# Events

## List Session Thread Events

`beta.sessions.threads.events.list(thread_id, **kwargs) -> PageCursor<BetaManagedAgentsSessionEvent>`

**get** `/v1/sessions/{session_id}/threads/{thread_id}/events`

List Session Thread Events

### Parameters

- `session_id: String`

- `thread_id: String`

- `limit: Integer`

  Query parameter for limit

- `page: String`

  Query parameter for page

- `betas: Array[AnthropicBeta]`

  Optional header to specify the beta version(s) you want to use.

  - `String = String`

  - `AnthropicBeta = :"message-batches-2024-09-24" | :"prompt-caching-2024-07-31" | :"computer-use-2024-10-22" | 25 more`

    - `:"message-batches-2024-09-24"`

    - `:"prompt-caching-2024-07-31"`

    - `:"computer-use-2024-10-22"`

    - `:"computer-use-2025-01-24"`

    - `:"pdfs-2024-09-25"`

    - `:"token-counting-2024-11-01"`

    - `:"token-efficient-tools-2025-02-19"`

    - `:"output-128k-2025-02-19"`

    - `:"files-api-2025-04-14"`

    - `:"mcp-client-2025-04-04"`

    - `:"mcp-client-2025-11-20"`

    - `:"dev-full-thinking-2025-05-14"`

    - `:"interleaved-thinking-2025-05-14"`

    - `:"code-execution-2025-05-22"`

    - `:"extended-cache-ttl-2025-04-11"`

    - `:"context-1m-2025-08-07"`

    - `:"context-management-2025-06-27"`

    - `:"model-context-window-exceeded-2025-08-26"`

    - `:"skills-2025-10-02"`

    - `:"fast-mode-2026-02-01"`

    - `:"output-300k-2026-03-24"`

    - `:"user-profiles-2026-03-24"`

    - `:"advisor-tool-2026-03-01"`

    - `:"managed-agents-2026-04-01"`

    - `:"cache-diagnosis-2026-04-07"`

    - `:"thinking-token-count-2026-05-13"`

    - `:"server-side-fallback-2026-06-01"`

    - `:"fallback-credit-2026-06-01"`

### Returns

- `BetaManagedAgentsSessionEvent = BetaManagedAgentsUserMessageEvent | BetaManagedAgentsUserInterruptEvent | BetaManagedAgentsUserToolConfirmationEvent | 31 more`

  Union type for all event types in a session.

  - `class BetaManagedAgentsUserMessageEvent`

    A user message event in the session conversation.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock]`

      Array of content blocks comprising the user message.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

        - `text: String`

          The text content.

        - `type: :text`

          - `:text`

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

        - `source: BetaManagedAgentsBase64ImageSource | BetaManagedAgentsURLImageSource | BetaManagedAgentsFileImageSource`

          Union type for image source variants.

          - `class BetaManagedAgentsBase64ImageSource`

            Base64-encoded image data.

            - `data: String`

              Base64-encoded image data.

            - `media_type: String`

              MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

            - `type: :base64`

              - `:base64`

          - `class BetaManagedAgentsURLImageSource`

            Image referenced by URL.

            - `type: :url`

              - `:url`

            - `url: String`

              URL of the image to fetch.

          - `class BetaManagedAgentsFileImageSource`

            Image referenced by file ID.

            - `file_id: String`

              ID of a previously uploaded file.

            - `type: :file`

              - `:file`

        - `type: :image`

          - `:image`

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `source: BetaManagedAgentsBase64DocumentSource | BetaManagedAgentsPlainTextDocumentSource | BetaManagedAgentsURLDocumentSource | BetaManagedAgentsFileDocumentSource`

          Union type for document source variants.

          - `class BetaManagedAgentsBase64DocumentSource`

            Base64-encoded document data.

            - `data: String`

              Base64-encoded document data.

            - `media_type: String`

              MIME type of the document (e.g., "application/pdf").

            - `type: :base64`

              - `:base64`

          - `class BetaManagedAgentsPlainTextDocumentSource`

            Plain text document content.

            - `data: String`

              The plain text content.

            - `media_type: :"text/plain"`

              MIME type of the text content. Must be "text/plain".

              - `:"text/plain"`

            - `type: :text`

              - `:text`

          - `class BetaManagedAgentsURLDocumentSource`

            Document referenced by URL.

            - `type: :url`

              - `:url`

            - `url: String`

              URL of the document to fetch.

          - `class BetaManagedAgentsFileDocumentSource`

            Document referenced by file ID.

            - `file_id: String`

              ID of a previously uploaded file.

            - `type: :file`

              - `:file`

        - `type: :document`

          - `:document`

        - `context: String`

          Additional context about the document for the model.

        - `title: String`

          The title of the document.

    - `type: :"user.message"`

      - `:"user.message"`

    - `processed_at: Time`

      A timestamp in RFC 3339 format

  - `class BetaManagedAgentsUserInterruptEvent`

    An interrupt event that pauses agent execution and returns control to the user.

    - `id: String`

      Unique identifier for this event.

    - `type: :"user.interrupt"`

      - `:"user.interrupt"`

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

  - `class BetaManagedAgentsUserToolConfirmationEvent`

    A tool confirmation event that approves or denies a pending tool execution.

    - `id: String`

      Unique identifier for this event.

    - `result: :allow | :deny`

      UserToolConfirmationResult enum

      - `:allow`

      - `:deny`

    - `tool_use_id: String`

      The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: :"user.tool_confirmation"`

      - `:"user.tool_confirmation"`

    - `deny_message: String`

      Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

  - `class BetaManagedAgentsUserCustomToolResultEvent`

    Event sent by the client providing the result of a custom tool execution.

    - `id: String`

      Unique identifier for this event.

    - `custom_tool_use_id: String`

      The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: :"user.custom_tool_result"`

      - `:"user.custom_tool_result"`

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock | BetaManagedAgentsSearchResultBlock]`

      The result content returned by the tool.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `class BetaManagedAgentsSearchResultBlock`

        A block containing a web search result.

        - `citations: BetaManagedAgentsSearchResultCitations`

          Citation settings for a search result.

          - `enabled: bool`

            Whether citations are enabled for this search result.

        - `content: Array[BetaManagedAgentsSearchResultContent]`

          Array of text content blocks from the search result.

          - `text: String`

            The text content.

          - `type: :text`

            - `:text`

        - `source: String`

          The URL source of the search result.

        - `title: String`

          The title of the search result.

        - `type: :search_result`

          - `:search_result`

    - `is_error: bool`

      Whether the tool execution resulted in an error.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

  - `class BetaManagedAgentsAgentCustomToolUseEvent`

    Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

    - `id: String`

      Unique identifier for this event.

    - `input: Hash[Symbol, untyped]`

      Input parameters for the tool call.

    - `name: String`

      Name of the custom tool being called.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.custom_tool_use"`

      - `:"agent.custom_tool_use"`

    - `session_thread_id: String`

      When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

  - `class BetaManagedAgentsAgentMessageEvent`

    An agent response event in the session conversation.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsTextBlock]`

      Array of text blocks comprising the agent response.

      - `text: String`

        The text content.

      - `type: :text`

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.message"`

      - `:"agent.message"`

  - `class BetaManagedAgentsAgentThinkingEvent`

    Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.thinking"`

      - `:"agent.thinking"`

  - `class BetaManagedAgentsAgentMCPToolUseEvent`

    Event emitted when the agent invokes a tool provided by an MCP server.

    - `id: String`

      Unique identifier for this event.

    - `input: Hash[Symbol, untyped]`

      Input parameters for the tool call.

    - `mcp_server_name: String`

      Name of the MCP server providing the tool.

    - `name: String`

      Name of the MCP tool being used.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.mcp_tool_use"`

      - `:"agent.mcp_tool_use"`

    - `evaluated_permission: :allow | :ask | :deny`

      AgentEvaluatedPermission enum

      - `:allow`

      - `:ask`

      - `:deny`

    - `session_thread_id: String`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `class BetaManagedAgentsAgentMCPToolResultEvent`

    Event representing the result of an MCP tool execution.

    - `id: String`

      Unique identifier for this event.

    - `mcp_tool_use_id: String`

      The id of the `agent.mcp_tool_use` event this result corresponds to.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.mcp_tool_result"`

      - `:"agent.mcp_tool_result"`

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock | BetaManagedAgentsSearchResultBlock]`

      The result content returned by the tool.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `class BetaManagedAgentsSearchResultBlock`

        A block containing a web search result.

    - `is_error: bool`

      Whether the tool execution resulted in an error.

  - `class BetaManagedAgentsAgentToolUseEvent`

    Event emitted when the agent invokes a built-in agent tool.

    - `id: String`

      Unique identifier for this event.

    - `input: Hash[Symbol, untyped]`

      Input parameters for the tool call.

    - `name: String`

      Name of the agent tool being used.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.tool_use"`

      - `:"agent.tool_use"`

    - `evaluated_permission: :allow | :ask | :deny`

      AgentEvaluatedPermission enum

      - `:allow`

      - `:ask`

      - `:deny`

    - `session_thread_id: String`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `class BetaManagedAgentsAgentToolResultEvent`

    Event representing the result of an agent tool execution.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `tool_use_id: String`

      The id of the `agent.tool_use` event this result corresponds to.

    - `type: :"agent.tool_result"`

      - `:"agent.tool_result"`

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock | BetaManagedAgentsSearchResultBlock]`

      The result content returned by the tool.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `class BetaManagedAgentsSearchResultBlock`

        A block containing a web search result.

    - `is_error: bool`

      Whether the tool execution resulted in an error.

  - `class BetaManagedAgentsAgentThreadMessageReceivedEvent`

    Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock]`

      Message content blocks.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `from_session_thread_id: String`

      Public `sthr_` ID of the thread that sent the message.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.thread_message_received"`

      - `:"agent.thread_message_received"`

    - `from_agent_name: String`

      Name of the callable agent this message came from. Absent when received from the primary agent.

  - `class BetaManagedAgentsAgentThreadMessageSentEvent`

    Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock]`

      Message content blocks.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `to_session_thread_id: String`

      Public `sthr_` ID of the thread the message was sent to.

    - `type: :"agent.thread_message_sent"`

      - `:"agent.thread_message_sent"`

    - `to_agent_name: String`

      Name of the callable agent this message was sent to. Absent when sent to the primary agent.

  - `class BetaManagedAgentsAgentThreadContextCompactedEvent`

    Indicates that context compaction (summarization) occurred during the session.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.thread_context_compacted"`

      - `:"agent.thread_context_compacted"`

  - `class BetaManagedAgentsSessionErrorEvent`

    An error event indicating a problem occurred during session execution.

    - `id: String`

      Unique identifier for this event.

    - `error: BetaManagedAgentsUnknownError | BetaManagedAgentsModelOverloadedError | BetaManagedAgentsModelRateLimitedError | 5 more`

      An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

      - `class BetaManagedAgentsUnknownError`

        An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `type: :retrying`

              - `:retrying`

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `type: :exhausted`

              - `:exhausted`

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

            - `type: :terminal`

              - `:terminal`

        - `type: :unknown_error`

          - `:unknown_error`

      - `class BetaManagedAgentsModelOverloadedError`

        The model is currently overloaded. Emitted after automatic retries are exhausted.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :model_overloaded_error`

          - `:model_overloaded_error`

      - `class BetaManagedAgentsModelRateLimitedError`

        The model request was rate-limited.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :model_rate_limited_error`

          - `:model_rate_limited_error`

      - `class BetaManagedAgentsModelRequestFailedError`

        A model request failed for a reason other than overload or rate-limiting.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :model_request_failed_error`

          - `:model_request_failed_error`

      - `class BetaManagedAgentsMCPConnectionFailedError`

        Failed to connect to an MCP server.

        - `mcp_server_name: String`

          Name of the MCP server that failed to connect.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :mcp_connection_failed_error`

          - `:mcp_connection_failed_error`

      - `class BetaManagedAgentsMCPAuthenticationFailedError`

        Authentication to an MCP server failed.

        - `mcp_server_name: String`

          Name of the MCP server that failed authentication.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :mcp_authentication_failed_error`

          - `:mcp_authentication_failed_error`

      - `class BetaManagedAgentsBillingError`

        The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :billing_error`

          - `:billing_error`

      - `class BetaManagedAgentsCredentialHostUnreachableError`

        An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

        - `credential_id: String`

          ID of the affected credential.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :credential_host_unreachable_error`

          - `:credential_host_unreachable_error`

        - `vault_id: String`

          ID of the vault containing the affected credential.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.error"`

      - `:"session.error"`

  - `class BetaManagedAgentsSessionStatusRescheduledEvent`

    Indicates the session is recovering from an error state and is rescheduled for execution.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.status_rescheduled"`

      - `:"session.status_rescheduled"`

  - `class BetaManagedAgentsSessionStatusRunningEvent`

    Indicates the session is actively running and the agent is working.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.status_running"`

      - `:"session.status_running"`

  - `class BetaManagedAgentsSessionStatusIdleEvent`

    Indicates the agent has paused and is awaiting user input.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `stop_reason: BetaManagedAgentsSessionEndTurn | BetaManagedAgentsSessionRequiresAction | BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `class BetaManagedAgentsSessionEndTurn`

        The agent completed its turn naturally and is ready for the next user message.

        - `type: :end_turn`

          - `:end_turn`

      - `class BetaManagedAgentsSessionRequiresAction`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

        - `event_ids: Array[String]`

          The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

        - `type: :requires_action`

          - `:requires_action`

      - `class BetaManagedAgentsSessionRetriesExhausted`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

        - `type: :retries_exhausted`

          - `:retries_exhausted`

    - `type: :"session.status_idle"`

      - `:"session.status_idle"`

  - `class BetaManagedAgentsSessionStatusTerminatedEvent`

    Indicates the session has terminated, either due to an error or completion.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.status_terminated"`

      - `:"session.status_terminated"`

  - `class BetaManagedAgentsSessionThreadCreatedEvent`

    Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the callable agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public `sthr_` ID of the newly created thread.

    - `type: :"session.thread_created"`

      - `:"session.thread_created"`

  - `class BetaManagedAgentsSpanOutcomeEvaluationStartEvent`

    Emitted when an outcome evaluation cycle begins.

    - `id: String`

      Unique identifier for this event.

    - `iteration: Integer`

      0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

    - `outcome_id: String`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"span.outcome_evaluation_start"`

      - `:"span.outcome_evaluation_start"`

  - `class BetaManagedAgentsSpanOutcomeEvaluationEndEvent`

    Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

    - `id: String`

      Unique identifier for this event.

    - `explanation: String`

      Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

    - `iteration: Integer`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_evaluation_start_id: String`

      The id of the corresponding `span.outcome_evaluation_start` event.

    - `outcome_id: String`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `result: String`

      Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

    - `type: :"span.outcome_evaluation_end"`

      - `:"span.outcome_evaluation_end"`

    - `usage: BetaManagedAgentsSpanModelUsage`

      Token usage for a single model request.

      - `cache_creation_input_tokens: Integer`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: Integer`

        Tokens read from prompt cache in this request.

      - `input_tokens: Integer`

        Input tokens consumed by this request.

      - `output_tokens: Integer`

        Output tokens generated by this request.

      - `speed: :standard | :fast`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `:standard`

        - `:fast`

  - `class BetaManagedAgentsSpanModelRequestStartEvent`

    Emitted when a model request is initiated by the agent.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"span.model_request_start"`

      - `:"span.model_request_start"`

  - `class BetaManagedAgentsSpanModelRequestEndEvent`

    Emitted when a model request completes.

    - `id: String`

      Unique identifier for this event.

    - `is_error: bool`

      Whether the model request resulted in an error.

    - `model_request_start_id: String`

      The id of the corresponding `span.model_request_start` event.

    - `model_usage: BetaManagedAgentsSpanModelUsage`

      Token usage for a single model request.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"span.model_request_end"`

      - `:"span.model_request_end"`

  - `class BetaManagedAgentsSpanOutcomeEvaluationOngoingEvent`

    Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

    - `id: String`

      Unique identifier for this event.

    - `iteration: Integer`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_id: String`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"span.outcome_evaluation_ongoing"`

      - `:"span.outcome_evaluation_ongoing"`

  - `class BetaManagedAgentsUserDefineOutcomeEvent`

    Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

    - `id: String`

      Unique identifier for this event.

    - `description: String`

      What the agent should produce. Copied from the input event.

    - `max_iterations: Integer`

      Evaluate-then-revise cycles before giving up. Default 3, max 20.

    - `outcome_id: String`

      Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `rubric: BetaManagedAgentsFileRubric | BetaManagedAgentsTextRubric`

      Rubric for grading the quality of an outcome.

      - `class BetaManagedAgentsFileRubric`

        Rubric referenced by a file uploaded via the Files API.

        - `file_id: String`

          ID of the rubric file.

        - `type: :file`

          - `:file`

      - `class BetaManagedAgentsTextRubric`

        Rubric content provided inline as text.

        - `content: String`

          Rubric content. Plain text or markdown — the grader treats it as freeform text.

        - `type: :text`

          - `:text`

    - `type: :"user.define_outcome"`

      - `:"user.define_outcome"`

  - `class BetaManagedAgentsSessionDeletedEvent`

    Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.deleted"`

      - `:"session.deleted"`

  - `class BetaManagedAgentsSessionThreadStatusRunningEvent`

    A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public sthr_ ID of the thread that started running.

    - `type: :"session.thread_status_running"`

      - `:"session.thread_status_running"`

  - `class BetaManagedAgentsSessionThreadStatusIdleEvent`

    A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public sthr_ ID of the thread that went idle.

    - `stop_reason: BetaManagedAgentsSessionEndTurn | BetaManagedAgentsSessionRequiresAction | BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `class BetaManagedAgentsSessionEndTurn`

        The agent completed its turn naturally and is ready for the next user message.

      - `class BetaManagedAgentsSessionRequiresAction`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

      - `class BetaManagedAgentsSessionRetriesExhausted`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

    - `type: :"session.thread_status_idle"`

      - `:"session.thread_status_idle"`

  - `class BetaManagedAgentsSessionThreadStatusTerminatedEvent`

    A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public sthr_ ID of the thread that terminated.

    - `type: :"session.thread_status_terminated"`

      - `:"session.thread_status_terminated"`

  - `class BetaManagedAgentsUserToolResultEvent`

    Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

    - `id: String`

      Unique identifier for this event.

    - `tool_use_id: String`

      The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: :"user.tool_result"`

      - `:"user.tool_result"`

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock | BetaManagedAgentsSearchResultBlock]`

      The result content returned by the tool.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `class BetaManagedAgentsSearchResultBlock`

        A block containing a web search result.

    - `is_error: bool`

      Whether the tool execution resulted in an error.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

  - `class BetaManagedAgentsSessionThreadStatusRescheduledEvent`

    A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public sthr_ ID of the thread that is retrying.

    - `type: :"session.thread_status_rescheduled"`

      - `:"session.thread_status_rescheduled"`

  - `class BetaManagedAgentsSessionUpdatedEvent`

    Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.updated"`

      - `:"session.updated"`

    - `agent: BetaManagedAgentsSessionAgent`

      Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

      - `id: String`

      - `description: String`

      - `mcp_servers: Array[BetaManagedAgentsMCPServerURLDefinition]`

        - `name: String`

        - `type: :url`

          - `:url`

        - `url: String`

      - `model: BetaManagedAgentsModelConfig`

        Model identifier and configuration.

        - `id: BetaManagedAgentsModel`

          The model that will power your agent.

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

          - `BetaManagedAgentsModel = :"claude-fable-5" | :"claude-opus-4-8" | :"claude-opus-4-7" | 8 more`

            The model that will power your agent.

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

            - `:"claude-fable-5"`

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

            - `:"claude-opus-4-8"`

              Frontier intelligence for long-running agents and coding

            - `:"claude-opus-4-7"`

              Frontier intelligence for long-running agents and coding

            - `:"claude-opus-4-6"`

              Most intelligent model for building agents and coding

            - `:"claude-sonnet-4-6"`

              Best combination of speed and intelligence

            - `:"claude-haiku-4-5"`

              Fastest model with near-frontier intelligence

            - `:"claude-haiku-4-5-20251001"`

              Fastest model with near-frontier intelligence

            - `:"claude-opus-4-5"`

              Premium model combining maximum intelligence with practical performance

            - `:"claude-opus-4-5-20251101"`

              Premium model combining maximum intelligence with practical performance

            - `:"claude-sonnet-4-5"`

              High-performance model for agents and coding

            - `:"claude-sonnet-4-5-20250929"`

              High-performance model for agents and coding

          - `String = String`

        - `speed: :standard | :fast`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `:standard`

          - `:fast`

      - `multiagent: BetaManagedAgentsSessionMultiagentCoordinator`

        Resolved coordinator topology with full agent definitions for each roster member.

        - `agents: Array[BetaManagedAgentsSessionThreadAgent]`

          Full `agent` definitions the coordinator may spawn as session threads.

          - `id: String`

          - `description: String`

          - `mcp_servers: Array[BetaManagedAgentsMCPServerURLDefinition]`

            - `name: String`

            - `type: :url`

            - `url: String`

          - `model: BetaManagedAgentsModelConfig`

            Model identifier and configuration.

          - `name: String`

          - `skills: Array[BetaManagedAgentsAnthropicSkill | BetaManagedAgentsCustomSkill]`

            - `class BetaManagedAgentsAnthropicSkill`

              A resolved Anthropic-managed skill.

              - `skill_id: String`

              - `type: :anthropic`

                - `:anthropic`

              - `version: String`

            - `class BetaManagedAgentsCustomSkill`

              A resolved user-created custom skill.

              - `skill_id: String`

              - `type: :custom`

                - `:custom`

              - `version: String`

          - `system_: String`

          - `tools: Array[BetaManagedAgentsAgentToolset20260401 | BetaManagedAgentsMCPToolset | BetaManagedAgentsCustomTool]`

            - `class BetaManagedAgentsAgentToolset20260401`

              - `configs: Array[BetaManagedAgentsAgentToolConfig]`

                - `enabled: bool`

                - `name: :bash | :edit | :read | 5 more`

                  Built-in agent tool identifier.

                  - `:bash`

                  - `:edit`

                  - `:read`

                  - `:write`

                  - `:glob`

                  - `:grep`

                  - `:web_fetch`

                  - `:web_search`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy | BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `class BetaManagedAgentsAlwaysAllowPolicy`

                    Tool calls are automatically approved without user confirmation.

                    - `type: :always_allow`

                      - `:always_allow`

                  - `class BetaManagedAgentsAlwaysAskPolicy`

                    Tool calls require user confirmation before execution.

                    - `type: :always_ask`

                      - `:always_ask`

              - `default_config: BetaManagedAgentsAgentToolsetDefaultConfig`

                Resolved default configuration for agent tools.

                - `enabled: bool`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy | BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `class BetaManagedAgentsAlwaysAllowPolicy`

                    Tool calls are automatically approved without user confirmation.

                  - `class BetaManagedAgentsAlwaysAskPolicy`

                    Tool calls require user confirmation before execution.

              - `type: :agent_toolset_20260401`

                - `:agent_toolset_20260401`

            - `class BetaManagedAgentsMCPToolset`

              - `configs: Array[BetaManagedAgentsMCPToolConfig]`

                - `enabled: bool`

                - `name: String`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy | BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `class BetaManagedAgentsAlwaysAllowPolicy`

                    Tool calls are automatically approved without user confirmation.

                  - `class BetaManagedAgentsAlwaysAskPolicy`

                    Tool calls require user confirmation before execution.

              - `default_config: BetaManagedAgentsMCPToolsetDefaultConfig`

                Resolved default configuration for all tools from an MCP server.

                - `enabled: bool`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy | BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `class BetaManagedAgentsAlwaysAllowPolicy`

                    Tool calls are automatically approved without user confirmation.

                  - `class BetaManagedAgentsAlwaysAskPolicy`

                    Tool calls require user confirmation before execution.

              - `mcp_server_name: String`

              - `type: :mcp_toolset`

                - `:mcp_toolset`

            - `class BetaManagedAgentsCustomTool`

              A custom tool as returned in API responses.

              - `description: String`

              - `input_schema: BetaManagedAgentsCustomToolInputSchema`

                JSON Schema for custom tool input parameters.

                - `type: :object`

                  - `:object`

                - `properties: Hash[Symbol, untyped]`

                - `required: Array[String]`

              - `name: String`

              - `type: :custom`

                - `:custom`

          - `type: :agent`

            - `:agent`

          - `version: Integer`

        - `type: :coordinator`

          - `:coordinator`

      - `name: String`

      - `skills: Array[BetaManagedAgentsAnthropicSkill | BetaManagedAgentsCustomSkill]`

        - `class BetaManagedAgentsAnthropicSkill`

          A resolved Anthropic-managed skill.

        - `class BetaManagedAgentsCustomSkill`

          A resolved user-created custom skill.

      - `system_: String`

      - `tools: Array[BetaManagedAgentsAgentToolset20260401 | BetaManagedAgentsMCPToolset | BetaManagedAgentsCustomTool]`

        - `class BetaManagedAgentsAgentToolset20260401`

        - `class BetaManagedAgentsMCPToolset`

        - `class BetaManagedAgentsCustomTool`

          A custom tool as returned in API responses.

      - `type: :agent`

        - `:agent`

      - `version: Integer`

    - `metadata: Hash[Symbol, String]`

      The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

    - `title: String`

      The session's new title. Present only when the update changed it.

  - `class BetaManagedAgentsSystemMessageEvent`

    A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsSystemContentBlock]`

      System content blocks. Text-only.

      - `text: String`

        The text content.

      - `type: :text`

        - `:text`

    - `type: :"system.message"`

      - `:"system.message"`

    - `processed_at: Time`

      A timestamp in RFC 3339 format

### Example

```ruby
require "anthropic"

anthropic = Anthropic::Client.new(api_key: "my-anthropic-api-key")

page = anthropic.beta.sessions.threads.events.list(
  "sthr_011CZkZVWa6oIjw0rgXZpnBt",
  session_id: "sesn_011CZkZAtmR3yMPDzynEDxu7"
)

puts(page)
```

#### Response

```json
{
  "data": [
    {
      "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
      "content": [
        {
          "text": "Where is my order #1234?",
          "type": "text"
        }
      ],
      "type": "user.message",
      "processed_at": "2026-03-15T10:00:00Z"
    }
  ],
  "next_page": "next_page"
}
```

## Stream Session Thread Events

`beta.sessions.threads.events.stream(thread_id, **kwargs) -> BetaManagedAgentsStreamSessionThreadEvents`

**get** `/v1/sessions/{session_id}/threads/{thread_id}/stream`

Stream Session Thread Events

### Parameters

- `session_id: String`

- `thread_id: String`

- `betas: Array[AnthropicBeta]`

  Optional header to specify the beta version(s) you want to use.

  - `String = String`

  - `AnthropicBeta = :"message-batches-2024-09-24" | :"prompt-caching-2024-07-31" | :"computer-use-2024-10-22" | 25 more`

    - `:"message-batches-2024-09-24"`

    - `:"prompt-caching-2024-07-31"`

    - `:"computer-use-2024-10-22"`

    - `:"computer-use-2025-01-24"`

    - `:"pdfs-2024-09-25"`

    - `:"token-counting-2024-11-01"`

    - `:"token-efficient-tools-2025-02-19"`

    - `:"output-128k-2025-02-19"`

    - `:"files-api-2025-04-14"`

    - `:"mcp-client-2025-04-04"`

    - `:"mcp-client-2025-11-20"`

    - `:"dev-full-thinking-2025-05-14"`

    - `:"interleaved-thinking-2025-05-14"`

    - `:"code-execution-2025-05-22"`

    - `:"extended-cache-ttl-2025-04-11"`

    - `:"context-1m-2025-08-07"`

    - `:"context-management-2025-06-27"`

    - `:"model-context-window-exceeded-2025-08-26"`

    - `:"skills-2025-10-02"`

    - `:"fast-mode-2026-02-01"`

    - `:"output-300k-2026-03-24"`

    - `:"user-profiles-2026-03-24"`

    - `:"advisor-tool-2026-03-01"`

    - `:"managed-agents-2026-04-01"`

    - `:"cache-diagnosis-2026-04-07"`

    - `:"thinking-token-count-2026-05-13"`

    - `:"server-side-fallback-2026-06-01"`

    - `:"fallback-credit-2026-06-01"`

### Returns

- `BetaManagedAgentsStreamSessionThreadEvents = BetaManagedAgentsUserMessageEvent | BetaManagedAgentsUserInterruptEvent | BetaManagedAgentsUserToolConfirmationEvent | 31 more`

  Server-sent event in a single thread's stream.

  - `class BetaManagedAgentsUserMessageEvent`

    A user message event in the session conversation.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock]`

      Array of content blocks comprising the user message.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

        - `text: String`

          The text content.

        - `type: :text`

          - `:text`

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

        - `source: BetaManagedAgentsBase64ImageSource | BetaManagedAgentsURLImageSource | BetaManagedAgentsFileImageSource`

          Union type for image source variants.

          - `class BetaManagedAgentsBase64ImageSource`

            Base64-encoded image data.

            - `data: String`

              Base64-encoded image data.

            - `media_type: String`

              MIME type of the image (e.g., "image/png", "image/jpeg", "image/gif", "image/webp").

            - `type: :base64`

              - `:base64`

          - `class BetaManagedAgentsURLImageSource`

            Image referenced by URL.

            - `type: :url`

              - `:url`

            - `url: String`

              URL of the image to fetch.

          - `class BetaManagedAgentsFileImageSource`

            Image referenced by file ID.

            - `file_id: String`

              ID of a previously uploaded file.

            - `type: :file`

              - `:file`

        - `type: :image`

          - `:image`

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

        - `source: BetaManagedAgentsBase64DocumentSource | BetaManagedAgentsPlainTextDocumentSource | BetaManagedAgentsURLDocumentSource | BetaManagedAgentsFileDocumentSource`

          Union type for document source variants.

          - `class BetaManagedAgentsBase64DocumentSource`

            Base64-encoded document data.

            - `data: String`

              Base64-encoded document data.

            - `media_type: String`

              MIME type of the document (e.g., "application/pdf").

            - `type: :base64`

              - `:base64`

          - `class BetaManagedAgentsPlainTextDocumentSource`

            Plain text document content.

            - `data: String`

              The plain text content.

            - `media_type: :"text/plain"`

              MIME type of the text content. Must be "text/plain".

              - `:"text/plain"`

            - `type: :text`

              - `:text`

          - `class BetaManagedAgentsURLDocumentSource`

            Document referenced by URL.

            - `type: :url`

              - `:url`

            - `url: String`

              URL of the document to fetch.

          - `class BetaManagedAgentsFileDocumentSource`

            Document referenced by file ID.

            - `file_id: String`

              ID of a previously uploaded file.

            - `type: :file`

              - `:file`

        - `type: :document`

          - `:document`

        - `context: String`

          Additional context about the document for the model.

        - `title: String`

          The title of the document.

    - `type: :"user.message"`

      - `:"user.message"`

    - `processed_at: Time`

      A timestamp in RFC 3339 format

  - `class BetaManagedAgentsUserInterruptEvent`

    An interrupt event that pauses agent execution and returns control to the user.

    - `id: String`

      Unique identifier for this event.

    - `type: :"user.interrupt"`

      - `:"user.interrupt"`

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      If absent, interrupts every non-archived thread in a multiagent session (or the primary alone in a single-agent session). If present, interrupts only the named thread.

  - `class BetaManagedAgentsUserToolConfirmationEvent`

    A tool confirmation event that approves or denies a pending tool execution.

    - `id: String`

      Unique identifier for this event.

    - `result: :allow | :deny`

      UserToolConfirmationResult enum

      - `:allow`

      - `:deny`

    - `tool_use_id: String`

      The id of the `agent.tool_use` or `agent.mcp_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: :"user.tool_confirmation"`

      - `:"user.tool_confirmation"`

    - `deny_message: String`

      Optional message providing context for a 'deny' decision. Only allowed when result is 'deny'.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      When set, the confirmation routes to this subagent's thread rather than the primary. Echo this from the `session_thread_id` on the `agent.tool_use` or `agent.mcp_tool_use` event that prompted the approval.

  - `class BetaManagedAgentsUserCustomToolResultEvent`

    Event sent by the client providing the result of a custom tool execution.

    - `id: String`

      Unique identifier for this event.

    - `custom_tool_use_id: String`

      The id of the `agent.custom_tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: :"user.custom_tool_result"`

      - `:"user.custom_tool_result"`

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock | BetaManagedAgentsSearchResultBlock]`

      The result content returned by the tool.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `class BetaManagedAgentsSearchResultBlock`

        A block containing a web search result.

        - `citations: BetaManagedAgentsSearchResultCitations`

          Citation settings for a search result.

          - `enabled: bool`

            Whether citations are enabled for this search result.

        - `content: Array[BetaManagedAgentsSearchResultContent]`

          Array of text content blocks from the search result.

          - `text: String`

            The text content.

          - `type: :text`

            - `:text`

        - `source: String`

          The URL source of the search result.

        - `title: String`

          The title of the search result.

        - `type: :search_result`

          - `:search_result`

    - `is_error: bool`

      Whether the tool execution resulted in an error.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Routes this result to a subagent thread. Copy from the `agent.custom_tool_use` event's `session_thread_id`.

  - `class BetaManagedAgentsAgentCustomToolUseEvent`

    Event emitted when the agent calls a custom tool. The session goes idle until the client sends a `user.custom_tool_result` event with the result.

    - `id: String`

      Unique identifier for this event.

    - `input: Hash[Symbol, untyped]`

      Input parameters for the tool call.

    - `name: String`

      Name of the custom tool being called.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.custom_tool_use"`

      - `:"agent.custom_tool_use"`

    - `session_thread_id: String`

      When set, this event was cross-posted from a subagent's thread to surface its custom tool use on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.custom_tool_result` event to route the result back.

  - `class BetaManagedAgentsAgentMessageEvent`

    An agent response event in the session conversation.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsTextBlock]`

      Array of text blocks comprising the agent response.

      - `text: String`

        The text content.

      - `type: :text`

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.message"`

      - `:"agent.message"`

  - `class BetaManagedAgentsAgentThinkingEvent`

    Indicates the agent is making forward progress via extended thinking. A progress signal, not a content carrier.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.thinking"`

      - `:"agent.thinking"`

  - `class BetaManagedAgentsAgentMCPToolUseEvent`

    Event emitted when the agent invokes a tool provided by an MCP server.

    - `id: String`

      Unique identifier for this event.

    - `input: Hash[Symbol, untyped]`

      Input parameters for the tool call.

    - `mcp_server_name: String`

      Name of the MCP server providing the tool.

    - `name: String`

      Name of the MCP tool being used.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.mcp_tool_use"`

      - `:"agent.mcp_tool_use"`

    - `evaluated_permission: :allow | :ask | :deny`

      AgentEvaluatedPermission enum

      - `:allow`

      - `:ask`

      - `:deny`

    - `session_thread_id: String`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `class BetaManagedAgentsAgentMCPToolResultEvent`

    Event representing the result of an MCP tool execution.

    - `id: String`

      Unique identifier for this event.

    - `mcp_tool_use_id: String`

      The id of the `agent.mcp_tool_use` event this result corresponds to.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.mcp_tool_result"`

      - `:"agent.mcp_tool_result"`

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock | BetaManagedAgentsSearchResultBlock]`

      The result content returned by the tool.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `class BetaManagedAgentsSearchResultBlock`

        A block containing a web search result.

    - `is_error: bool`

      Whether the tool execution resulted in an error.

  - `class BetaManagedAgentsAgentToolUseEvent`

    Event emitted when the agent invokes a built-in agent tool.

    - `id: String`

      Unique identifier for this event.

    - `input: Hash[Symbol, untyped]`

      Input parameters for the tool call.

    - `name: String`

      Name of the agent tool being used.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.tool_use"`

      - `:"agent.tool_use"`

    - `evaluated_permission: :allow | :ask | :deny`

      AgentEvaluatedPermission enum

      - `:allow`

      - `:ask`

      - `:deny`

    - `session_thread_id: String`

      When set, this event was cross-posted from a subagent's thread to surface its permission request on the primary thread's stream. Empty on the thread's own events. Echo this on a `user.tool_confirmation` event to route the approval back.

  - `class BetaManagedAgentsAgentToolResultEvent`

    Event representing the result of an agent tool execution.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `tool_use_id: String`

      The id of the `agent.tool_use` event this result corresponds to.

    - `type: :"agent.tool_result"`

      - `:"agent.tool_result"`

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock | BetaManagedAgentsSearchResultBlock]`

      The result content returned by the tool.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `class BetaManagedAgentsSearchResultBlock`

        A block containing a web search result.

    - `is_error: bool`

      Whether the tool execution resulted in an error.

  - `class BetaManagedAgentsAgentThreadMessageReceivedEvent`

    Delivery event written to the target thread's input stream when an agent-to-agent message arrives.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock]`

      Message content blocks.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `from_session_thread_id: String`

      Public `sthr_` ID of the thread that sent the message.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.thread_message_received"`

      - `:"agent.thread_message_received"`

    - `from_agent_name: String`

      Name of the callable agent this message came from. Absent when received from the primary agent.

  - `class BetaManagedAgentsAgentThreadMessageSentEvent`

    Observability event emitted to the sender's output stream when an agent-to-agent message is sent.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock]`

      Message content blocks.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `to_session_thread_id: String`

      Public `sthr_` ID of the thread the message was sent to.

    - `type: :"agent.thread_message_sent"`

      - `:"agent.thread_message_sent"`

    - `to_agent_name: String`

      Name of the callable agent this message was sent to. Absent when sent to the primary agent.

  - `class BetaManagedAgentsAgentThreadContextCompactedEvent`

    Indicates that context compaction (summarization) occurred during the session.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"agent.thread_context_compacted"`

      - `:"agent.thread_context_compacted"`

  - `class BetaManagedAgentsSessionErrorEvent`

    An error event indicating a problem occurred during session execution.

    - `id: String`

      Unique identifier for this event.

    - `error: BetaManagedAgentsUnknownError | BetaManagedAgentsModelOverloadedError | BetaManagedAgentsModelRateLimitedError | 5 more`

      An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

      - `class BetaManagedAgentsUnknownError`

        An unknown or unexpected error occurred during session execution. A fallback variant; clients that don't recognize a new error code can match on `retry_status` and `message` alone.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

            - `type: :retrying`

              - `:retrying`

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

            - `type: :exhausted`

              - `:exhausted`

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

            - `type: :terminal`

              - `:terminal`

        - `type: :unknown_error`

          - `:unknown_error`

      - `class BetaManagedAgentsModelOverloadedError`

        The model is currently overloaded. Emitted after automatic retries are exhausted.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :model_overloaded_error`

          - `:model_overloaded_error`

      - `class BetaManagedAgentsModelRateLimitedError`

        The model request was rate-limited.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :model_rate_limited_error`

          - `:model_rate_limited_error`

      - `class BetaManagedAgentsModelRequestFailedError`

        A model request failed for a reason other than overload or rate-limiting.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :model_request_failed_error`

          - `:model_request_failed_error`

      - `class BetaManagedAgentsMCPConnectionFailedError`

        Failed to connect to an MCP server.

        - `mcp_server_name: String`

          Name of the MCP server that failed to connect.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :mcp_connection_failed_error`

          - `:mcp_connection_failed_error`

      - `class BetaManagedAgentsMCPAuthenticationFailedError`

        Authentication to an MCP server failed.

        - `mcp_server_name: String`

          Name of the MCP server that failed authentication.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :mcp_authentication_failed_error`

          - `:mcp_authentication_failed_error`

      - `class BetaManagedAgentsBillingError`

        The caller's organization or workspace cannot make model requests — out of credits or spend limit reached. Retrying with the same credentials will not succeed; the caller must resolve the billing state.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :billing_error`

          - `:billing_error`

      - `class BetaManagedAgentsCredentialHostUnreachableError`

        An `environment_variable` credential's `auth.networking.allowed_hosts` includes a host the environment's network policy does not permit.

        - `credential_id: String`

          ID of the affected credential.

        - `message: String`

          Human-readable error description.

        - `retry_status: BetaManagedAgentsRetryStatusRetrying | BetaManagedAgentsRetryStatusExhausted | BetaManagedAgentsRetryStatusTerminal`

          What the client should do next in response to this error.

          - `class BetaManagedAgentsRetryStatusRetrying`

            The server is retrying automatically. Client should wait; the same error type may fire again as retrying, then once as exhausted when the retry budget runs out.

          - `class BetaManagedAgentsRetryStatusExhausted`

            This turn is dead; queued inputs are flushed and the session returns to idle. Client may send a new prompt.

          - `class BetaManagedAgentsRetryStatusTerminal`

            The session encountered a terminal error and will transition to `terminated` state.

        - `type: :credential_host_unreachable_error`

          - `:credential_host_unreachable_error`

        - `vault_id: String`

          ID of the vault containing the affected credential.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.error"`

      - `:"session.error"`

  - `class BetaManagedAgentsSessionStatusRescheduledEvent`

    Indicates the session is recovering from an error state and is rescheduled for execution.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.status_rescheduled"`

      - `:"session.status_rescheduled"`

  - `class BetaManagedAgentsSessionStatusRunningEvent`

    Indicates the session is actively running and the agent is working.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.status_running"`

      - `:"session.status_running"`

  - `class BetaManagedAgentsSessionStatusIdleEvent`

    Indicates the agent has paused and is awaiting user input.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `stop_reason: BetaManagedAgentsSessionEndTurn | BetaManagedAgentsSessionRequiresAction | BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `class BetaManagedAgentsSessionEndTurn`

        The agent completed its turn naturally and is ready for the next user message.

        - `type: :end_turn`

          - `:end_turn`

      - `class BetaManagedAgentsSessionRequiresAction`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

        - `event_ids: Array[String]`

          The ids of events the agent is blocked on. Resolving fewer than all re-emits `session.status_idle` with the remainder.

        - `type: :requires_action`

          - `:requires_action`

      - `class BetaManagedAgentsSessionRetriesExhausted`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

        - `type: :retries_exhausted`

          - `:retries_exhausted`

    - `type: :"session.status_idle"`

      - `:"session.status_idle"`

  - `class BetaManagedAgentsSessionStatusTerminatedEvent`

    Indicates the session has terminated, either due to an error or completion.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.status_terminated"`

      - `:"session.status_terminated"`

  - `class BetaManagedAgentsSessionThreadCreatedEvent`

    Emitted when a subagent is spawned as a new thread. Written to the parent thread's output stream so clients observing the session see child creation.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the callable agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public `sthr_` ID of the newly created thread.

    - `type: :"session.thread_created"`

      - `:"session.thread_created"`

  - `class BetaManagedAgentsSpanOutcomeEvaluationStartEvent`

    Emitted when an outcome evaluation cycle begins.

    - `id: String`

      Unique identifier for this event.

    - `iteration: Integer`

      0-indexed revision cycle. 0 is the first evaluation; 1 is the re-evaluation after the first revision; etc.

    - `outcome_id: String`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"span.outcome_evaluation_start"`

      - `:"span.outcome_evaluation_start"`

  - `class BetaManagedAgentsSpanOutcomeEvaluationEndEvent`

    Emitted when an outcome evaluation cycle completes. Carries the verdict and aggregate token usage. A verdict of `needs_revision` means another evaluation cycle follows; `satisfied`, `max_iterations_reached`, `failed`, or `interrupted` are terminal — no further evaluation cycles follow.

    - `id: String`

      Unique identifier for this event.

    - `explanation: String`

      Human-readable explanation of the verdict. For `needs_revision`, describes which criteria failed and why.

    - `iteration: Integer`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_evaluation_start_id: String`

      The id of the corresponding `span.outcome_evaluation_start` event.

    - `outcome_id: String`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `result: String`

      Evaluation verdict. 'satisfied': criteria met, session goes idle. 'needs_revision': criteria not met, another revision cycle follows. 'max_iterations_reached': evaluation budget exhausted with criteria still unmet — one final acknowledgment turn follows before the session goes idle, but no further evaluation runs. 'failed': grader determined the rubric does not apply to the deliverables. 'interrupted': user sent an interrupt while evaluation was in progress.

    - `type: :"span.outcome_evaluation_end"`

      - `:"span.outcome_evaluation_end"`

    - `usage: BetaManagedAgentsSpanModelUsage`

      Token usage for a single model request.

      - `cache_creation_input_tokens: Integer`

        Tokens used to create prompt cache in this request.

      - `cache_read_input_tokens: Integer`

        Tokens read from prompt cache in this request.

      - `input_tokens: Integer`

        Input tokens consumed by this request.

      - `output_tokens: Integer`

        Output tokens generated by this request.

      - `speed: :standard | :fast`

        Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

        - `:standard`

        - `:fast`

  - `class BetaManagedAgentsSpanModelRequestStartEvent`

    Emitted when a model request is initiated by the agent.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"span.model_request_start"`

      - `:"span.model_request_start"`

  - `class BetaManagedAgentsSpanModelRequestEndEvent`

    Emitted when a model request completes.

    - `id: String`

      Unique identifier for this event.

    - `is_error: bool`

      Whether the model request resulted in an error.

    - `model_request_start_id: String`

      The id of the corresponding `span.model_request_start` event.

    - `model_usage: BetaManagedAgentsSpanModelUsage`

      Token usage for a single model request.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"span.model_request_end"`

      - `:"span.model_request_end"`

  - `class BetaManagedAgentsSpanOutcomeEvaluationOngoingEvent`

    Periodic heartbeat emitted while an outcome evaluation cycle is in progress. Distinguishes 'evaluation is actively running' from 'evaluation is stuck' between the corresponding `span.outcome_evaluation_start` and `span.outcome_evaluation_end` events.

    - `id: String`

      Unique identifier for this event.

    - `iteration: Integer`

      0-indexed revision cycle, matching the corresponding `span.outcome_evaluation_start`.

    - `outcome_id: String`

      The `outc_` ID of the outcome being evaluated.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"span.outcome_evaluation_ongoing"`

      - `:"span.outcome_evaluation_ongoing"`

  - `class BetaManagedAgentsUserDefineOutcomeEvent`

    Echo of a `user.define_outcome` input event. Carries the server-generated `outcome_id` that subsequent `span.outcome_evaluation_*` events reference.

    - `id: String`

      Unique identifier for this event.

    - `description: String`

      What the agent should produce. Copied from the input event.

    - `max_iterations: Integer`

      Evaluate-then-revise cycles before giving up. Default 3, max 20.

    - `outcome_id: String`

      Server-generated `outc_` ID for this outcome. Referenced by `span.outcome_evaluation_*` events and the session's `outcome_evaluations` list.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `rubric: BetaManagedAgentsFileRubric | BetaManagedAgentsTextRubric`

      Rubric for grading the quality of an outcome.

      - `class BetaManagedAgentsFileRubric`

        Rubric referenced by a file uploaded via the Files API.

        - `file_id: String`

          ID of the rubric file.

        - `type: :file`

          - `:file`

      - `class BetaManagedAgentsTextRubric`

        Rubric content provided inline as text.

        - `content: String`

          Rubric content. Plain text or markdown — the grader treats it as freeform text.

        - `type: :text`

          - `:text`

    - `type: :"user.define_outcome"`

      - `:"user.define_outcome"`

  - `class BetaManagedAgentsSessionDeletedEvent`

    Emitted when a session has been deleted. Terminates any active event stream — no further events will be emitted for this session.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.deleted"`

      - `:"session.deleted"`

  - `class BetaManagedAgentsSessionThreadStatusRunningEvent`

    A session thread has begun executing. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public sthr_ ID of the thread that started running.

    - `type: :"session.thread_status_running"`

      - `:"session.thread_status_running"`

  - `class BetaManagedAgentsSessionThreadStatusIdleEvent`

    A session thread has yielded and is awaiting input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public sthr_ ID of the thread that went idle.

    - `stop_reason: BetaManagedAgentsSessionEndTurn | BetaManagedAgentsSessionRequiresAction | BetaManagedAgentsSessionRetriesExhausted`

      The agent completed its turn naturally and is ready for the next user message.

      - `class BetaManagedAgentsSessionEndTurn`

        The agent completed its turn naturally and is ready for the next user message.

      - `class BetaManagedAgentsSessionRequiresAction`

        The agent is idle waiting on one or more blocking user-input events (tool confirmation, custom tool result, etc.). Resolving all of them transitions the session back to running.

      - `class BetaManagedAgentsSessionRetriesExhausted`

        The turn ended because the retry budget was exhausted (`max_iterations` hit or an error escalated to `retry_status: 'exhausted'`).

    - `type: :"session.thread_status_idle"`

      - `:"session.thread_status_idle"`

  - `class BetaManagedAgentsSessionThreadStatusTerminatedEvent`

    A session thread has terminated and will accept no further input. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public sthr_ ID of the thread that terminated.

    - `type: :"session.thread_status_terminated"`

      - `:"session.thread_status_terminated"`

  - `class BetaManagedAgentsUserToolResultEvent`

    Event sent by the client providing the result of an agent-toolset tool execution. Only valid on `self_hosted` environments, where sandbox-routed tools are executed by the client rather than the server.

    - `id: String`

      Unique identifier for this event.

    - `tool_use_id: String`

      The id of the `agent.tool_use` event this result corresponds to, which can be found in the last `session.status_idle` [event's](https://platform.claude.com/docs/en/api/beta/sessions/events/list#beta_managed_agents_session_requires_action.event_ids) `stop_reason.event_ids` field.

    - `type: :"user.tool_result"`

      - `:"user.tool_result"`

    - `content: Array[BetaManagedAgentsTextBlock | BetaManagedAgentsImageBlock | BetaManagedAgentsDocumentBlock | BetaManagedAgentsSearchResultBlock]`

      The result content returned by the tool.

      - `class BetaManagedAgentsTextBlock`

        Regular text content.

      - `class BetaManagedAgentsImageBlock`

        Image content specified directly as base64 data or as a reference via a URL.

      - `class BetaManagedAgentsDocumentBlock`

        Document content, either specified directly as base64 data, as text, or as a reference via a URL.

      - `class BetaManagedAgentsSearchResultBlock`

        A block containing a web search result.

    - `is_error: bool`

      Whether the tool execution resulted in an error.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Routes this result to a subagent thread. Copy from the `agent.tool_use` event's `session_thread_id`.

  - `class BetaManagedAgentsSessionThreadStatusRescheduledEvent`

    A session thread hit a transient error and is retrying automatically. Emitted on the thread's own stream and cross-posted to the primary stream for child threads.

    - `id: String`

      Unique identifier for this event.

    - `agent_name: String`

      Name of the agent the thread runs.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `session_thread_id: String`

      Public sthr_ ID of the thread that is retrying.

    - `type: :"session.thread_status_rescheduled"`

      - `:"session.thread_status_rescheduled"`

  - `class BetaManagedAgentsSessionUpdatedEvent`

    Emitted when an UpdateSession request changed at least one field. Carries only the fields that changed; absent fields were not part of the update. The new configuration applies from the next turn.

    - `id: String`

      Unique identifier for this event.

    - `processed_at: Time`

      A timestamp in RFC 3339 format

    - `type: :"session.updated"`

      - `:"session.updated"`

    - `agent: BetaManagedAgentsSessionAgent`

      Resolved `agent` definition for a `session`. Snapshot of the `agent` at `session` creation time.

      - `id: String`

      - `description: String`

      - `mcp_servers: Array[BetaManagedAgentsMCPServerURLDefinition]`

        - `name: String`

        - `type: :url`

          - `:url`

        - `url: String`

      - `model: BetaManagedAgentsModelConfig`

        Model identifier and configuration.

        - `id: BetaManagedAgentsModel`

          The model that will power your agent.

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

          - `BetaManagedAgentsModel = :"claude-fable-5" | :"claude-opus-4-8" | :"claude-opus-4-7" | 8 more`

            The model that will power your agent.

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

            - `:"claude-fable-5"`

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

            - `:"claude-opus-4-8"`

              Frontier intelligence for long-running agents and coding

            - `:"claude-opus-4-7"`

              Frontier intelligence for long-running agents and coding

            - `:"claude-opus-4-6"`

              Most intelligent model for building agents and coding

            - `:"claude-sonnet-4-6"`

              Best combination of speed and intelligence

            - `:"claude-haiku-4-5"`

              Fastest model with near-frontier intelligence

            - `:"claude-haiku-4-5-20251001"`

              Fastest model with near-frontier intelligence

            - `:"claude-opus-4-5"`

              Premium model combining maximum intelligence with practical performance

            - `:"claude-opus-4-5-20251101"`

              Premium model combining maximum intelligence with practical performance

            - `:"claude-sonnet-4-5"`

              High-performance model for agents and coding

            - `:"claude-sonnet-4-5-20250929"`

              High-performance model for agents and coding

          - `String = String`

        - `speed: :standard | :fast`

          Inference speed mode. `fast` provides significantly faster output token generation at premium pricing. Not all models support `fast`; invalid combinations are rejected at create time.

          - `:standard`

          - `:fast`

      - `multiagent: BetaManagedAgentsSessionMultiagentCoordinator`

        Resolved coordinator topology with full agent definitions for each roster member.

        - `agents: Array[BetaManagedAgentsSessionThreadAgent]`

          Full `agent` definitions the coordinator may spawn as session threads.

          - `id: String`

          - `description: String`

          - `mcp_servers: Array[BetaManagedAgentsMCPServerURLDefinition]`

            - `name: String`

            - `type: :url`

            - `url: String`

          - `model: BetaManagedAgentsModelConfig`

            Model identifier and configuration.

          - `name: String`

          - `skills: Array[BetaManagedAgentsAnthropicSkill | BetaManagedAgentsCustomSkill]`

            - `class BetaManagedAgentsAnthropicSkill`

              A resolved Anthropic-managed skill.

              - `skill_id: String`

              - `type: :anthropic`

                - `:anthropic`

              - `version: String`

            - `class BetaManagedAgentsCustomSkill`

              A resolved user-created custom skill.

              - `skill_id: String`

              - `type: :custom`

                - `:custom`

              - `version: String`

          - `system_: String`

          - `tools: Array[BetaManagedAgentsAgentToolset20260401 | BetaManagedAgentsMCPToolset | BetaManagedAgentsCustomTool]`

            - `class BetaManagedAgentsAgentToolset20260401`

              - `configs: Array[BetaManagedAgentsAgentToolConfig]`

                - `enabled: bool`

                - `name: :bash | :edit | :read | 5 more`

                  Built-in agent tool identifier.

                  - `:bash`

                  - `:edit`

                  - `:read`

                  - `:write`

                  - `:glob`

                  - `:grep`

                  - `:web_fetch`

                  - `:web_search`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy | BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `class BetaManagedAgentsAlwaysAllowPolicy`

                    Tool calls are automatically approved without user confirmation.

                    - `type: :always_allow`

                      - `:always_allow`

                  - `class BetaManagedAgentsAlwaysAskPolicy`

                    Tool calls require user confirmation before execution.

                    - `type: :always_ask`

                      - `:always_ask`

              - `default_config: BetaManagedAgentsAgentToolsetDefaultConfig`

                Resolved default configuration for agent tools.

                - `enabled: bool`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy | BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `class BetaManagedAgentsAlwaysAllowPolicy`

                    Tool calls are automatically approved without user confirmation.

                  - `class BetaManagedAgentsAlwaysAskPolicy`

                    Tool calls require user confirmation before execution.

              - `type: :agent_toolset_20260401`

                - `:agent_toolset_20260401`

            - `class BetaManagedAgentsMCPToolset`

              - `configs: Array[BetaManagedAgentsMCPToolConfig]`

                - `enabled: bool`

                - `name: String`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy | BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `class BetaManagedAgentsAlwaysAllowPolicy`

                    Tool calls are automatically approved without user confirmation.

                  - `class BetaManagedAgentsAlwaysAskPolicy`

                    Tool calls require user confirmation before execution.

              - `default_config: BetaManagedAgentsMCPToolsetDefaultConfig`

                Resolved default configuration for all tools from an MCP server.

                - `enabled: bool`

                - `permission_policy: BetaManagedAgentsAlwaysAllowPolicy | BetaManagedAgentsAlwaysAskPolicy`

                  Permission policy for tool execution.

                  - `class BetaManagedAgentsAlwaysAllowPolicy`

                    Tool calls are automatically approved without user confirmation.

                  - `class BetaManagedAgentsAlwaysAskPolicy`

                    Tool calls require user confirmation before execution.

              - `mcp_server_name: String`

              - `type: :mcp_toolset`

                - `:mcp_toolset`

            - `class BetaManagedAgentsCustomTool`

              A custom tool as returned in API responses.

              - `description: String`

              - `input_schema: BetaManagedAgentsCustomToolInputSchema`

                JSON Schema for custom tool input parameters.

                - `type: :object`

                  - `:object`

                - `properties: Hash[Symbol, untyped]`

                - `required: Array[String]`

              - `name: String`

              - `type: :custom`

                - `:custom`

          - `type: :agent`

            - `:agent`

          - `version: Integer`

        - `type: :coordinator`

          - `:coordinator`

      - `name: String`

      - `skills: Array[BetaManagedAgentsAnthropicSkill | BetaManagedAgentsCustomSkill]`

        - `class BetaManagedAgentsAnthropicSkill`

          A resolved Anthropic-managed skill.

        - `class BetaManagedAgentsCustomSkill`

          A resolved user-created custom skill.

      - `system_: String`

      - `tools: Array[BetaManagedAgentsAgentToolset20260401 | BetaManagedAgentsMCPToolset | BetaManagedAgentsCustomTool]`

        - `class BetaManagedAgentsAgentToolset20260401`

        - `class BetaManagedAgentsMCPToolset`

        - `class BetaManagedAgentsCustomTool`

          A custom tool as returned in API responses.

      - `type: :agent`

        - `:agent`

      - `version: Integer`

    - `metadata: Hash[Symbol, String]`

      The session's full metadata bag after the update. Present when the update set non-empty metadata; absent when metadata was unchanged or cleared to empty.

    - `title: String`

      The session's new title. Present only when the update changed it.

  - `class BetaManagedAgentsSystemMessageEvent`

    A mid-conversation system message event. Carries system-role content that is appended to the session as a `role: "system"` turn.

    - `id: String`

      Unique identifier for this event.

    - `content: Array[BetaManagedAgentsSystemContentBlock]`

      System content blocks. Text-only.

      - `text: String`

        The text content.

      - `type: :text`

        - `:text`

    - `type: :"system.message"`

      - `:"system.message"`

    - `processed_at: Time`

      A timestamp in RFC 3339 format

### Example

```ruby
require "anthropic"

anthropic = Anthropic::Client.new(api_key: "my-anthropic-api-key")

beta_managed_agents_stream_session_thread_events = anthropic.beta.sessions.threads.events.stream(
  "sthr_011CZkZVWa6oIjw0rgXZpnBt",
  session_id: "sesn_011CZkZAtmR3yMPDzynEDxu7"
)

puts(beta_managed_agents_stream_session_thread_events)
```

#### Response

```json
{
  "id": "sevt_011CZkZGOp0iBcp4kaQSihUmy",
  "content": [
    {
      "text": "Where is my order #1234?",
      "type": "text"
    }
  ],
  "type": "user.message",
  "processed_at": "2026-03-15T10:00:00Z"
}
```
