# Completions

## Create a Text Completion

**post** `/v1/complete`

[Legacy] Create a Text Completion.

The Text Completions API is a legacy API. We recommend using the [Messages API](https://docs.claude.com/en/api/messages) going forward.

Future models and features will not be compatible with Text Completions. See our [migration guide](https://docs.claude.com/en/api/migrating-from-text-completions-to-messages) for guidance in migrating from Text Completions to Messages.

### Header Parameters

- `"anthropic-beta": optional array of AnthropicBeta`

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

  - `string`

  - `"message-batches-2024-09-24" or "prompt-caching-2024-07-31" or "computer-use-2024-10-22" or 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"`

### Body Parameters

- `max_tokens_to_sample: number`

  The maximum number of tokens to generate before stopping.

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

- `model: Model`

  The model that will complete your prompt.

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

  - `"claude-fable-5" or "claude-mythos-5" or "claude-opus-4-8" or 17 more`

    The model that will complete your prompt.

    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-mythos-5"`

      Most capable model for cybersecurity and biology research

    - `"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-mythos-preview"`

      New class of intelligence, strongest in coding and cybersecurity

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

      Frontier intelligence for long-running 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

    - `"claude-opus-4-1"`

      Exceptional model for specialized complex tasks

    - `"claude-opus-4-1-20250805"`

      Exceptional model for specialized complex tasks

    - `"claude-opus-4-0"`

      Powerful model for complex tasks

    - `"claude-opus-4-20250514"`

      Powerful model for complex tasks

    - `"claude-sonnet-4-0"`

      High-performance model with extended thinking

    - `"claude-sonnet-4-20250514"`

      High-performance model with extended thinking

    - `"claude-3-haiku-20240307"`

      Fast and cost-effective model

  - `string`

- `prompt: string`

  The prompt that you want Claude to complete.

  For proper response generation you will need to format your prompt using alternating `

  Human:`and`

  Assistant:` conversational turns. For example:

  ```
  "
  
  Human: {userQuestion}
  
  Assistant:"
  ```

  See [prompt validation](https://docs.claude.com/en/api/prompt-validation) and our guide to [prompt design](https://docs.claude.com/en/docs/intro-to-prompting) for more details.

- `metadata: optional Metadata`

  An object describing metadata about the request.

  - `user_id: optional string`

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

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

- `stop_sequences: optional array of string`

  Sequences that will cause the model to stop generating.

  Our models stop on `"

  Human:"`, and may include additional built-in stop sequences in the future. By providing the stop_sequences parameter, you may include additional strings that will cause the model to stop generating.

- `stream: optional boolean`

  Whether to incrementally stream the response using server-sent events.

  See [streaming](https://docs.claude.com/en/api/streaming) for details.

- `temperature: optional number`

  Amount of randomness injected into the response.

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

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

- `top_k: optional number`

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

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

  Recommended for advanced use cases only.

- `top_p: optional number`

  Use nucleus sampling.

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

  Recommended for advanced use cases only.

### Returns

- `Completion object { id, completion, model, 2 more }`

  - `id: string`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `completion: string`

    The resulting completion up to and excluding the stop sequences.

  - `model: Model`

    The model that will complete your prompt.

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

    - `"claude-fable-5" or "claude-mythos-5" or "claude-opus-4-8" or 17 more`

      The model that will complete your prompt.

      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-mythos-5"`

        Most capable model for cybersecurity and biology research

      - `"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-mythos-preview"`

        New class of intelligence, strongest in coding and cybersecurity

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

        Frontier intelligence for long-running 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

      - `"claude-opus-4-1"`

        Exceptional model for specialized complex tasks

      - `"claude-opus-4-1-20250805"`

        Exceptional model for specialized complex tasks

      - `"claude-opus-4-0"`

        Powerful model for complex tasks

      - `"claude-opus-4-20250514"`

        Powerful model for complex tasks

      - `"claude-sonnet-4-0"`

        High-performance model with extended thinking

      - `"claude-sonnet-4-20250514"`

        High-performance model with extended thinking

      - `"claude-3-haiku-20240307"`

        Fast and cost-effective model

    - `string`

  - `stop_reason: string`

    The reason that we stopped.

    This may be one the following values:

    * `"stop_sequence"`: we reached a stop sequence — either provided by you via the `stop_sequences` parameter, or a stop sequence built into the model
    * `"max_tokens"`: we exceeded `max_tokens_to_sample` or the model's maximum

  - `type: "completion"`

    Object type.

    For Text Completions, this is always `"completion"`.

    - `"completion"`

### Example

```http
curl https://api.anthropic.com/v1/complete \
    -H 'Content-Type: application/json' \
    -H 'anthropic-version: 2023-06-01' \
    -H "X-Api-Key: $ANTHROPIC_API_KEY" \
    --max-time 600 \
    -d '{
          "max_tokens_to_sample": 256,
          "model": "claude-2.1",
          "prompt": "\\n\\nHuman: Hello, world!\\n\\nAssistant:",
          "temperature": 1,
          "top_k": 5,
          "top_p": 0.7
        }'
```

#### Response

```json
{
  "id": "compl_018CKm6gsux7P8yMcwZbeCPw",
  "completion": " Hello! My name is Claude.",
  "model": "claude-2.1",
  "stop_reason": "stop_sequence",
  "type": "completion"
}
```

## Domain Types

### Completion

- `Completion object { id, completion, model, 2 more }`

  - `id: string`

    Unique object identifier.

    The format and length of IDs may change over time.

  - `completion: string`

    The resulting completion up to and excluding the stop sequences.

  - `model: Model`

    The model that will complete your prompt.

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

    - `"claude-fable-5" or "claude-mythos-5" or "claude-opus-4-8" or 17 more`

      The model that will complete your prompt.

      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-mythos-5"`

        Most capable model for cybersecurity and biology research

      - `"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-mythos-preview"`

        New class of intelligence, strongest in coding and cybersecurity

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

        Frontier intelligence for long-running 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

      - `"claude-opus-4-1"`

        Exceptional model for specialized complex tasks

      - `"claude-opus-4-1-20250805"`

        Exceptional model for specialized complex tasks

      - `"claude-opus-4-0"`

        Powerful model for complex tasks

      - `"claude-opus-4-20250514"`

        Powerful model for complex tasks

      - `"claude-sonnet-4-0"`

        High-performance model with extended thinking

      - `"claude-sonnet-4-20250514"`

        High-performance model with extended thinking

      - `"claude-3-haiku-20240307"`

        Fast and cost-effective model

    - `string`

  - `stop_reason: string`

    The reason that we stopped.

    This may be one the following values:

    * `"stop_sequence"`: we reached a stop sequence — either provided by you via the `stop_sequences` parameter, or a stop sequence built into the model
    * `"max_tokens"`: we exceeded `max_tokens_to_sample` or the model's maximum

  - `type: "completion"`

    Object type.

    For Text Completions, this is always `"completion"`.

    - `"completion"`
