alongside `allowed_domains`.

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `MaxUses int64`

            Maximum number of times the tool can be used in the API request.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

          - `UserLocation UserLocation`

            Parameters for the user's location. Used to provide more relevant search results.

        - `type WebFetchTool20260209 struct{…}`

          - `Name WebFetch`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const WebFetchWebFetch WebFetch = "web_fetch"`

          - `Type WebFetch20260209`

            - `const WebFetch20260209WebFetch20260209 WebFetch20260209 = "web_fetch_20260209"`

          - `AllowedCallers []string`

            - `const WebFetchTool20260209AllowedCallerDirect WebFetchTool20260209AllowedCaller = "direct"`

            - `const WebFetchTool20260209AllowedCallerCodeExecution20250825 WebFetchTool20260209AllowedCaller = "code_execution_20250825"`

            - `const WebFetchTool20260209AllowedCallerCodeExecution20260120 WebFetchTool20260209AllowedCaller = "code_execution_20260120"`

          - `AllowedDomains []string`

            List of domains to allow fetching from

          - `BlockedDomains []string`

            List of domains to block fetching from

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations CitationsConfigParamResp`

            Citations configuration for fetched documents. Citations are disabled by default.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `MaxContentTokens int64`

            Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

          - `MaxUses int64`

            Maximum number of times the tool can be used in the API request.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type WebFetchTool20260309 struct{…}`

          Web fetch tool with use_cache parameter for bypassing cached content.

          - `Name WebFetch`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const WebFetchWebFetch WebFetch = "web_fetch"`

          - `Type WebFetch20260309`

            - `const WebFetch20260309WebFetch20260309 WebFetch20260309 = "web_fetch_20260309"`

          - `AllowedCallers []string`

            - `const WebFetchTool20260309AllowedCallerDirect WebFetchTool20260309AllowedCaller = "direct"`

            - `const WebFetchTool20260309AllowedCallerCodeExecution20250825 WebFetchTool20260309AllowedCaller = "code_execution_20250825"`

            - `const WebFetchTool20260309AllowedCallerCodeExecution20260120 WebFetchTool20260309AllowedCaller = "code_execution_20260120"`

          - `AllowedDomains []string`

            List of domains to allow fetching from

          - `BlockedDomains []string`

            List of domains to block fetching from

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `Citations CitationsConfigParamResp`

            Citations configuration for fetched documents. Citations are disabled by default.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `MaxContentTokens int64`

            Maximum number of tokens used by including web page text content in the context. The limit is approximate and does not apply to binary content such as PDFs.

          - `MaxUses int64`

            Maximum number of times the tool can be used in the API request.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

          - `UseCache bool`

            Whether to use cached content. Set to false to bypass the cache and fetch fresh content. Only set to false when the user explicitly requests fresh content or when fetching rapidly-changing sources.

        - `type ToolSearchToolBm25_20251119 struct{…}`

          - `Name ToolSearchToolBm25`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const ToolSearchToolBm25ToolSearchToolBm25 ToolSearchToolBm25 = "tool_search_tool_bm25"`

          - `Type ToolSearchToolBm25_20251119Type`

            - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25_20251119 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25_20251119"`

            - `const ToolSearchToolBm25_20251119TypeToolSearchToolBm25 ToolSearchToolBm25_20251119Type = "tool_search_tool_bm25"`

          - `AllowedCallers []string`

            - `const ToolSearchToolBm25_20251119AllowedCallerDirect ToolSearchToolBm25_20251119AllowedCaller = "direct"`

            - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20250825 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20250825"`

            - `const ToolSearchToolBm25_20251119AllowedCallerCodeExecution20260120 ToolSearchToolBm25_20251119AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

        - `type ToolSearchToolRegex20251119 struct{…}`

          - `Name ToolSearchToolRegex`

            Name of the tool.

            This is how the tool will be called by the model and in `tool_use` blocks.

            - `const ToolSearchToolRegexToolSearchToolRegex ToolSearchToolRegex = "tool_search_tool_regex"`

          - `Type ToolSearchToolRegex20251119Type`

            - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex20251119 ToolSearchToolRegex20251119Type = "tool_search_tool_regex_20251119"`

            - `const ToolSearchToolRegex20251119TypeToolSearchToolRegex ToolSearchToolRegex20251119Type = "tool_search_tool_regex"`

          - `AllowedCallers []string`

            - `const ToolSearchToolRegex20251119AllowedCallerDirect ToolSearchToolRegex20251119AllowedCaller = "direct"`

            - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20250825 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20250825"`

            - `const ToolSearchToolRegex20251119AllowedCallerCodeExecution20260120 ToolSearchToolRegex20251119AllowedCaller = "code_execution_20260120"`

          - `CacheControl CacheControlEphemeral`

            Create a cache control breakpoint at this content block.

          - `DeferLoading bool`

            If true, tool will not be included in initial system prompt. Only loaded when returned via tool_reference from tool search.

          - `Strict bool`

            When true, guarantees schema validation on tool names and inputs

      - `TopK int64`

        Only sample from the top K options for each subsequent token.

        Used to remove "long tail" low probability responses. [Learn more technical details here](https://towardsdatascience.com/how-to-sample-from-language-models-682bceb97277).

        Recommended for advanced use cases only.

      - `TopP float64`

        Use nucleus sampling.

        In nucleus sampling, we compute the cumulative distribution over all the options for each subsequent token in decreasing probability order and cut it off once it reaches a particular probability specified by `top_p`.

        Recommended for advanced use cases only.

### Returns

- `type MessageBatch struct{…}`

  - `ID string`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `ArchivedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  - `CancelInitiatedAt Time`

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  - `CreatedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  - `EndedAt Time`

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  - `ExpiresAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  - `ProcessingStatus MessageBatchProcessingStatus`

    Processing status of the Message Batch.

    - `const MessageBatchProcessingStatusInProgress MessageBatchProcessingStatus = "in_progress"`

    - `const MessageBatchProcessingStatusCanceling MessageBatchProcessingStatus = "canceling"`

    - `const MessageBatchProcessingStatusEnded MessageBatchProcessingStatus = "ended"`

  - `RequestCounts MessageBatchRequestCounts`

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as `processing` and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    - `Canceled int64`

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    - `Errored int64`

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    - `Expired int64`

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    - `Processing int64`

      Number of requests in the Message Batch that are processing.

    - `Succeeded int64`

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  - `ResultsURL string`

    URL to a `.jsonl` file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the `custom_id` field to match results to requests.

  - `Type MessageBatch`

    Object type.

    For Message Batches, this is always `"message_batch"`.

    - `const MessageBatchMessageBatch MessageBatch = "message_batch"`

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/anthropics/anthropic-sdk-go"
  "github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
  client := anthropic.NewClient(
    option.WithAPIKey("my-anthropic-api-key"),
  )
  messageBatch, err := client.Messages.Batches.New(context.TODO(), anthropic.MessageBatchNewParams{
    Requests: []anthropic.MessageBatchNewParamsRequest{anthropic.MessageBatchNewParamsRequest{
      CustomID: "my-custom-id-1",
      Params: anthropic.MessageBatchNewParamsRequestParams{
        MaxTokens: 1024,
        Messages: []anthropic.MessageParam{anthropic.MessageParam{
          Content: []anthropic.ContentBlockParamUnion{anthropic.ContentBlockParamUnion{
            OfText: &anthropic.TextBlockParam{
              Text: "x",
            },
          }},
          Role: anthropic.MessageParamRoleUser,
        }},
        Model: anthropic.ModelClaudeOpus4_6,
      },
    }},
  })
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", messageBatch.ID)
}
```

#### Response

```json
{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "archived_at": "2024-08-20T18:37:24.100435Z",
  "cancel_initiated_at": "2024-08-20T18:37:24.100435Z",
  "created_at": "2024-08-20T18:37:24.100435Z",
  "ended_at": "2024-08-20T18:37:24.100435Z",
  "expires_at": "2024-08-20T18:37:24.100435Z",
  "processing_status": "in_progress",
  "request_counts": {
    "canceled": 10,
    "errored": 30,
    "expired": 10,
    "processing": 100,
    "succeeded": 50
  },
  "results_url": "https://api.anthropic.com/v1/messages/batches/msgbatch_013Zva2CMHLNnXjNJJKqJ2EF/results",
  "type": "message_batch"
}
```

## Retrieve a Message Batch

`client.Messages.Batches.Get(ctx, messageBatchID) (*MessageBatch, error)`

**get** `/v1/messages/batches/{message_batch_id}`

This endpoint is idempotent and can be used to poll for Message Batch completion. To access the results of a Message Batch, make a request to the `results_url` field in the response.

Learn more about the Message Batches API in our [user guide](https://docs.claude.com/en/docs/build-with-claude/batch-processing)

### Parameters

- `messageBatchID string`

  ID of the Message Batch.

### Returns

- `type MessageBatch struct{…}`

  - `ID string`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `ArchivedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  - `CancelInitiatedAt Time`

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  - `CreatedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  - `EndedAt Time`

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  - `ExpiresAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  - `ProcessingStatus MessageBatchProcessingStatus`

    Processing status of the Message Batch.

    - `const MessageBatchProcessingStatusInProgress MessageBatchProcessingStatus = "in_progress"`

    - `const MessageBatchProcessingStatusCanceling MessageBatchProcessingStatus = "canceling"`

    - `const MessageBatchProcessingStatusEnded MessageBatchProcessingStatus = "ended"`

  - `RequestCounts MessageBatchRequestCounts`

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as `processing` and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    - `Canceled int64`

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    - `Errored int64`

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    - `Expired int64`

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    - `Processing int64`

      Number of requests in the Message Batch that are processing.

    - `Succeeded int64`

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  - `ResultsURL string`

    URL to a `.jsonl` file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the `custom_id` field to match results to requests.

  - `Type MessageBatch`

    Object type.

    For Message Batches, this is always `"message_batch"`.

    - `const MessageBatchMessageBatch MessageBatch = "message_batch"`

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/anthropics/anthropic-sdk-go"
  "github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
  client := anthropic.NewClient(
    option.WithAPIKey("my-anthropic-api-key"),
  )
  messageBatch, err := client.Messages.Batches.Get(context.TODO(), "message_batch_id")
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", messageBatch.ID)
}
```

#### Response

```json
{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "archived_at": "2024-08-20T18:37:24.100435Z",
  "cancel_initiated_at": "2024-08-20T18:37:24.100435Z",
  "created_at": "2024-08-20T18:37:24.100435Z",
  "ended_at": "2024-08-20T18:37:24.100435Z",
  "expires_at": "2024-08-20T18:37:24.100435Z",
  "processing_status": "in_progress",
  "request_counts": {
    "canceled": 10,
    "errored": 30,
    "expired": 10,
    "processing": 100,
    "succeeded": 50
  },
  "results_url": "https://api.anthropic.com/v1/messages/batches/msgbatch_013Zva2CMHLNnXjNJJKqJ2EF/results",
  "type": "message_batch"
}
```

## List Message Batches

`client.Messages.Batches.List(ctx, query) (*Page[MessageBatch], error)`

**get** `/v1/messages/batches`

List all Message Batches within a Workspace. Most recently created batches are returned first.

Learn more about the Message Batches API in our [user guide](https://docs.claude.com/en/docs/build-with-claude/batch-processing)

### Parameters

- `query MessageBatchListParams`

  - `AfterID param.Field[string]`

    ID of the object to use as a cursor for pagination. When provided, returns the page of results immediately after this object.

  - `BeforeID param.Field[string]`

    ID of the object to use as a cursor for pagination. When provided, returns the page of results immediately before this object.

  - `Limit param.Field[int64]`

    Number of items to return per page.

    Defaults to `20`. Ranges from `1` to `1000`.

### Returns

- `type MessageBatch struct{…}`

  - `ID string`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `ArchivedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  - `CancelInitiatedAt Time`

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  - `CreatedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  - `EndedAt Time`

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  - `ExpiresAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  - `ProcessingStatus MessageBatchProcessingStatus`

    Processing status of the Message Batch.

    - `const MessageBatchProcessingStatusInProgress MessageBatchProcessingStatus = "in_progress"`

    - `const MessageBatchProcessingStatusCanceling MessageBatchProcessingStatus = "canceling"`

    - `const MessageBatchProcessingStatusEnded MessageBatchProcessingStatus = "ended"`

  - `RequestCounts MessageBatchRequestCounts`

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as `processing` and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    - `Canceled int64`

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    - `Errored int64`

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    - `Expired int64`

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    - `Processing int64`

      Number of requests in the Message Batch that are processing.

    - `Succeeded int64`

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  - `ResultsURL string`

    URL to a `.jsonl` file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the `custom_id` field to match results to requests.

  - `Type MessageBatch`

    Object type.

    For Message Batches, this is always `"message_batch"`.

    - `const MessageBatchMessageBatch MessageBatch = "message_batch"`

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/anthropics/anthropic-sdk-go"
  "github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
  client := anthropic.NewClient(
    option.WithAPIKey("my-anthropic-api-key"),
  )
  page, err := client.Messages.Batches.List(context.TODO(), anthropic.MessageBatchListParams{

  })
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", page)
}
```

#### Response

```json
{
  "data": [
    {
      "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
      "archived_at": "2024-08-20T18:37:24.100435Z",
      "cancel_initiated_at": "2024-08-20T18:37:24.100435Z",
      "created_at": "2024-08-20T18:37:24.100435Z",
      "ended_at": "2024-08-20T18:37:24.100435Z",
      "expires_at": "2024-08-20T18:37:24.100435Z",
      "processing_status": "in_progress",
      "request_counts": {
        "canceled": 10,
        "errored": 30,
        "expired": 10,
        "processing": 100,
        "succeeded": 50
      },
      "results_url": "https://api.anthropic.com/v1/messages/batches/msgbatch_013Zva2CMHLNnXjNJJKqJ2EF/results",
      "type": "message_batch"
    }
  ],
  "first_id": "first_id",
  "has_more": true,
  "last_id": "last_id"
}
```

## Cancel a Message Batch

`client.Messages.Batches.Cancel(ctx, messageBatchID) (*MessageBatch, error)`

**post** `/v1/messages/batches/{message_batch_id}/cancel`

Batches may be canceled any time before processing ends. Once cancellation is initiated, the batch enters a `canceling` state, at which time the system may complete any in-progress, non-interruptible requests before finalizing cancellation.

The number of canceled requests is specified in `request_counts`. To determine which requests were canceled, check the individual results within the batch. Note that cancellation may not result in any canceled requests if they were non-interruptible.

Learn more about the Message Batches API in our [user guide](https://docs.claude.com/en/docs/build-with-claude/batch-processing)

### Parameters

- `messageBatchID string`

  ID of the Message Batch.

### Returns

- `type MessageBatch struct{…}`

  - `ID string`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `ArchivedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  - `CancelInitiatedAt Time`

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  - `CreatedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  - `EndedAt Time`

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  - `ExpiresAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  - `ProcessingStatus MessageBatchProcessingStatus`

    Processing status of the Message Batch.

    - `const MessageBatchProcessingStatusInProgress MessageBatchProcessingStatus = "in_progress"`

    - `const MessageBatchProcessingStatusCanceling MessageBatchProcessingStatus = "canceling"`

    - `const MessageBatchProcessingStatusEnded MessageBatchProcessingStatus = "ended"`

  - `RequestCounts MessageBatchRequestCounts`

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as `processing` and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    - `Canceled int64`

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    - `Errored int64`

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    - `Expired int64`

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    - `Processing int64`

      Number of requests in the Message Batch that are processing.

    - `Succeeded int64`

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  - `ResultsURL string`

    URL to a `.jsonl` file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the `custom_id` field to match results to requests.

  - `Type MessageBatch`

    Object type.

    For Message Batches, this is always `"message_batch"`.

    - `const MessageBatchMessageBatch MessageBatch = "message_batch"`

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/anthropics/anthropic-sdk-go"
  "github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
  client := anthropic.NewClient(
    option.WithAPIKey("my-anthropic-api-key"),
  )
  messageBatch, err := client.Messages.Batches.Cancel(context.TODO(), "message_batch_id")
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", messageBatch.ID)
}
```

#### Response

```json
{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "archived_at": "2024-08-20T18:37:24.100435Z",
  "cancel_initiated_at": "2024-08-20T18:37:24.100435Z",
  "created_at": "2024-08-20T18:37:24.100435Z",
  "ended_at": "2024-08-20T18:37:24.100435Z",
  "expires_at": "2024-08-20T18:37:24.100435Z",
  "processing_status": "in_progress",
  "request_counts": {
    "canceled": 10,
    "errored": 30,
    "expired": 10,
    "processing": 100,
    "succeeded": 50
  },
  "results_url": "https://api.anthropic.com/v1/messages/batches/msgbatch_013Zva2CMHLNnXjNJJKqJ2EF/results",
  "type": "message_batch"
}
```

## Delete a Message Batch

`client.Messages.Batches.Delete(ctx, messageBatchID) (*DeletedMessageBatch, error)`

**delete** `/v1/messages/batches/{message_batch_id}`

Delete a Message Batch.

Message Batches can only be deleted once they've finished processing. If you'd like to delete an in-progress batch, you must first cancel it.

Learn more about the Message Batches API in our [user guide](https://docs.claude.com/en/docs/build-with-claude/batch-processing)

### Parameters

- `messageBatchID string`

  ID of the Message Batch.

### Returns

- `type DeletedMessageBatch struct{…}`

  - `ID string`

    ID of the Message Batch.

  - `Type MessageBatchDeleted`

    Deleted object type.

    For Message Batches, this is always `"message_batch_deleted"`.

    - `const MessageBatchDeletedMessageBatchDeleted MessageBatchDeleted = "message_batch_deleted"`

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/anthropics/anthropic-sdk-go"
  "github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
  client := anthropic.NewClient(
    option.WithAPIKey("my-anthropic-api-key"),
  )
  deletedMessageBatch, err := client.Messages.Batches.Delete(context.TODO(), "message_batch_id")
  if err != nil {
    panic(err.Error())
  }
  fmt.Printf("%+v\n", deletedMessageBatch.ID)
}
```

#### Response

```json
{
  "id": "msgbatch_013Zva2CMHLNnXjNJJKqJ2EF",
  "type": "message_batch_deleted"
}
```

## Retrieve Message Batch results

`client.Messages.Batches.Results(ctx, messageBatchID) (*MessageBatchIndividualResponse, error)`

**get** `/v1/messages/batches/{message_batch_id}/results`

Streams the results of a Message Batch as a `.jsonl` file.

Each line in the file is a JSON object containing the result of a single request in the Message Batch. Results are not guaranteed to be in the same order as requests. Use the `custom_id` field to match results to requests.

Learn more about the Message Batches API in our [user guide](https://docs.claude.com/en/docs/build-with-claude/batch-processing)

### Parameters

- `messageBatchID string`

  ID of the Message Batch.

### Returns

- `type MessageBatchIndividualResponse struct{…}`

  This is a single line in the response `.jsonl` file and does not represent the response as a whole.

  - `CustomID string`

    Developer-provided ID created for each request in a Message Batch. Useful for matching results to requests, as results may be given out of request order.

    Must be unique for each request within the Message Batch.

  - `Result MessageBatchResultUnion`

    Processing result for this request.

    Contains a Message output if processing was successful, an error response if processing failed, or the reason why processing was not attempted, such as cancellation or expiration.

    - `type MessageBatchSucceededResult struct{…}`

      - `Message Message`

        - `ID string`

          Unique object identifier.

          The format and length of IDs may change over time.

        - `Container Container`

          Information about the container used in the request (for the code execution tool)

          - `ID string`

            Identifier for the container used in this request

          - `ExpiresAt Time`

            The time at which the container will expire.

        - `Content []ContentBlockUnion`

          Content generated by the model.

          This is an array of content blocks, each of which has a `type` that determines its shape.

          Example:

          ```json
          [{"type": "text", "text": "Hi, I'm Claude."}]
          ```

          If the request input `messages` ended with an `assistant` turn, then the response `content` will continue directly from that last turn. You can use this to constrain the model's output.

          For example, if the input `messages` were:

          ```json
          [
            {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
            {"role": "assistant", "content": "The best answer is ("}
          ]
          ```

          Then the response `content` might be:

          ```json
          [{"type": "text", "text": "B)"}]
          ```

          - `type TextBlock struct{…}`

            - `Citations []TextCitationUnion`

              Citations supporting the text block.

              The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

              - `type CitationCharLocation struct{…}`

                - `CitedText string`

                - `DocumentIndex int64`

                - `DocumentTitle string`

                - `EndCharIndex int64`

                - `FileID string`

                - `StartCharIndex int64`

                - `Type CharLocation`

                  - `const CharLocationCharLocation CharLocation = "char_location"`

              - `type CitationPageLocation struct{…}`

                - `CitedText string`

                - `DocumentIndex int64`

                - `DocumentTitle string`

                - `EndPageNumber int64`

                - `FileID string`

                - `StartPageNumber int64`

                - `Type PageLocation`

                  - `const PageLocationPageLocation PageLocation = "page_location"`

              - `type CitationContentBlockLocation struct{…}`

                - `CitedText string`

                  The full text of the cited block range, concatenated.

                  Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                - `DocumentIndex int64`

                - `DocumentTitle string`

                - `EndBlockIndex int64`

                  Exclusive 0-based end index of the cited block range in the source's `content` array.

                  Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                - `FileID string`

                - `StartBlockIndex int64`

                  0-based index of the first cited block in the source's `content` array.

                - `Type ContentBlockLocation`

                  - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

              - `type CitationsWebSearchResultLocation struct{…}`

                - `CitedText string`

                - `EncryptedIndex string`

                - `Title string`

                - `Type WebSearchResultLocation`

                  - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

                - `URL string`

              - `type CitationsSearchResultLocation struct{…}`

                - `CitedText string`

                  The full text of the cited block range, concatenated.

                  Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                - `EndBlockIndex int64`

                  Exclusive 0-based end index of the cited block range in the source's `content` array.

                  Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                - `SearchResultIndex int64`

                  0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                  Counted separately from `document_index`; server-side web search results are not included in this count.

                - `Source string`

                - `StartBlockIndex int64`

                  0-based index of the first cited block in the source's `content` array.

                - `Title string`

                - `Type SearchResultLocation`

                  - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

            - `Text string`

            - `Type Text`

              - `const TextText Text = "text"`

          - `type ThinkingBlock struct{…}`

            - `Signature string`

            - `Thinking string`

            - `Type Thinking`

              - `const ThinkingThinking Thinking = "thinking"`

          - `type RedactedThinkingBlock struct{…}`

            - `Data string`

            - `Type RedactedThinking`

              - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

          - `type ToolUseBlock struct{…}`

            - `ID string`

            - `Caller ToolUseBlockCallerUnion`

              Tool invocation directly from the model.

              - `type DirectCaller struct{…}`

                Tool invocation directly from the model.

                - `Type Direct`

                  - `const DirectDirect Direct = "direct"`

              - `type ServerToolCaller struct{…}`

                Tool invocation generated by a server-side tool.

                - `ToolID string`

                - `Type CodeExecution20250825`

                  - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

              - `type ServerToolCaller20260120 struct{…}`

                - `ToolID string`

                - `Type CodeExecution20260120`

                  - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

            - `Input map[string, any]`

            - `Name string`

            - `Type ToolUse`

              - `const ToolUseToolUse ToolUse = "tool_use"`

          - `type ServerToolUseBlock struct{…}`

            - `ID string`

            - `Caller ServerToolUseBlockCallerUnion`

              Tool invocation directly from the model.

              - `type DirectCaller struct{…}`

                Tool invocation directly from the model.

              - `type ServerToolCaller struct{…}`

                Tool invocation generated by a server-side tool.

              - `type ServerToolCaller20260120 struct{…}`

            - `Input map[string, any]`

            - `Name ServerToolUseBlockName`

              - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

              - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

              - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

              - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

              - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

              - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

              - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

            - `Type ServerToolUse`

              - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

          - `type WebSearchToolResultBlock struct{…}`

            - `Caller WebSearchToolResultBlockCallerUnion`

              Tool invocation directly from the model.

              - `type DirectCaller struct{…}`

                Tool invocation directly from the model.

              - `type ServerToolCaller struct{…}`

                Tool invocation generated by a server-side tool.

              - `type ServerToolCaller20260120 struct{…}`

            - `Content WebSearchToolResultBlockContentUnion`

              - `type WebSearchToolResultError struct{…}`

                - `ErrorCode WebSearchToolResultErrorCode`

                  - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

                  - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

                  - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

                  - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

                  - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

                  - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

                - `Type WebSearchToolResultError`

                  - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

              - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

                - `EncryptedContent string`

                - `PageAge string`

                - `Title string`

                - `Type WebSearchResult`

                  - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

                - `URL string`

            - `ToolUseID string`

            - `Type WebSearchToolResult`

              - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

          - `type WebFetchToolResultBlock struct{…}`

            - `Caller WebFetchToolResultBlockCallerUnion`

              Tool invocation directly from the model.

              - `type DirectCaller struct{…}`

                Tool invocation directly from the model.

              - `type ServerToolCaller struct{…}`

                Tool invocation generated by a server-side tool.

              - `type ServerToolCaller20260120 struct{…}`

            - `Content WebFetchToolResultBlockContentUnion`

              - `type WebFetchToolResultErrorBlock struct{…}`

                - `ErrorCode WebFetchToolResultErrorCode`

                  - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

                  - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

                  - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

                  - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

                  - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

                  - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

                  - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

                  - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

                  - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

                - `Type WebFetchToolResultError`

                  - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

              - `type WebFetchBlock struct{…}`

                - `Content DocumentBlock`

                  - `Citations CitationsConfig`

                    Citation configuration for the document

                    - `Enabled bool`

                  - `Source DocumentBlockSourceUnion`

                    - `type Base64PDFSource struct{…}`

                      - `Data string`

                      - `MediaType ApplicationPDF`

                        - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                      - `Type Base64`

                        - `const Base64Base64 Base64 = "base64"`

                    - `type PlainTextSource struct{…}`

                      - `Data string`

                      - `MediaType TextPlain`

                        - `const TextPlainTextPlain TextPlain = "text/plain"`

                      - `Type Text`

                        - `const TextText Text = "text"`

                  - `Title string`

                    The title of the document

                  - `Type Document`

                    - `const DocumentDocument Document = "document"`

                - `RetrievedAt string`

                  ISO 8601 timestamp when the content was retrieved

                - `Type WebFetchResult`

                  - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

                - `URL string`

                  Fetched content URL

            - `ToolUseID string`

            - `Type WebFetchToolResult`

              - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

          - `type CodeExecutionToolResultBlock struct{…}`

            - `Content CodeExecutionToolResultBlockContentUnion`

              Code execution result with encrypted stdout for PFC + web_search results.

              - `type CodeExecutionToolResultError struct{…}`

                - `ErrorCode CodeExecutionToolResultErrorCode`

                  - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

                  - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

                  - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

                  - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `Type CodeExecutionToolResultError`

                  - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

              - `type CodeExecutionResultBlock struct{…}`

                - `Content []CodeExecutionOutputBlock`

                  - `FileID string`

                  - `Type CodeExecutionOutput`

                    - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

                - `ReturnCode int64`

                - `Stderr string`

                - `Stdout string`

                - `Type CodeExecutionResult`

                  - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

              - `type EncryptedCodeExecutionResultBlock struct{…}`

                Code execution result with encrypted stdout for PFC + web_search results.

                - `Content []CodeExecutionOutputBlock`

                  - `FileID string`

                  - `Type CodeExecutionOutput`

                - `EncryptedStdout string`

                - `ReturnCode int64`

                - `Stderr string`

                - `Type EncryptedCodeExecutionResult`

                  - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

            - `ToolUseID string`

            - `Type CodeExecutionToolResult`

              - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

          - `type BashCodeExecutionToolResultBlock struct{…}`

            - `Content BashCodeExecutionToolResultBlockContentUnion`

              - `type BashCodeExecutionToolResultError struct{…}`

                - `ErrorCode BashCodeExecutionToolResultErrorCode`

                  - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                  - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

                  - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

                  - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                  - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

                - `Type BashCodeExecutionToolResultError`

                  - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

              - `type BashCodeExecutionResultBlock struct{…}`

                - `Content []BashCodeExecutionOutputBlock`

                  - `FileID string`

                  - `Type BashCodeExecutionOutput`

                    - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

                - `ReturnCode int64`

                - `Stderr string`

                - `Stdout string`

                - `Type BashCodeExecutionResult`

                  - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

            - `ToolUseID string`

            - `Type BashCodeExecutionToolResult`

              - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

          - `type TextEditorCodeExecutionToolResultBlock struct{…}`

            - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

              - `type TextEditorCodeExecutionToolResultError struct{…}`

                - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

                  - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                  - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

                  - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

                  - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                  - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

                - `ErrorMessage string`

                - `Type TextEditorCodeExecutionToolResultError`

                  - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

              - `type TextEditorCodeExecutionViewResultBlock struct{…}`

                - `Content string`

                - `FileType TextEditorCodeExecutionViewResultBlockFileType`

                  - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

                  - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

                  - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

                - `NumLines int64`

                - `StartLine int64`

                - `TotalLines int64`

                - `Type TextEditorCodeExecutionViewResult`

                  - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

              - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

                - `IsFileUpdate bool`

                - `Type TextEditorCodeExecutionCreateResult`

                  - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

              - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

                - `Lines []string`

                - `NewLines int64`

                - `NewStart int64`

                - `OldLines int64`

                - `OldStart int64`

                - `Type TextEditorCodeExecutionStrReplaceResult`

                  - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

            - `ToolUseID string`

            - `Type TextEditorCodeExecutionToolResult`

              - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

          - `type ToolSearchToolResultBlock struct{…}`

            - `Content ToolSearchToolResultBlockContentUnion`

              - `type ToolSearchToolResultError struct{…}`

                - `ErrorCode ToolSearchToolResultErrorCode`

                  - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

                  - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

                  - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

                  - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

                - `ErrorMessage string`

                - `Type ToolSearchToolResultError`

                  - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

              - `type ToolSearchToolSearchResultBlock struct{…}`

                - `ToolReferences []ToolReferenceBlock`

                  - `ToolName string`

                  - `Type ToolReference`

                    - `const ToolReferenceToolReference ToolReference = "tool_reference"`

                - `Type ToolSearchToolSearchResult`

                  - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

            - `ToolUseID string`

            - `Type ToolSearchToolResult`

              - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

          - `type ContainerUploadBlock struct{…}`

            Response model for a file uploaded to the container.

            - `FileID string`

            - `Type ContainerUpload`

              - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

        - `Model Model`

          The model that will complete your prompt.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `type Model string`

            The model that will complete your prompt.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `const ModelClaudeFable5 Model = "claude-fable-5"`

              Next generation of intelligence for the hardest knowledge work and coding problems

            - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

              Most capable model for cybersecurity and biology research

            - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

              Frontier intelligence for long-running agents and coding

            - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

              Frontier intelligence for long-running agents and coding

            - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

              New class of intelligence, strongest in coding and cybersecurity

            - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

              Frontier intelligence for long-running agents and coding

            - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

              Best combination of speed and intelligence

            - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

              Fastest model with near-frontier intelligence

            - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

              Fastest model with near-frontier intelligence

            - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

              Premium model combining maximum intelligence with practical performance

            - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

              Premium model combining maximum intelligence with practical performance

            - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

              High-performance model for agents and coding

            - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

              High-performance model for agents and coding

            - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

              Exceptional model for specialized complex tasks

            - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

              Exceptional model for specialized complex tasks

            - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

              Powerful model for complex tasks

            - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

              Powerful model for complex tasks

            - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

              High-performance model with extended thinking

            - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

              High-performance model with extended thinking

            - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

              Fast and cost-effective model

          - `string`

        - `Role Assistant`

          Conversational role of the generated message.

          This will always be `"assistant"`.

          - `const AssistantAssistant Assistant = "assistant"`

        - `StopDetails RefusalStopDetails`

          Structured information about a refusal.

          - `Category RefusalStopDetailsCategory`

            The policy category that triggered the refusal.

            `null` when the refusal doesn't map to a named category.

            - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

            - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

            - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

          - `Explanation string`

            Human-readable explanation of the refusal.

            This text is not guaranteed to be stable. `null` when no explanation is available for the category.

          - `Type Refusal`

            - `const RefusalRefusal Refusal = "refusal"`

        - `StopReason StopReason`

          The reason that we stopped.

          This may be one the following values:

          * `"end_turn"`: the model reached a natural stopping point
          * `"max_tokens"`: we exceeded the requested `max_tokens` or the model's maximum
          * `"stop_sequence"`: one of your provided custom `stop_sequences` was generated
          * `"tool_use"`: the model invoked one or more tools
          * `"pause_turn"`: we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
          * `"refusal"`: when streaming classifiers intervene to handle potential policy violations

          In non-streaming mode this value is always non-null. In streaming mode, it is null in the `message_start` event and non-null otherwise.

          - `const StopReasonEndTurn StopReason = "end_turn"`

          - `const StopReasonMaxTokens StopReason = "max_tokens"`

          - `const StopReasonStopSequence StopReason = "stop_sequence"`

          - `const StopReasonToolUse StopReason = "tool_use"`

          - `const StopReasonPauseTurn StopReason = "pause_turn"`

          - `const StopReasonRefusal StopReason = "refusal"`

        - `StopSequence string`

          Which custom stop sequence was generated, if any.

          This value will be a non-null string if one of your custom stop sequences was generated.

        - `Type Message`

          Object type.

          For Messages, this is always `"message"`.

          - `const MessageMessage Message = "message"`

        - `Usage Usage`

          Billing and rate-limit usage.

          Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

          Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

          For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

          Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

          - `CacheCreation CacheCreation`

            Breakdown of cached tokens by TTL

            - `Ephemeral1hInputTokens int64`

              The number of input tokens used to create the 1 hour cache entry.

            - `Ephemeral5mInputTokens int64`

              The number of input tokens used to create the 5 minute cache entry.

          - `CacheCreationInputTokens int64`

            The number of input tokens used to create the cache entry.

          - `CacheReadInputTokens int64`

            The number of input tokens read from the cache.

          - `InferenceGeo string`

            The geographic region where inference was performed for this request.

          - `InputTokens int64`

            The number of input tokens which were used.

          - `OutputTokens int64`

            The number of output tokens which were used.

          - `OutputTokensDetails OutputTokensDetails`

            Breakdown of output tokens by category.

            `output_tokens` remains the inclusive, authoritative total used for billing.
            This object provides a read-only decomposition for observability — for example,
            how many of the billed output tokens were spent on internal reasoning that may
            have been summarized before being returned to you.

            - `ThinkingTokens int64`

              Number of output tokens the model generated as internal reasoning, including
              the thinking-block delimiter tokens.

              Reflects the raw reasoning the model produced, not the (possibly shorter)
              summarized thinking text returned in the response body. Computed by
              re-tokenizing the raw reasoning text, so it may differ from the model's exact
              generation count by a small number of tokens. Always ≤ `output_tokens`;
              `output_tokens - thinking_tokens` approximates the non-reasoning output.

          - `ServerToolUse ServerToolUsage`

            The number of server tool requests.

            - `WebFetchRequests int64`

              The number of web fetch tool requests.

            - `WebSearchRequests int64`

              The number of web search tool requests.

          - `ServiceTier UsageServiceTier`

            If the request used the priority, standard, or batch tier.

            - `const UsageServiceTierStandard UsageServiceTier = "standard"`

            - `const UsageServiceTierPriority UsageServiceTier = "priority"`

            - `const UsageServiceTierBatch UsageServiceTier = "batch"`

      - `Type Succeeded`

        - `const SucceededSucceeded Succeeded = "succeeded"`

    - `type MessageBatchErroredResult struct{…}`

      - `Error ErrorResponse`

        - `Error ErrorObjectUnion`

          - `type InvalidRequestError struct{…}`

            - `Message string`

            - `Type InvalidRequestError`

              - `const InvalidRequestErrorInvalidRequestError InvalidRequestError = "invalid_request_error"`

          - `type AuthenticationError struct{…}`

            - `Message string`

            - `Type AuthenticationError`

              - `const AuthenticationErrorAuthenticationError AuthenticationError = "authentication_error"`

          - `type BillingError struct{…}`

            - `Message string`

            - `Type BillingError`

              - `const BillingErrorBillingError BillingError = "billing_error"`

          - `type PermissionError struct{…}`

            - `Message string`

            - `Type PermissionError`

              - `const PermissionErrorPermissionError PermissionError = "permission_error"`

          - `type NotFoundError struct{…}`

            - `Message string`

            - `Type NotFoundError`

              - `const NotFoundErrorNotFoundError NotFoundError = "not_found_error"`

          - `type RateLimitError struct{…}`

            - `Message string`

            - `Type RateLimitError`

              - `const RateLimitErrorRateLimitError RateLimitError = "rate_limit_error"`

          - `type GatewayTimeoutError struct{…}`

            - `Message string`

            - `Type TimeoutError`

              - `const TimeoutErrorTimeoutError TimeoutError = "timeout_error"`

          - `type APIErrorObject struct{…}`

            - `Message string`

            - `Type APIError`

              - `const APIErrorAPIError APIError = "api_error"`

          - `type OverloadedError struct{…}`

            - `Message string`

            - `Type OverloadedError`

              - `const OverloadedErrorOverloadedError OverloadedError = "overloaded_error"`

        - `RequestID string`

        - `Type Error`

          - `const ErrorError Error = "error"`

      - `Type Errored`

        - `const ErroredErrored Errored = "errored"`

    - `type MessageBatchCanceledResult struct{…}`

      - `Type Canceled`

        - `const CanceledCanceled Canceled = "canceled"`

    - `type MessageBatchExpiredResult struct{…}`

      - `Type Expired`

        - `const ExpiredExpired Expired = "expired"`

### Example

```go
package main

import (
  "context"
  "fmt"

  "github.com/anthropics/anthropic-sdk-go"
  "github.com/anthropics/anthropic-sdk-go/option"
)

func main() {
  client := anthropic.NewClient(
    option.WithAPIKey("my-anthropic-api-key"),
  )
  stream := client.Messages.Batches.ResultsStreaming(context.TODO(), "message_batch_id")
  for stream.Next() {
  fmt.Printf("%+v\n", stream.Current())
  }
  err := stream.Err()
  if err != nil {
    panic(err.Error())
  }
}
```

## Domain Types

### Deleted Message Batch

- `type DeletedMessageBatch struct{…}`

  - `ID string`

    ID of the Message Batch.

  - `Type MessageBatchDeleted`

    Deleted object type.

    For Message Batches, this is always `"message_batch_deleted"`.

    - `const MessageBatchDeletedMessageBatchDeleted MessageBatchDeleted = "message_batch_deleted"`

### Message Batch

- `type MessageBatch struct{…}`

  - `ID string`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `ArchivedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was archived and its results became unavailable.

  - `CancelInitiatedAt Time`

    RFC 3339 datetime string representing the time at which cancellation was initiated for the Message Batch. Specified only if cancellation was initiated.

  - `CreatedAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch was created.

  - `EndedAt Time`

    RFC 3339 datetime string representing the time at which processing for the Message Batch ended. Specified only once processing ends.

    Processing ends when every request in a Message Batch has either succeeded, errored, canceled, or expired.

  - `ExpiresAt Time`

    RFC 3339 datetime string representing the time at which the Message Batch will expire and end processing, which is 24 hours after creation.

  - `ProcessingStatus MessageBatchProcessingStatus`

    Processing status of the Message Batch.

    - `const MessageBatchProcessingStatusInProgress MessageBatchProcessingStatus = "in_progress"`

    - `const MessageBatchProcessingStatusCanceling MessageBatchProcessingStatus = "canceling"`

    - `const MessageBatchProcessingStatusEnded MessageBatchProcessingStatus = "ended"`

  - `RequestCounts MessageBatchRequestCounts`

    Tallies requests within the Message Batch, categorized by their status.

    Requests start as `processing` and move to one of the other statuses only once processing of the entire batch ends. The sum of all values always matches the total number of requests in the batch.

    - `Canceled int64`

      Number of requests in the Message Batch that have been canceled.

      This is zero until processing of the entire Message Batch has ended.

    - `Errored int64`

      Number of requests in the Message Batch that encountered an error.

      This is zero until processing of the entire Message Batch has ended.

    - `Expired int64`

      Number of requests in the Message Batch that have expired.

      This is zero until processing of the entire Message Batch has ended.

    - `Processing int64`

      Number of requests in the Message Batch that are processing.

    - `Succeeded int64`

      Number of requests in the Message Batch that have completed successfully.

      This is zero until processing of the entire Message Batch has ended.

  - `ResultsURL string`

    URL to a `.jsonl` file containing the results of the Message Batch requests. Specified only once processing ends.

    Results in the file are not guaranteed to be in the same order as requests. Use the `custom_id` field to match results to requests.

  - `Type MessageBatch`

    Object type.

    For Message Batches, this is always `"message_batch"`.

    - `const MessageBatchMessageBatch MessageBatch = "message_batch"`

### Message Batch Canceled Result

- `type MessageBatchCanceledResult struct{…}`

  - `Type Canceled`

    - `const CanceledCanceled Canceled = "canceled"`

### Message Batch Errored Result

- `type MessageBatchErroredResult struct{…}`

  - `Error ErrorResponse`

    - `Error ErrorObjectUnion`

      - `type InvalidRequestError struct{…}`

        - `Message string`

        - `Type InvalidRequestError`

          - `const InvalidRequestErrorInvalidRequestError InvalidRequestError = "invalid_request_error"`

      - `type AuthenticationError struct{…}`

        - `Message string`

        - `Type AuthenticationError`

          - `const AuthenticationErrorAuthenticationError AuthenticationError = "authentication_error"`

      - `type BillingError struct{…}`

        - `Message string`

        - `Type BillingError`

          - `const BillingErrorBillingError BillingError = "billing_error"`

      - `type PermissionError struct{…}`

        - `Message string`

        - `Type PermissionError`

          - `const PermissionErrorPermissionError PermissionError = "permission_error"`

      - `type NotFoundError struct{…}`

        - `Message string`

        - `Type NotFoundError`

          - `const NotFoundErrorNotFoundError NotFoundError = "not_found_error"`

      - `type RateLimitError struct{…}`

        - `Message string`

        - `Type RateLimitError`

          - `const RateLimitErrorRateLimitError RateLimitError = "rate_limit_error"`

      - `type GatewayTimeoutError struct{…}`

        - `Message string`

        - `Type TimeoutError`

          - `const TimeoutErrorTimeoutError TimeoutError = "timeout_error"`

      - `type APIErrorObject struct{…}`

        - `Message string`

        - `Type APIError`

          - `const APIErrorAPIError APIError = "api_error"`

      - `type OverloadedError struct{…}`

        - `Message string`

        - `Type OverloadedError`

          - `const OverloadedErrorOverloadedError OverloadedError = "overloaded_error"`

    - `RequestID string`

    - `Type Error`

      - `const ErrorError Error = "error"`

  - `Type Errored`

    - `const ErroredErrored Errored = "errored"`

### Message Batch Expired Result

- `type MessageBatchExpiredResult struct{…}`

  - `Type Expired`

    - `const ExpiredExpired Expired = "expired"`

### Message Batch Individual Response

- `type MessageBatchIndividualResponse struct{…}`

  This is a single line in the response `.jsonl` file and does not represent the response as a whole.

  - `CustomID string`

    Developer-provided ID created for each request in a Message Batch. Useful for matching results to requests, as results may be given out of request order.

    Must be unique for each request within the Message Batch.

  - `Result MessageBatchResultUnion`

    Processing result for this request.

    Contains a Message output if processing was successful, an error response if processing failed, or the reason why processing was not attempted, such as cancellation or expiration.

    - `type MessageBatchSucceededResult struct{…}`

      - `Message Message`

        - `ID string`

          Unique object identifier.

          The format and length of IDs may change over time.

        - `Container Container`

          Information about the container used in the request (for the code execution tool)

          - `ID string`

            Identifier for the container used in this request

          - `ExpiresAt Time`

            The time at which the container will expire.

        - `Content []ContentBlockUnion`

          Content generated by the model.

          This is an array of content blocks, each of which has a `type` that determines its shape.

          Example:

          ```json
          [{"type": "text", "text": "Hi, I'm Claude."}]
          ```

          If the request input `messages` ended with an `assistant` turn, then the response `content` will continue directly from that last turn. You can use this to constrain the model's output.

          For example, if the input `messages` were:

          ```json
          [
            {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
            {"role": "assistant", "content": "The best answer is ("}
          ]
          ```

          Then the response `content` might be:

          ```json
          [{"type": "text", "text": "B)"}]
          ```

          - `type TextBlock struct{…}`

            - `Citations []TextCitationUnion`

              Citations supporting the text block.

              The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

              - `type CitationCharLocation struct{…}`

                - `CitedText string`

                - `DocumentIndex int64`

                - `DocumentTitle string`

                - `EndCharIndex int64`

                - `FileID string`

                - `StartCharIndex int64`

                - `Type CharLocation`

                  - `const CharLocationCharLocation CharLocation = "char_location"`

              - `type CitationPageLocation struct{…}`

                - `CitedText string`

                - `DocumentIndex int64`

                - `DocumentTitle string`

                - `EndPageNumber int64`

                - `FileID string`

                - `StartPageNumber int64`

                - `Type PageLocation`

                  - `const PageLocationPageLocation PageLocation = "page_location"`

              - `type CitationContentBlockLocation struct{…}`

                - `CitedText string`

                  The full text of the cited block range, concatenated.

                  Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                - `DocumentIndex int64`

                - `DocumentTitle string`

                - `EndBlockIndex int64`

                  Exclusive 0-based end index of the cited block range in the source's `content` array.

                  Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                - `FileID string`

                - `StartBlockIndex int64`

                  0-based index of the first cited block in the source's `content` array.

                - `Type ContentBlockLocation`

                  - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

              - `type CitationsWebSearchResultLocation struct{…}`

                - `CitedText string`

                - `EncryptedIndex string`

                - `Title string`

                - `Type WebSearchResultLocation`

                  - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

                - `URL string`

              - `type CitationsSearchResultLocation struct{…}`

                - `CitedText string`

                  The full text of the cited block range, concatenated.

                  Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

                - `EndBlockIndex int64`

                  Exclusive 0-based end index of the cited block range in the source's `content` array.

                  Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

                - `SearchResultIndex int64`

                  0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                  Counted separately from `document_index`; server-side web search results are not included in this count.

                - `Source string`

                - `StartBlockIndex int64`

                  0-based index of the first cited block in the source's `content` array.

                - `Title string`

                - `Type SearchResultLocation`

                  - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

            - `Text string`

            - `Type Text`

              - `const TextText Text = "text"`

          - `type ThinkingBlock struct{…}`

            - `Signature string`

            - `Thinking string`

            - `Type Thinking`

              - `const ThinkingThinking Thinking = "thinking"`

          - `type RedactedThinkingBlock struct{…}`

            - `Data string`

            - `Type RedactedThinking`

              - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

          - `type ToolUseBlock struct{…}`

            - `ID string`

            - `Caller ToolUseBlockCallerUnion`

              Tool invocation directly from the model.

              - `type DirectCaller struct{…}`

                Tool invocation directly from the model.

                - `Type Direct`

                  - `const DirectDirect Direct = "direct"`

              - `type ServerToolCaller struct{…}`

                Tool invocation generated by a server-side tool.

                - `ToolID string`

                - `Type CodeExecution20250825`

                  - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

              - `type ServerToolCaller20260120 struct{…}`

                - `ToolID string`

                - `Type CodeExecution20260120`

                  - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

            - `Input map[string, any]`

            - `Name string`

            - `Type ToolUse`

              - `const ToolUseToolUse ToolUse = "tool_use"`

          - `type ServerToolUseBlock struct{…}`

            - `ID string`

            - `Caller ServerToolUseBlockCallerUnion`

              Tool invocation directly from the model.

              - `type DirectCaller struct{…}`

                Tool invocation directly from the model.

              - `type ServerToolCaller struct{…}`

                Tool invocation generated by a server-side tool.

              - `type ServerToolCaller20260120 struct{…}`

            - `Input map[string, any]`

            - `Name ServerToolUseBlockName`

              - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

              - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

              - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

              - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

              - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

              - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

              - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

            - `Type ServerToolUse`

              - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

          - `type WebSearchToolResultBlock struct{…}`

            - `Caller WebSearchToolResultBlockCallerUnion`

              Tool invocation directly from the model.

              - `type DirectCaller struct{…}`

                Tool invocation directly from the model.

              - `type ServerToolCaller struct{…}`

                Tool invocation generated by a server-side tool.

              - `type ServerToolCaller20260120 struct{…}`

            - `Content WebSearchToolResultBlockContentUnion`

              - `type WebSearchToolResultError struct{…}`

                - `ErrorCode WebSearchToolResultErrorCode`

                  - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

                  - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

                  - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

                  - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

                  - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

                  - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

                - `Type WebSearchToolResultError`

                  - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

              - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

                - `EncryptedContent string`

                - `PageAge string`

                - `Title string`

                - `Type WebSearchResult`

                  - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

                - `URL string`

            - `ToolUseID string`

            - `Type WebSearchToolResult`

              - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

          - `type WebFetchToolResultBlock struct{…}`

            - `Caller WebFetchToolResultBlockCallerUnion`

              Tool invocation directly from the model.

              - `type DirectCaller struct{…}`

                Tool invocation directly from the model.

              - `type ServerToolCaller struct{…}`

                Tool invocation generated by a server-side tool.

              - `type ServerToolCaller20260120 struct{…}`

            - `Content WebFetchToolResultBlockContentUnion`

              - `type WebFetchToolResultErrorBlock struct{…}`

                - `ErrorCode WebFetchToolResultErrorCode`

                  - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

                  - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

                  - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

                  - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

                  - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

                  - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

                  - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

                  - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

                  - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

                - `Type WebFetchToolResultError`

                  - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

              - `type WebFetchBlock struct{…}`

                - `Content DocumentBlock`

                  - `Citations CitationsConfig`

                    Citation configuration for the document

                    - `Enabled bool`

                  - `Source DocumentBlockSourceUnion`

                    - `type Base64PDFSource struct{…}`

                      - `Data string`

                      - `MediaType ApplicationPDF`

                        - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                      - `Type Base64`

                        - `const Base64Base64 Base64 = "base64"`

                    - `type PlainTextSource struct{…}`

                      - `Data string`

                      - `MediaType TextPlain`

                        - `const TextPlainTextPlain TextPlain = "text/plain"`

                      - `Type Text`

                        - `const TextText Text = "text"`

                  - `Title string`

                    The title of the document

                  - `Type Document`

                    - `const DocumentDocument Document = "document"`

                - `RetrievedAt string`

                  ISO 8601 timestamp when the content was retrieved

                - `Type WebFetchResult`

                  - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

                - `URL string`

                  Fetched content URL

            - `ToolUseID string`

            - `Type WebFetchToolResult`

              - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

          - `type CodeExecutionToolResultBlock struct{…}`

            - `Content CodeExecutionToolResultBlockContentUnion`

              Code execution result with encrypted stdout for PFC + web_search results.

              - `type CodeExecutionToolResultError struct{…}`

                - `ErrorCode CodeExecutionToolResultErrorCode`

                  - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

                  - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

                  - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

                  - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `Type CodeExecutionToolResultError`

                  - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

              - `type CodeExecutionResultBlock struct{…}`

                - `Content []CodeExecutionOutputBlock`

                  - `FileID string`

                  - `Type CodeExecutionOutput`

                    - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

                - `ReturnCode int64`

                - `Stderr string`

                - `Stdout string`

                - `Type CodeExecutionResult`

                  - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

              - `type EncryptedCodeExecutionResultBlock struct{…}`

                Code execution result with encrypted stdout for PFC + web_search results.

                - `Content []CodeExecutionOutputBlock`

                  - `FileID string`

                  - `Type CodeExecutionOutput`

                - `EncryptedStdout string`

                - `ReturnCode int64`

                - `Stderr string`

                - `Type EncryptedCodeExecutionResult`

                  - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

            - `ToolUseID string`

            - `Type CodeExecutionToolResult`

              - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

          - `type BashCodeExecutionToolResultBlock struct{…}`

            - `Content BashCodeExecutionToolResultBlockContentUnion`

              - `type BashCodeExecutionToolResultError struct{…}`

                - `ErrorCode BashCodeExecutionToolResultErrorCode`

                  - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                  - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

                  - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

                  - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                  - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

                - `Type BashCodeExecutionToolResultError`

                  - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

              - `type BashCodeExecutionResultBlock struct{…}`

                - `Content []BashCodeExecutionOutputBlock`

                  - `FileID string`

                  - `Type BashCodeExecutionOutput`

                    - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

                - `ReturnCode int64`

                - `Stderr string`

                - `Stdout string`

                - `Type BashCodeExecutionResult`

                  - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

            - `ToolUseID string`

            - `Type BashCodeExecutionToolResult`

              - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

          - `type TextEditorCodeExecutionToolResultBlock struct{…}`

            - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

              - `type TextEditorCodeExecutionToolResultError struct{…}`

                - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

                  - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                  - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

                  - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

                  - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                  - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

                - `ErrorMessage string`

                - `Type TextEditorCodeExecutionToolResultError`

                  - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

              - `type TextEditorCodeExecutionViewResultBlock struct{…}`

                - `Content string`

                - `FileType TextEditorCodeExecutionViewResultBlockFileType`

                  - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

                  - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

                  - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

                - `NumLines int64`

                - `StartLine int64`

                - `TotalLines int64`

                - `Type TextEditorCodeExecutionViewResult`

                  - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

              - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

                - `IsFileUpdate bool`

                - `Type TextEditorCodeExecutionCreateResult`

                  - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

              - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

                - `Lines []string`

                - `NewLines int64`

                - `NewStart int64`

                - `OldLines int64`

                - `OldStart int64`

                - `Type TextEditorCodeExecutionStrReplaceResult`

                  - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

            - `ToolUseID string`

            - `Type TextEditorCodeExecutionToolResult`

              - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

          - `type ToolSearchToolResultBlock struct{…}`

            - `Content ToolSearchToolResultBlockContentUnion`

              - `type ToolSearchToolResultError struct{…}`

                - `ErrorCode ToolSearchToolResultErrorCode`

                  - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

                  - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

                  - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

                  - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

                - `ErrorMessage string`

                - `Type ToolSearchToolResultError`

                  - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

              - `type ToolSearchToolSearchResultBlock struct{…}`

                - `ToolReferences []ToolReferenceBlock`

                  - `ToolName string`

                  - `Type ToolReference`

                    - `const ToolReferenceToolReference ToolReference = "tool_reference"`

                - `Type ToolSearchToolSearchResult`

                  - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

            - `ToolUseID string`

            - `Type ToolSearchToolResult`

              - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

          - `type ContainerUploadBlock struct{…}`

            Response model for a file uploaded to the container.

            - `FileID string`

            - `Type ContainerUpload`

              - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

        - `Model Model`

          The model that will complete your prompt.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `type Model string`

            The model that will complete your prompt.

            See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

            - `const ModelClaudeFable5 Model = "claude-fable-5"`

              Next generation of intelligence for the hardest knowledge work and coding problems

            - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

              Most capable model for cybersecurity and biology research

            - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

              Frontier intelligence for long-running agents and coding

            - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

              Frontier intelligence for long-running agents and coding

            - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

              New class of intelligence, strongest in coding and cybersecurity

            - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

              Frontier intelligence for long-running agents and coding

            - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

              Best combination of speed and intelligence

            - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

              Fastest model with near-frontier intelligence

            - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

              Fastest model with near-frontier intelligence

            - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

              Premium model combining maximum intelligence with practical performance

            - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

              Premium model combining maximum intelligence with practical performance

            - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

              High-performance model for agents and coding

            - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

              High-performance model for agents and coding

            - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

              Exceptional model for specialized complex tasks

            - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

              Exceptional model for specialized complex tasks

            - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

              Powerful model for complex tasks

            - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

              Powerful model for complex tasks

            - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

              High-performance model with extended thinking

            - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

              High-performance model with extended thinking

            - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

              Fast and cost-effective model

          - `string`

        - `Role Assistant`

          Conversational role of the generated message.

          This will always be `"assistant"`.

          - `const AssistantAssistant Assistant = "assistant"`

        - `StopDetails RefusalStopDetails`

          Structured information about a refusal.

          - `Category RefusalStopDetailsCategory`

            The policy category that triggered the refusal.

            `null` when the refusal doesn't map to a named category.

            - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

            - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

            - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

          - `Explanation string`

            Human-readable explanation of the refusal.

            This text is not guaranteed to be stable. `null` when no explanation is available for the category.

          - `Type Refusal`

            - `const RefusalRefusal Refusal = "refusal"`

        - `StopReason StopReason`

          The reason that we stopped.

          This may be one the following values:

          * `"end_turn"`: the model reached a natural stopping point
          * `"max_tokens"`: we exceeded the requested `max_tokens` or the model's maximum
          * `"stop_sequence"`: one of your provided custom `stop_sequences` was generated
          * `"tool_use"`: the model invoked one or more tools
          * `"pause_turn"`: we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
          * `"refusal"`: when streaming classifiers intervene to handle potential policy violations

          In non-streaming mode this value is always non-null. In streaming mode, it is null in the `message_start` event and non-null otherwise.

          - `const StopReasonEndTurn StopReason = "end_turn"`

          - `const StopReasonMaxTokens StopReason = "max_tokens"`

          - `const StopReasonStopSequence StopReason = "stop_sequence"`

          - `const StopReasonToolUse StopReason = "tool_use"`

          - `const StopReasonPauseTurn StopReason = "pause_turn"`

          - `const StopReasonRefusal StopReason = "refusal"`

        - `StopSequence string`

          Which custom stop sequence was generated, if any.

          This value will be a non-null string if one of your custom stop sequences was generated.

        - `Type Message`

          Object type.

          For Messages, this is always `"message"`.

          - `const MessageMessage Message = "message"`

        - `Usage Usage`

          Billing and rate-limit usage.

          Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

          Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

          For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

          Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

          - `CacheCreation CacheCreation`

            Breakdown of cached tokens by TTL

            - `Ephemeral1hInputTokens int64`

              The number of input tokens used to create the 1 hour cache entry.

            - `Ephemeral5mInputTokens int64`

              The number of input tokens used to create the 5 minute cache entry.

          - `CacheCreationInputTokens int64`

            The number of input tokens used to create the cache entry.

          - `CacheReadInputTokens int64`

            The number of input tokens read from the cache.

          - `InferenceGeo string`

            The geographic region where inference was performed for this request.

          - `InputTokens int64`

            The number of input tokens which were used.

          - `OutputTokens int64`

            The number of output tokens which were used.

          - `OutputTokensDetails OutputTokensDetails`

            Breakdown of output tokens by category.

            `output_tokens` remains the inclusive, authoritative total used for billing.
            This object provides a read-only decomposition for observability — for example,
            how many of the billed output tokens were spent on internal reasoning that may
            have been summarized before being returned to you.

            - `ThinkingTokens int64`

              Number of output tokens the model generated as internal reasoning, including
              the thinking-block delimiter tokens.

              Reflects the raw reasoning the model produced, not the (possibly shorter)
              summarized thinking text returned in the response body. Computed by
              re-tokenizing the raw reasoning text, so it may differ from the model's exact
              generation count by a small number of tokens. Always ≤ `output_tokens`;
              `output_tokens - thinking_tokens` approximates the non-reasoning output.

          - `ServerToolUse ServerToolUsage`

            The number of server tool requests.

            - `WebFetchRequests int64`

              The number of web fetch tool requests.

            - `WebSearchRequests int64`

              The number of web search tool requests.

          - `ServiceTier UsageServiceTier`

            If the request used the priority, standard, or batch tier.

            - `const UsageServiceTierStandard UsageServiceTier = "standard"`

            - `const UsageServiceTierPriority UsageServiceTier = "priority"`

            - `const UsageServiceTierBatch UsageServiceTier = "batch"`

      - `Type Succeeded`

        - `const SucceededSucceeded Succeeded = "succeeded"`

    - `type MessageBatchErroredResult struct{…}`

      - `Error ErrorResponse`

        - `Error ErrorObjectUnion`

          - `type InvalidRequestError struct{…}`

            - `Message string`

            - `Type InvalidRequestError`

              - `const InvalidRequestErrorInvalidRequestError InvalidRequestError = "invalid_request_error"`

          - `type AuthenticationError struct{…}`

            - `Message string`

            - `Type AuthenticationError`

              - `const AuthenticationErrorAuthenticationError AuthenticationError = "authentication_error"`

          - `type BillingError struct{…}`

            - `Message string`

            - `Type BillingError`

              - `const BillingErrorBillingError BillingError = "billing_error"`

          - `type PermissionError struct{…}`

            - `Message string`

            - `Type PermissionError`

              - `const PermissionErrorPermissionError PermissionError = "permission_error"`

          - `type NotFoundError struct{…}`

            - `Message string`

            - `Type NotFoundError`

              - `const NotFoundErrorNotFoundError NotFoundError = "not_found_error"`

          - `type RateLimitError struct{…}`

            - `Message string`

            - `Type RateLimitError`

              - `const RateLimitErrorRateLimitError RateLimitError = "rate_limit_error"`

          - `type GatewayTimeoutError struct{…}`

            - `Message string`

            - `Type TimeoutError`

              - `const TimeoutErrorTimeoutError TimeoutError = "timeout_error"`

          - `type APIErrorObject struct{…}`

            - `Message string`

            - `Type APIError`

              - `const APIErrorAPIError APIError = "api_error"`

          - `type OverloadedError struct{…}`

            - `Message string`

            - `Type OverloadedError`

              - `const OverloadedErrorOverloadedError OverloadedError = "overloaded_error"`

        - `RequestID string`

        - `Type Error`

          - `const ErrorError Error = "error"`

      - `Type Errored`

        - `const ErroredErrored Errored = "errored"`

    - `type MessageBatchCanceledResult struct{…}`

      - `Type Canceled`

        - `const CanceledCanceled Canceled = "canceled"`

    - `type MessageBatchExpiredResult struct{…}`

      - `Type Expired`

        - `const ExpiredExpired Expired = "expired"`

### Message Batch Request Counts

- `type MessageBatchRequestCounts struct{…}`

  - `Canceled int64`

    Number of requests in the Message Batch that have been canceled.

    This is zero until processing of the entire Message Batch has ended.

  - `Errored int64`

    Number of requests in the Message Batch that encountered an error.

    This is zero until processing of the entire Message Batch has ended.

  - `Expired int64`

    Number of requests in the Message Batch that have expired.

    This is zero until processing of the entire Message Batch has ended.

  - `Processing int64`

    Number of requests in the Message Batch that are processing.

  - `Succeeded int64`

    Number of requests in the Message Batch that have completed successfully.

    This is zero until processing of the entire Message Batch has ended.

### Message Batch Result

- `type MessageBatchResultUnion interface{…}`

  Processing result for this request.

  Contains a Message output if processing was successful, an error response if processing failed, or the reason why processing was not attempted, such as cancellation or expiration.

  - `type MessageBatchSucceededResult struct{…}`

    - `Message Message`

      - `ID string`

        Unique object identifier.

        The format and length of IDs may change over time.

      - `Container Container`

        Information about the container used in the request (for the code execution tool)

        - `ID string`

          Identifier for the container used in this request

        - `ExpiresAt Time`

          The time at which the container will expire.

      - `Content []ContentBlockUnion`

        Content generated by the model.

        This is an array of content blocks, each of which has a `type` that determines its shape.

        Example:

        ```json
        [{"type": "text", "text": "Hi, I'm Claude."}]
        ```

        If the request input `messages` ended with an `assistant` turn, then the response `content` will continue directly from that last turn. You can use this to constrain the model's output.

        For example, if the input `messages` were:

        ```json
        [
          {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
          {"role": "assistant", "content": "The best answer is ("}
        ]
        ```

        Then the response `content` might be:

        ```json
        [{"type": "text", "text": "B)"}]
        ```

        - `type TextBlock struct{…}`

          - `Citations []TextCitationUnion`

            Citations supporting the text block.

            The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

            - `type CitationCharLocation struct{…}`

              - `CitedText string`

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndCharIndex int64`

              - `FileID string`

              - `StartCharIndex int64`

              - `Type CharLocation`

                - `const CharLocationCharLocation CharLocation = "char_location"`

            - `type CitationPageLocation struct{…}`

              - `CitedText string`

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndPageNumber int64`

              - `FileID string`

              - `StartPageNumber int64`

              - `Type PageLocation`

                - `const PageLocationPageLocation PageLocation = "page_location"`

            - `type CitationContentBlockLocation struct{…}`

              - `CitedText string`

                The full text of the cited block range, concatenated.

                Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

              - `DocumentIndex int64`

              - `DocumentTitle string`

              - `EndBlockIndex int64`

                Exclusive 0-based end index of the cited block range in the source's `content` array.

                Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

              - `FileID string`

              - `StartBlockIndex int64`

                0-based index of the first cited block in the source's `content` array.

              - `Type ContentBlockLocation`

                - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

            - `type CitationsWebSearchResultLocation struct{…}`

              - `CitedText string`

              - `EncryptedIndex string`

              - `Title string`

              - `Type WebSearchResultLocation`

                - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

              - `URL string`

            - `type CitationsSearchResultLocation struct{…}`

              - `CitedText string`

                The full text of the cited block range, concatenated.

                Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

              - `EndBlockIndex int64`

                Exclusive 0-based end index of the cited block range in the source's `content` array.

                Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

              - `SearchResultIndex int64`

                0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

                Counted separately from `document_index`; server-side web search results are not included in this count.

              - `Source string`

              - `StartBlockIndex int64`

                0-based index of the first cited block in the source's `content` array.

              - `Title string`

              - `Type SearchResultLocation`

                - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

          - `Text string`

          - `Type Text`

            - `const TextText Text = "text"`

        - `type ThinkingBlock struct{…}`

          - `Signature string`

          - `Thinking string`

          - `Type Thinking`

            - `const ThinkingThinking Thinking = "thinking"`

        - `type RedactedThinkingBlock struct{…}`

          - `Data string`

          - `Type RedactedThinking`

            - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

        - `type ToolUseBlock struct{…}`

          - `ID string`

          - `Caller ToolUseBlockCallerUnion`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

              - `Type Direct`

                - `const DirectDirect Direct = "direct"`

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

              - `ToolID string`

              - `Type CodeExecution20250825`

                - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

            - `type ServerToolCaller20260120 struct{…}`

              - `ToolID string`

              - `Type CodeExecution20260120`

                - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

          - `Input map[string, any]`

          - `Name string`

          - `Type ToolUse`

            - `const ToolUseToolUse ToolUse = "tool_use"`

        - `type ServerToolUseBlock struct{…}`

          - `ID string`

          - `Caller ServerToolUseBlockCallerUnion`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

          - `Input map[string, any]`

          - `Name ServerToolUseBlockName`

            - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

            - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

            - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

            - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

            - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

            - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

            - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

          - `Type ServerToolUse`

            - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

        - `type WebSearchToolResultBlock struct{…}`

          - `Caller WebSearchToolResultBlockCallerUnion`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

          - `Content WebSearchToolResultBlockContentUnion`

            - `type WebSearchToolResultError struct{…}`

              - `ErrorCode WebSearchToolResultErrorCode`

                - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

                - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

                - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

                - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

                - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

                - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

              - `Type WebSearchToolResultError`

                - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

            - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

              - `EncryptedContent string`

              - `PageAge string`

              - `Title string`

              - `Type WebSearchResult`

                - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

              - `URL string`

          - `ToolUseID string`

          - `Type WebSearchToolResult`

            - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

        - `type WebFetchToolResultBlock struct{…}`

          - `Caller WebFetchToolResultBlockCallerUnion`

            Tool invocation directly from the model.

            - `type DirectCaller struct{…}`

              Tool invocation directly from the model.

            - `type ServerToolCaller struct{…}`

              Tool invocation generated by a server-side tool.

            - `type ServerToolCaller20260120 struct{…}`

          - `Content WebFetchToolResultBlockContentUnion`

            - `type WebFetchToolResultErrorBlock struct{…}`

              - `ErrorCode WebFetchToolResultErrorCode`

                - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

                - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

                - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

                - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

                - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

                - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

                - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

                - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

                - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

              - `Type WebFetchToolResultError`

                - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

            - `type WebFetchBlock struct{…}`

              - `Content DocumentBlock`

                - `Citations CitationsConfig`

                  Citation configuration for the document

                  - `Enabled bool`

                - `Source DocumentBlockSourceUnion`

                  - `type Base64PDFSource struct{…}`

                    - `Data string`

                    - `MediaType ApplicationPDF`

                      - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                    - `Type Base64`

                      - `const Base64Base64 Base64 = "base64"`

                  - `type PlainTextSource struct{…}`

                    - `Data string`

                    - `MediaType TextPlain`

                      - `const TextPlainTextPlain TextPlain = "text/plain"`

                    - `Type Text`

                      - `const TextText Text = "text"`

                - `Title string`

                  The title of the document

                - `Type Document`

                  - `const DocumentDocument Document = "document"`

              - `RetrievedAt string`

                ISO 8601 timestamp when the content was retrieved

              - `Type WebFetchResult`

                - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

              - `URL string`

                Fetched content URL

          - `ToolUseID string`

          - `Type WebFetchToolResult`

            - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

        - `type CodeExecutionToolResultBlock struct{…}`

          - `Content CodeExecutionToolResultBlockContentUnion`

            Code execution result with encrypted stdout for PFC + web_search results.

            - `type CodeExecutionToolResultError struct{…}`

              - `ErrorCode CodeExecutionToolResultErrorCode`

                - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

                - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `Type CodeExecutionToolResultError`

                - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

            - `type CodeExecutionResultBlock struct{…}`

              - `Content []CodeExecutionOutputBlock`

                - `FileID string`

                - `Type CodeExecutionOutput`

                  - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

              - `ReturnCode int64`

              - `Stderr string`

              - `Stdout string`

              - `Type CodeExecutionResult`

                - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

            - `type EncryptedCodeExecutionResultBlock struct{…}`

              Code execution result with encrypted stdout for PFC + web_search results.

              - `Content []CodeExecutionOutputBlock`

                - `FileID string`

                - `Type CodeExecutionOutput`

              - `EncryptedStdout string`

              - `ReturnCode int64`

              - `Stderr string`

              - `Type EncryptedCodeExecutionResult`

                - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

          - `ToolUseID string`

          - `Type CodeExecutionToolResult`

            - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

        - `type BashCodeExecutionToolResultBlock struct{…}`

          - `Content BashCodeExecutionToolResultBlockContentUnion`

            - `type BashCodeExecutionToolResultError struct{…}`

              - `ErrorCode BashCodeExecutionToolResultErrorCode`

                - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

                - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

              - `Type BashCodeExecutionToolResultError`

                - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

            - `type BashCodeExecutionResultBlock struct{…}`

              - `Content []BashCodeExecutionOutputBlock`

                - `FileID string`

                - `Type BashCodeExecutionOutput`

                  - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

              - `ReturnCode int64`

              - `Stderr string`

              - `Stdout string`

              - `Type BashCodeExecutionResult`

                - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

          - `ToolUseID string`

          - `Type BashCodeExecutionToolResult`

            - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

        - `type TextEditorCodeExecutionToolResultBlock struct{…}`

          - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

            - `type TextEditorCodeExecutionToolResultError struct{…}`

              - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

                - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

                - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

                - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

                - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

                - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

              - `ErrorMessage string`

              - `Type TextEditorCodeExecutionToolResultError`

                - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

            - `type TextEditorCodeExecutionViewResultBlock struct{…}`

              - `Content string`

              - `FileType TextEditorCodeExecutionViewResultBlockFileType`

                - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

                - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

                - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

              - `NumLines int64`

              - `StartLine int64`

              - `TotalLines int64`

              - `Type TextEditorCodeExecutionViewResult`

                - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

            - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

              - `IsFileUpdate bool`

              - `Type TextEditorCodeExecutionCreateResult`

                - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

            - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

              - `Lines []string`

              - `NewLines int64`

              - `NewStart int64`

              - `OldLines int64`

              - `OldStart int64`

              - `Type TextEditorCodeExecutionStrReplaceResult`

                - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

          - `ToolUseID string`

          - `Type TextEditorCodeExecutionToolResult`

            - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

        - `type ToolSearchToolResultBlock struct{…}`

          - `Content ToolSearchToolResultBlockContentUnion`

            - `type ToolSearchToolResultError struct{…}`

              - `ErrorCode ToolSearchToolResultErrorCode`

                - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

                - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

                - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

                - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

              - `ErrorMessage string`

              - `Type ToolSearchToolResultError`

                - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

            - `type ToolSearchToolSearchResultBlock struct{…}`

              - `ToolReferences []ToolReferenceBlock`

                - `ToolName string`

                - `Type ToolReference`

                  - `const ToolReferenceToolReference ToolReference = "tool_reference"`

              - `Type ToolSearchToolSearchResult`

                - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

          - `ToolUseID string`

          - `Type ToolSearchToolResult`

            - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

        - `type ContainerUploadBlock struct{…}`

          Response model for a file uploaded to the container.

          - `FileID string`

          - `Type ContainerUpload`

            - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

      - `Model Model`

        The model that will complete your prompt.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `type Model string`

          The model that will complete your prompt.

          See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

          - `const ModelClaudeFable5 Model = "claude-fable-5"`

            Next generation of intelligence for the hardest knowledge work and coding problems

          - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

            Most capable model for cybersecurity and biology research

          - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

            Frontier intelligence for long-running agents and coding

          - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

            Frontier intelligence for long-running agents and coding

          - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

            New class of intelligence, strongest in coding and cybersecurity

          - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

            Frontier intelligence for long-running agents and coding

          - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

            Best combination of speed and intelligence

          - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

            Fastest model with near-frontier intelligence

          - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

            Fastest model with near-frontier intelligence

          - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

            Premium model combining maximum intelligence with practical performance

          - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

            Premium model combining maximum intelligence with practical performance

          - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

            High-performance model for agents and coding

          - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

            High-performance model for agents and coding

          - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

            Exceptional model for specialized complex tasks

          - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

            Exceptional model for specialized complex tasks

          - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

            Powerful model for complex tasks

          - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

            Powerful model for complex tasks

          - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

            High-performance model with extended thinking

          - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

            High-performance model with extended thinking

          - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

            Fast and cost-effective model

        - `string`

      - `Role Assistant`

        Conversational role of the generated message.

        This will always be `"assistant"`.

        - `const AssistantAssistant Assistant = "assistant"`

      - `StopDetails RefusalStopDetails`

        Structured information about a refusal.

        - `Category RefusalStopDetailsCategory`

          The policy category that triggered the refusal.

          `null` when the refusal doesn't map to a named category.

          - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

          - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

          - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

        - `Explanation string`

          Human-readable explanation of the refusal.

          This text is not guaranteed to be stable. `null` when no explanation is available for the category.

        - `Type Refusal`

          - `const RefusalRefusal Refusal = "refusal"`

      - `StopReason StopReason`

        The reason that we stopped.

        This may be one the following values:

        * `"end_turn"`: the model reached a natural stopping point
        * `"max_tokens"`: we exceeded the requested `max_tokens` or the model's maximum
        * `"stop_sequence"`: one of your provided custom `stop_sequences` was generated
        * `"tool_use"`: the model invoked one or more tools
        * `"pause_turn"`: we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
        * `"refusal"`: when streaming classifiers intervene to handle potential policy violations

        In non-streaming mode this value is always non-null. In streaming mode, it is null in the `message_start` event and non-null otherwise.

        - `const StopReasonEndTurn StopReason = "end_turn"`

        - `const StopReasonMaxTokens StopReason = "max_tokens"`

        - `const StopReasonStopSequence StopReason = "stop_sequence"`

        - `const StopReasonToolUse StopReason = "tool_use"`

        - `const StopReasonPauseTurn StopReason = "pause_turn"`

        - `const StopReasonRefusal StopReason = "refusal"`

      - `StopSequence string`

        Which custom stop sequence was generated, if any.

        This value will be a non-null string if one of your custom stop sequences was generated.

      - `Type Message`

        Object type.

        For Messages, this is always `"message"`.

        - `const MessageMessage Message = "message"`

      - `Usage Usage`

        Billing and rate-limit usage.

        Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

        Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

        For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

        Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

        - `CacheCreation CacheCreation`

          Breakdown of cached tokens by TTL

          - `Ephemeral1hInputTokens int64`

            The number of input tokens used to create the 1 hour cache entry.

          - `Ephemeral5mInputTokens int64`

            The number of input tokens used to create the 5 minute cache entry.

        - `CacheCreationInputTokens int64`

          The number of input tokens used to create the cache entry.

        - `CacheReadInputTokens int64`

          The number of input tokens read from the cache.

        - `InferenceGeo string`

          The geographic region where inference was performed for this request.

        - `InputTokens int64`

          The number of input tokens which were used.

        - `OutputTokens int64`

          The number of output tokens which were used.

        - `OutputTokensDetails OutputTokensDetails`

          Breakdown of output tokens by category.

          `output_tokens` remains the inclusive, authoritative total used for billing.
          This object provides a read-only decomposition for observability — for example,
          how many of the billed output tokens were spent on internal reasoning that may
          have been summarized before being returned to you.

          - `ThinkingTokens int64`

            Number of output tokens the model generated as internal reasoning, including
            the thinking-block delimiter tokens.

            Reflects the raw reasoning the model produced, not the (possibly shorter)
            summarized thinking text returned in the response body. Computed by
            re-tokenizing the raw reasoning text, so it may differ from the model's exact
            generation count by a small number of tokens. Always ≤ `output_tokens`;
            `output_tokens - thinking_tokens` approximates the non-reasoning output.

        - `ServerToolUse ServerToolUsage`

          The number of server tool requests.

          - `WebFetchRequests int64`

            The number of web fetch tool requests.

          - `WebSearchRequests int64`

            The number of web search tool requests.

        - `ServiceTier UsageServiceTier`

          If the request used the priority, standard, or batch tier.

          - `const UsageServiceTierStandard UsageServiceTier = "standard"`

          - `const UsageServiceTierPriority UsageServiceTier = "priority"`

          - `const UsageServiceTierBatch UsageServiceTier = "batch"`

    - `Type Succeeded`

      - `const SucceededSucceeded Succeeded = "succeeded"`

  - `type MessageBatchErroredResult struct{…}`

    - `Error ErrorResponse`

      - `Error ErrorObjectUnion`

        - `type InvalidRequestError struct{…}`

          - `Message string`

          - `Type InvalidRequestError`

            - `const InvalidRequestErrorInvalidRequestError InvalidRequestError = "invalid_request_error"`

        - `type AuthenticationError struct{…}`

          - `Message string`

          - `Type AuthenticationError`

            - `const AuthenticationErrorAuthenticationError AuthenticationError = "authentication_error"`

        - `type BillingError struct{…}`

          - `Message string`

          - `Type BillingError`

            - `const BillingErrorBillingError BillingError = "billing_error"`

        - `type PermissionError struct{…}`

          - `Message string`

          - `Type PermissionError`

            - `const PermissionErrorPermissionError PermissionError = "permission_error"`

        - `type NotFoundError struct{…}`

          - `Message string`

          - `Type NotFoundError`

            - `const NotFoundErrorNotFoundError NotFoundError = "not_found_error"`

        - `type RateLimitError struct{…}`

          - `Message string`

          - `Type RateLimitError`

            - `const RateLimitErrorRateLimitError RateLimitError = "rate_limit_error"`

        - `type GatewayTimeoutError struct{…}`

          - `Message string`

          - `Type TimeoutError`

            - `const TimeoutErrorTimeoutError TimeoutError = "timeout_error"`

        - `type APIErrorObject struct{…}`

          - `Message string`

          - `Type APIError`

            - `const APIErrorAPIError APIError = "api_error"`

        - `type OverloadedError struct{…}`

          - `Message string`

          - `Type OverloadedError`

            - `const OverloadedErrorOverloadedError OverloadedError = "overloaded_error"`

      - `RequestID string`

      - `Type Error`

        - `const ErrorError Error = "error"`

    - `Type Errored`

      - `const ErroredErrored Errored = "errored"`

  - `type MessageBatchCanceledResult struct{…}`

    - `Type Canceled`

      - `const CanceledCanceled Canceled = "canceled"`

  - `type MessageBatchExpiredResult struct{…}`

    - `Type Expired`

      - `const ExpiredExpired Expired = "expired"`

### Message Batch Succeeded Result

- `type MessageBatchSucceededResult struct{…}`

  - `Message Message`

    - `ID string`

      Unique object identifier.

      The format and length of IDs may change over time.

    - `Container Container`

      Information about the container used in the request (for the code execution tool)

      - `ID string`

        Identifier for the container used in this request

      - `ExpiresAt Time`

        The time at which the container will expire.

    - `Content []ContentBlockUnion`

      Content generated by the model.

      This is an array of content blocks, each of which has a `type` that determines its shape.

      Example:

      ```json
      [{"type": "text", "text": "Hi, I'm Claude."}]
      ```

      If the request input `messages` ended with an `assistant` turn, then the response `content` will continue directly from that last turn. You can use this to constrain the model's output.

      For example, if the input `messages` were:

      ```json
      [
        {"role": "user", "content": "What's the Greek name for Sun? (A) Sol (B) Helios (C) Sun"},
        {"role": "assistant", "content": "The best answer is ("}
      ]
      ```

      Then the response `content` might be:

      ```json
      [{"type": "text", "text": "B)"}]
      ```

      - `type TextBlock struct{…}`

        - `Citations []TextCitationUnion`

          Citations supporting the text block.

          The type of citation returned will depend on the type of document being cited. Citing a PDF results in `page_location`, plain text results in `char_location`, and content document results in `content_block_location`.

          - `type CitationCharLocation struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndCharIndex int64`

            - `FileID string`

            - `StartCharIndex int64`

            - `Type CharLocation`

              - `const CharLocationCharLocation CharLocation = "char_location"`

          - `type CitationPageLocation struct{…}`

            - `CitedText string`

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndPageNumber int64`

            - `FileID string`

            - `StartPageNumber int64`

            - `Type PageLocation`

              - `const PageLocationPageLocation PageLocation = "page_location"`

          - `type CitationContentBlockLocation struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `DocumentIndex int64`

            - `DocumentTitle string`

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `FileID string`

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Type ContentBlockLocation`

              - `const ContentBlockLocationContentBlockLocation ContentBlockLocation = "content_block_location"`

          - `type CitationsWebSearchResultLocation struct{…}`

            - `CitedText string`

            - `EncryptedIndex string`

            - `Title string`

            - `Type WebSearchResultLocation`

              - `const WebSearchResultLocationWebSearchResultLocation WebSearchResultLocation = "web_search_result_location"`

            - `URL string`

          - `type CitationsSearchResultLocation struct{…}`

            - `CitedText string`

              The full text of the cited block range, concatenated.

              Always equals the contents of `content[start_block_index:end_block_index]` joined together. The text block is the minimal citable unit; this field is never a substring of a single block. Not counted toward output tokens, and not counted toward input tokens when sent back in subsequent turns.

            - `EndBlockIndex int64`

              Exclusive 0-based end index of the cited block range in the source's `content` array.

              Always greater than `start_block_index`; a single-block citation has `end_block_index = start_block_index + 1`.

            - `SearchResultIndex int64`

              0-based index of the cited search result among all `search_result` content blocks in the request, in the order they appear across messages and tool results.

              Counted separately from `document_index`; server-side web search results are not included in this count.

            - `Source string`

            - `StartBlockIndex int64`

              0-based index of the first cited block in the source's `content` array.

            - `Title string`

            - `Type SearchResultLocation`

              - `const SearchResultLocationSearchResultLocation SearchResultLocation = "search_result_location"`

        - `Text string`

        - `Type Text`

          - `const TextText Text = "text"`

      - `type ThinkingBlock struct{…}`

        - `Signature string`

        - `Thinking string`

        - `Type Thinking`

          - `const ThinkingThinking Thinking = "thinking"`

      - `type RedactedThinkingBlock struct{…}`

        - `Data string`

        - `Type RedactedThinking`

          - `const RedactedThinkingRedactedThinking RedactedThinking = "redacted_thinking"`

      - `type ToolUseBlock struct{…}`

        - `ID string`

        - `Caller ToolUseBlockCallerUnion`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

            - `Type Direct`

              - `const DirectDirect Direct = "direct"`

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

            - `ToolID string`

            - `Type CodeExecution20250825`

              - `const CodeExecution20250825CodeExecution20250825 CodeExecution20250825 = "code_execution_20250825"`

          - `type ServerToolCaller20260120 struct{…}`

            - `ToolID string`

            - `Type CodeExecution20260120`

              - `const CodeExecution20260120CodeExecution20260120 CodeExecution20260120 = "code_execution_20260120"`

        - `Input map[string, any]`

        - `Name string`

        - `Type ToolUse`

          - `const ToolUseToolUse ToolUse = "tool_use"`

      - `type ServerToolUseBlock struct{…}`

        - `ID string`

        - `Caller ServerToolUseBlockCallerUnion`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

          - `type ServerToolCaller20260120 struct{…}`

        - `Input map[string, any]`

        - `Name ServerToolUseBlockName`

          - `const ServerToolUseBlockNameWebSearch ServerToolUseBlockName = "web_search"`

          - `const ServerToolUseBlockNameWebFetch ServerToolUseBlockName = "web_fetch"`

          - `const ServerToolUseBlockNameCodeExecution ServerToolUseBlockName = "code_execution"`

          - `const ServerToolUseBlockNameBashCodeExecution ServerToolUseBlockName = "bash_code_execution"`

          - `const ServerToolUseBlockNameTextEditorCodeExecution ServerToolUseBlockName = "text_editor_code_execution"`

          - `const ServerToolUseBlockNameToolSearchToolRegex ServerToolUseBlockName = "tool_search_tool_regex"`

          - `const ServerToolUseBlockNameToolSearchToolBm25 ServerToolUseBlockName = "tool_search_tool_bm25"`

        - `Type ServerToolUse`

          - `const ServerToolUseServerToolUse ServerToolUse = "server_tool_use"`

      - `type WebSearchToolResultBlock struct{…}`

        - `Caller WebSearchToolResultBlockCallerUnion`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

          - `type ServerToolCaller20260120 struct{…}`

        - `Content WebSearchToolResultBlockContentUnion`

          - `type WebSearchToolResultError struct{…}`

            - `ErrorCode WebSearchToolResultErrorCode`

              - `const WebSearchToolResultErrorCodeInvalidToolInput WebSearchToolResultErrorCode = "invalid_tool_input"`

              - `const WebSearchToolResultErrorCodeUnavailable WebSearchToolResultErrorCode = "unavailable"`

              - `const WebSearchToolResultErrorCodeMaxUsesExceeded WebSearchToolResultErrorCode = "max_uses_exceeded"`

              - `const WebSearchToolResultErrorCodeTooManyRequests WebSearchToolResultErrorCode = "too_many_requests"`

              - `const WebSearchToolResultErrorCodeQueryTooLong WebSearchToolResultErrorCode = "query_too_long"`

              - `const WebSearchToolResultErrorCodeRequestTooLarge WebSearchToolResultErrorCode = "request_too_large"`

            - `Type WebSearchToolResultError`

              - `const WebSearchToolResultErrorWebSearchToolResultError WebSearchToolResultError = "web_search_tool_result_error"`

          - `type WebSearchToolResultBlockContentArray []WebSearchResultBlock`

            - `EncryptedContent string`

            - `PageAge string`

            - `Title string`

            - `Type WebSearchResult`

              - `const WebSearchResultWebSearchResult WebSearchResult = "web_search_result"`

            - `URL string`

        - `ToolUseID string`

        - `Type WebSearchToolResult`

          - `const WebSearchToolResultWebSearchToolResult WebSearchToolResult = "web_search_tool_result"`

      - `type WebFetchToolResultBlock struct{…}`

        - `Caller WebFetchToolResultBlockCallerUnion`

          Tool invocation directly from the model.

          - `type DirectCaller struct{…}`

            Tool invocation directly from the model.

          - `type ServerToolCaller struct{…}`

            Tool invocation generated by a server-side tool.

          - `type ServerToolCaller20260120 struct{…}`

        - `Content WebFetchToolResultBlockContentUnion`

          - `type WebFetchToolResultErrorBlock struct{…}`

            - `ErrorCode WebFetchToolResultErrorCode`

              - `const WebFetchToolResultErrorCodeInvalidToolInput WebFetchToolResultErrorCode = "invalid_tool_input"`

              - `const WebFetchToolResultErrorCodeURLTooLong WebFetchToolResultErrorCode = "url_too_long"`

              - `const WebFetchToolResultErrorCodeURLNotAllowed WebFetchToolResultErrorCode = "url_not_allowed"`

              - `const WebFetchToolResultErrorCodeURLNotInPriorContext WebFetchToolResultErrorCode = "url_not_in_prior_context"`

              - `const WebFetchToolResultErrorCodeURLNotAccessible WebFetchToolResultErrorCode = "url_not_accessible"`

              - `const WebFetchToolResultErrorCodeUnsupportedContentType WebFetchToolResultErrorCode = "unsupported_content_type"`

              - `const WebFetchToolResultErrorCodeTooManyRequests WebFetchToolResultErrorCode = "too_many_requests"`

              - `const WebFetchToolResultErrorCodeMaxUsesExceeded WebFetchToolResultErrorCode = "max_uses_exceeded"`

              - `const WebFetchToolResultErrorCodeUnavailable WebFetchToolResultErrorCode = "unavailable"`

            - `Type WebFetchToolResultError`

              - `const WebFetchToolResultErrorWebFetchToolResultError WebFetchToolResultError = "web_fetch_tool_result_error"`

          - `type WebFetchBlock struct{…}`

            - `Content DocumentBlock`

              - `Citations CitationsConfig`

                Citation configuration for the document

                - `Enabled bool`

              - `Source DocumentBlockSourceUnion`

                - `type Base64PDFSource struct{…}`

                  - `Data string`

                  - `MediaType ApplicationPDF`

                    - `const ApplicationPDFApplicationPDF ApplicationPDF = "application/pdf"`

                  - `Type Base64`

                    - `const Base64Base64 Base64 = "base64"`

                - `type PlainTextSource struct{…}`

                  - `Data string`

                  - `MediaType TextPlain`

                    - `const TextPlainTextPlain TextPlain = "text/plain"`

                  - `Type Text`

                    - `const TextText Text = "text"`

              - `Title string`

                The title of the document

              - `Type Document`

                - `const DocumentDocument Document = "document"`

            - `RetrievedAt string`

              ISO 8601 timestamp when the content was retrieved

            - `Type WebFetchResult`

              - `const WebFetchResultWebFetchResult WebFetchResult = "web_fetch_result"`

            - `URL string`

              Fetched content URL

        - `ToolUseID string`

        - `Type WebFetchToolResult`

          - `const WebFetchToolResultWebFetchToolResult WebFetchToolResult = "web_fetch_tool_result"`

      - `type CodeExecutionToolResultBlock struct{…}`

        - `Content CodeExecutionToolResultBlockContentUnion`

          Code execution result with encrypted stdout for PFC + web_search results.

          - `type CodeExecutionToolResultError struct{…}`

            - `ErrorCode CodeExecutionToolResultErrorCode`

              - `const CodeExecutionToolResultErrorCodeInvalidToolInput CodeExecutionToolResultErrorCode = "invalid_tool_input"`

              - `const CodeExecutionToolResultErrorCodeUnavailable CodeExecutionToolResultErrorCode = "unavailable"`

              - `const CodeExecutionToolResultErrorCodeTooManyRequests CodeExecutionToolResultErrorCode = "too_many_requests"`

              - `const CodeExecutionToolResultErrorCodeExecutionTimeExceeded CodeExecutionToolResultErrorCode = "execution_time_exceeded"`

            - `Type CodeExecutionToolResultError`

              - `const CodeExecutionToolResultErrorCodeExecutionToolResultError CodeExecutionToolResultError = "code_execution_tool_result_error"`

          - `type CodeExecutionResultBlock struct{…}`

            - `Content []CodeExecutionOutputBlock`

              - `FileID string`

              - `Type CodeExecutionOutput`

                - `const CodeExecutionOutputCodeExecutionOutput CodeExecutionOutput = "code_execution_output"`

            - `ReturnCode int64`

            - `Stderr string`

            - `Stdout string`

            - `Type CodeExecutionResult`

              - `const CodeExecutionResultCodeExecutionResult CodeExecutionResult = "code_execution_result"`

          - `type EncryptedCodeExecutionResultBlock struct{…}`

            Code execution result with encrypted stdout for PFC + web_search results.

            - `Content []CodeExecutionOutputBlock`

              - `FileID string`

              - `Type CodeExecutionOutput`

            - `EncryptedStdout string`

            - `ReturnCode int64`

            - `Stderr string`

            - `Type EncryptedCodeExecutionResult`

              - `const EncryptedCodeExecutionResultEncryptedCodeExecutionResult EncryptedCodeExecutionResult = "encrypted_code_execution_result"`

        - `ToolUseID string`

        - `Type CodeExecutionToolResult`

          - `const CodeExecutionToolResultCodeExecutionToolResult CodeExecutionToolResult = "code_execution_tool_result"`

      - `type BashCodeExecutionToolResultBlock struct{…}`

        - `Content BashCodeExecutionToolResultBlockContentUnion`

          - `type BashCodeExecutionToolResultError struct{…}`

            - `ErrorCode BashCodeExecutionToolResultErrorCode`

              - `const BashCodeExecutionToolResultErrorCodeInvalidToolInput BashCodeExecutionToolResultErrorCode = "invalid_tool_input"`

              - `const BashCodeExecutionToolResultErrorCodeUnavailable BashCodeExecutionToolResultErrorCode = "unavailable"`

              - `const BashCodeExecutionToolResultErrorCodeTooManyRequests BashCodeExecutionToolResultErrorCode = "too_many_requests"`

              - `const BashCodeExecutionToolResultErrorCodeExecutionTimeExceeded BashCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `const BashCodeExecutionToolResultErrorCodeOutputFileTooLarge BashCodeExecutionToolResultErrorCode = "output_file_too_large"`

            - `Type BashCodeExecutionToolResultError`

              - `const BashCodeExecutionToolResultErrorBashCodeExecutionToolResultError BashCodeExecutionToolResultError = "bash_code_execution_tool_result_error"`

          - `type BashCodeExecutionResultBlock struct{…}`

            - `Content []BashCodeExecutionOutputBlock`

              - `FileID string`

              - `Type BashCodeExecutionOutput`

                - `const BashCodeExecutionOutputBashCodeExecutionOutput BashCodeExecutionOutput = "bash_code_execution_output"`

            - `ReturnCode int64`

            - `Stderr string`

            - `Stdout string`

            - `Type BashCodeExecutionResult`

              - `const BashCodeExecutionResultBashCodeExecutionResult BashCodeExecutionResult = "bash_code_execution_result"`

        - `ToolUseID string`

        - `Type BashCodeExecutionToolResult`

          - `const BashCodeExecutionToolResultBashCodeExecutionToolResult BashCodeExecutionToolResult = "bash_code_execution_tool_result"`

      - `type TextEditorCodeExecutionToolResultBlock struct{…}`

        - `Content TextEditorCodeExecutionToolResultBlockContentUnion`

          - `type TextEditorCodeExecutionToolResultError struct{…}`

            - `ErrorCode TextEditorCodeExecutionToolResultErrorCode`

              - `const TextEditorCodeExecutionToolResultErrorCodeInvalidToolInput TextEditorCodeExecutionToolResultErrorCode = "invalid_tool_input"`

              - `const TextEditorCodeExecutionToolResultErrorCodeUnavailable TextEditorCodeExecutionToolResultErrorCode = "unavailable"`

              - `const TextEditorCodeExecutionToolResultErrorCodeTooManyRequests TextEditorCodeExecutionToolResultErrorCode = "too_many_requests"`

              - `const TextEditorCodeExecutionToolResultErrorCodeExecutionTimeExceeded TextEditorCodeExecutionToolResultErrorCode = "execution_time_exceeded"`

              - `const TextEditorCodeExecutionToolResultErrorCodeFileNotFound TextEditorCodeExecutionToolResultErrorCode = "file_not_found"`

            - `ErrorMessage string`

            - `Type TextEditorCodeExecutionToolResultError`

              - `const TextEditorCodeExecutionToolResultErrorTextEditorCodeExecutionToolResultError TextEditorCodeExecutionToolResultError = "text_editor_code_execution_tool_result_error"`

          - `type TextEditorCodeExecutionViewResultBlock struct{…}`

            - `Content string`

            - `FileType TextEditorCodeExecutionViewResultBlockFileType`

              - `const TextEditorCodeExecutionViewResultBlockFileTypeText TextEditorCodeExecutionViewResultBlockFileType = "text"`

              - `const TextEditorCodeExecutionViewResultBlockFileTypeImage TextEditorCodeExecutionViewResultBlockFileType = "image"`

              - `const TextEditorCodeExecutionViewResultBlockFileTypePDF TextEditorCodeExecutionViewResultBlockFileType = "pdf"`

            - `NumLines int64`

            - `StartLine int64`

            - `TotalLines int64`

            - `Type TextEditorCodeExecutionViewResult`

              - `const TextEditorCodeExecutionViewResultTextEditorCodeExecutionViewResult TextEditorCodeExecutionViewResult = "text_editor_code_execution_view_result"`

          - `type TextEditorCodeExecutionCreateResultBlock struct{…}`

            - `IsFileUpdate bool`

            - `Type TextEditorCodeExecutionCreateResult`

              - `const TextEditorCodeExecutionCreateResultTextEditorCodeExecutionCreateResult TextEditorCodeExecutionCreateResult = "text_editor_code_execution_create_result"`

          - `type TextEditorCodeExecutionStrReplaceResultBlock struct{…}`

            - `Lines []string`

            - `NewLines int64`

            - `NewStart int64`

            - `OldLines int64`

            - `OldStart int64`

            - `Type TextEditorCodeExecutionStrReplaceResult`

              - `const TextEditorCodeExecutionStrReplaceResultTextEditorCodeExecutionStrReplaceResult TextEditorCodeExecutionStrReplaceResult = "text_editor_code_execution_str_replace_result"`

        - `ToolUseID string`

        - `Type TextEditorCodeExecutionToolResult`

          - `const TextEditorCodeExecutionToolResultTextEditorCodeExecutionToolResult TextEditorCodeExecutionToolResult = "text_editor_code_execution_tool_result"`

      - `type ToolSearchToolResultBlock struct{…}`

        - `Content ToolSearchToolResultBlockContentUnion`

          - `type ToolSearchToolResultError struct{…}`

            - `ErrorCode ToolSearchToolResultErrorCode`

              - `const ToolSearchToolResultErrorCodeInvalidToolInput ToolSearchToolResultErrorCode = "invalid_tool_input"`

              - `const ToolSearchToolResultErrorCodeUnavailable ToolSearchToolResultErrorCode = "unavailable"`

              - `const ToolSearchToolResultErrorCodeTooManyRequests ToolSearchToolResultErrorCode = "too_many_requests"`

              - `const ToolSearchToolResultErrorCodeExecutionTimeExceeded ToolSearchToolResultErrorCode = "execution_time_exceeded"`

            - `ErrorMessage string`

            - `Type ToolSearchToolResultError`

              - `const ToolSearchToolResultErrorToolSearchToolResultError ToolSearchToolResultError = "tool_search_tool_result_error"`

          - `type ToolSearchToolSearchResultBlock struct{…}`

            - `ToolReferences []ToolReferenceBlock`

              - `ToolName string`

              - `Type ToolReference`

                - `const ToolReferenceToolReference ToolReference = "tool_reference"`

            - `Type ToolSearchToolSearchResult`

              - `const ToolSearchToolSearchResultToolSearchToolSearchResult ToolSearchToolSearchResult = "tool_search_tool_search_result"`

        - `ToolUseID string`

        - `Type ToolSearchToolResult`

          - `const ToolSearchToolResultToolSearchToolResult ToolSearchToolResult = "tool_search_tool_result"`

      - `type ContainerUploadBlock struct{…}`

        Response model for a file uploaded to the container.

        - `FileID string`

        - `Type ContainerUpload`

          - `const ContainerUploadContainerUpload ContainerUpload = "container_upload"`

    - `Model Model`

      The model that will complete your prompt.

      See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

      - `type Model string`

        The model that will complete your prompt.

        See [models](https://docs.anthropic.com/en/docs/models-overview) for additional details and options.

        - `const ModelClaudeFable5 Model = "claude-fable-5"`

          Next generation of intelligence for the hardest knowledge work and coding problems

        - `const ModelClaudeMythos5 Model = "claude-mythos-5"`

          Most capable model for cybersecurity and biology research

        - `const ModelClaudeOpus4_8 Model = "claude-opus-4-8"`

          Frontier intelligence for long-running agents and coding

        - `const ModelClaudeOpus4_7 Model = "claude-opus-4-7"`

          Frontier intelligence for long-running agents and coding

        - `const ModelClaudeMythosPreview Model = "claude-mythos-preview"`

          New class of intelligence, strongest in coding and cybersecurity

        - `const ModelClaudeOpus4_6 Model = "claude-opus-4-6"`

          Frontier intelligence for long-running agents and coding

        - `const ModelClaudeSonnet4_6 Model = "claude-sonnet-4-6"`

          Best combination of speed and intelligence

        - `const ModelClaudeHaiku4_5 Model = "claude-haiku-4-5"`

          Fastest model with near-frontier intelligence

        - `const ModelClaudeHaiku4_5_20251001 Model = "claude-haiku-4-5-20251001"`

          Fastest model with near-frontier intelligence

        - `const ModelClaudeOpus4_5 Model = "claude-opus-4-5"`

          Premium model combining maximum intelligence with practical performance

        - `const ModelClaudeOpus4_5_20251101 Model = "claude-opus-4-5-20251101"`

          Premium model combining maximum intelligence with practical performance

        - `const ModelClaudeSonnet4_5 Model = "claude-sonnet-4-5"`

          High-performance model for agents and coding

        - `const ModelClaudeSonnet4_5_20250929 Model = "claude-sonnet-4-5-20250929"`

          High-performance model for agents and coding

        - `const ModelClaudeOpus4_1 Model = "claude-opus-4-1"`

          Exceptional model for specialized complex tasks

        - `const ModelClaudeOpus4_1_20250805 Model = "claude-opus-4-1-20250805"`

          Exceptional model for specialized complex tasks

        - `const ModelClaudeOpus4_0 Model = "claude-opus-4-0"`

          Powerful model for complex tasks

        - `const ModelClaudeOpus4_20250514 Model = "claude-opus-4-20250514"`

          Powerful model for complex tasks

        - `const ModelClaudeSonnet4_0 Model = "claude-sonnet-4-0"`

          High-performance model with extended thinking

        - `const ModelClaudeSonnet4_20250514 Model = "claude-sonnet-4-20250514"`

          High-performance model with extended thinking

        - `const ModelClaude_3_Haiku_20240307 Model = "claude-3-haiku-20240307"`

          Fast and cost-effective model

      - `string`

    - `Role Assistant`

      Conversational role of the generated message.

      This will always be `"assistant"`.

      - `const AssistantAssistant Assistant = "assistant"`

    - `StopDetails RefusalStopDetails`

      Structured information about a refusal.

      - `Category RefusalStopDetailsCategory`

        The policy category that triggered the refusal.

        `null` when the refusal doesn't map to a named category.

        - `const RefusalStopDetailsCategoryCyber RefusalStopDetailsCategory = "cyber"`

        - `const RefusalStopDetailsCategoryBio RefusalStopDetailsCategory = "bio"`

        - `const RefusalStopDetailsCategoryReasoningExtraction RefusalStopDetailsCategory = "reasoning_extraction"`

      - `Explanation string`

        Human-readable explanation of the refusal.

        This text is not guaranteed to be stable. `null` when no explanation is available for the category.

      - `Type Refusal`

        - `const RefusalRefusal Refusal = "refusal"`

    - `StopReason StopReason`

      The reason that we stopped.

      This may be one the following values:

      * `"end_turn"`: the model reached a natural stopping point
      * `"max_tokens"`: we exceeded the requested `max_tokens` or the model's maximum
      * `"stop_sequence"`: one of your provided custom `stop_sequences` was generated
      * `"tool_use"`: the model invoked one or more tools
      * `"pause_turn"`: we paused a long-running turn. You may provide the response back as-is in a subsequent request to let the model continue.
      * `"refusal"`: when streaming classifiers intervene to handle potential policy violations

      In non-streaming mode this value is always non-null. In streaming mode, it is null in the `message_start` event and non-null otherwise.

      - `const StopReasonEndTurn StopReason = "end_turn"`

      - `const StopReasonMaxTokens StopReason = "max_tokens"`

      - `const StopReasonStopSequence StopReason = "stop_sequence"`

      - `const StopReasonToolUse StopReason = "tool_use"`

      - `const StopReasonPauseTurn StopReason = "pause_turn"`

      - `const StopReasonRefusal StopReason = "refusal"`

    - `StopSequence string`

      Which custom stop sequence was generated, if any.

      This value will be a non-null string if one of your custom stop sequences was generated.

    - `Type Message`

      Object type.

      For Messages, this is always `"message"`.

      - `const MessageMessage Message = "message"`

    - `Usage Usage`

      Billing and rate-limit usage.

      Anthropic's API bills and rate-limits by token counts, as tokens represent the underlying cost to our systems.

      Under the hood, the API transforms requests into a format suitable for the model. The model's output then goes through a parsing stage before becoming an API response. As a result, the token counts in `usage` will not match one-to-one with the exact visible content of an API request or response.

      For example, `output_tokens` will be non-zero, even for an empty string response from Claude.

      Total input tokens in a request is the summation of `input_tokens`, `cache_creation_input_tokens`, and `cache_read_input_tokens`.

      - `CacheCreation CacheCreation`

        Breakdown of cached tokens by TTL

        - `Ephemeral1hInputTokens int64`

          The number of input tokens used to create the 1 hour cache entry.

        - `Ephemeral5mInputTokens int64`

          The number of input tokens used to create the 5 minute cache entry.

      - `CacheCreationInputTokens int64`

        The number of input tokens used to create the cache entry.

      - `CacheReadInputTokens int64`

        The number of input tokens read from the cache.

      - `InferenceGeo string`

        The geographic region where inference was performed for this request.

      - `InputTokens int64`

        The number of input tokens which were used.

      - `OutputTokens int64`

        The number of output tokens which were used.

      - `OutputTokensDetails OutputTokensDetails`

        Breakdown of output tokens by category.

        `output_tokens` remains the inclusive, authoritative total used for billing.
        This object provides a read-only decomposition for observability — for example,
        how many of the billed output tokens were spent on internal reasoning that may
        have been summarized before being returned to you.

        - `ThinkingTokens int64`

          Number of output tokens the model generated as internal reasoning, including
          the thinking-block delimiter tokens.

          Reflects the raw reasoning the model produced, not the (possibly shorter)
          summarized thinking text returned in the response body. Computed by
          re-tokenizing the raw reasoning text, so it may differ from the model's exact
          generation count by a small number of tokens. Always ≤ `output_tokens`;
          `output_tokens - thinking_tokens` approximates the non-reasoning output.

      - `ServerToolUse ServerToolUsage`

        The number of server tool requests.

        - `WebFetchRequests int64`

          The number of web fetch tool requests.

        - `WebSearchRequests int64`

          The number of web search tool requests.

      - `ServiceTier UsageServiceTier`

        If the request used the priority, standard, or batch tier.

        - `const UsageServiceTierStandard UsageServiceTier = "standard"`

        - `const UsageServiceTierPriority UsageServiceTier = "priority"`

        - `const UsageServiceTierBatch UsageServiceTier = "batch"`

  - `Type Succeeded`

    - `const SucceededSucceeded Succeeded = "succeeded"`
