> ## Documentation Index
> Fetch the complete documentation index at: https://veniceai-feat-models-redesign.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Claude Fable 5.1 API

> Claude Fable 5.1 API on Venice: 1M context, $12.00 input and $60.00 output per 1M tokens. Anonymized access without your identity.

export const HubMount = ({view, children, ...props}) => {
  const [hub, setHub] = useState(null);
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        return res.json();
      }).catch(err => i + 1 < urls.length ? load(i + 1) : Promise.reject(err));
      const Frag = <></>.type;
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<HubMount view="ModelPage" data={{"family":{"slug":"claude-fable-5-1","name":"Claude Fable 5.1","modality":"text","task":"chat","provider":"anthropic","description":"Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work such as long code refactors, front-end development, and finance and analysis tasks. It features a 1M token context window, 128K max output tokens, always-on adaptive thinking, and strong multimodal capabilities, and tends to be more concise in its plans and summaries.","primary":"claude-fable-5-1","variants":["claude-fable-5-1"],"created":1787961600,"updated":1787961600,"privacy":["anonymized"],"sets":["venice_recommendations"]},"models":[{"id":"claude-fable-5-1","name":"Claude Fable 5.1","type":"text","modality":"text","task":"chat","variant":"standard","provider":"anthropic","created":1787961600,"description":"Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work such as long code refactors, front-end development, and finance and analysis tasks. It features a 1M token context window, 128K max output tokens, always-on adaptive thinking, and strong multimodal capabilities, and tends to be more concise in its plans and summaries.","privacy":"anonymized","sets":["venice_recommendations"],"text":{"context":1000000,"maxOutput":128000,"reasoning":{"supported":true,"effort":["low","medium","high","xhigh","max"],"defaultEffort":"high"},"caps":{"tools":true,"structured":true,"vision":true,"maxImages":10,"webSearch":true,"code":true}},"pricing":{"input":12,"output":60,"cacheRead":0.3,"cacheWrite":15,"blended":24},"headline":{"value":24,"unit":"per 1M tokens","basis":"blended"},"endpoints":[{"id":"chat","method":"POST","path":"/chat/completions","name":"Chat Completions","status":"stable","recommended":true},{"id":"responses","method":"POST","path":"/responses","name":"Responses","status":"alpha"}],"family":"claude-fable-5-1"}],"related":{"similar":[{"slug":"gpt-6-astra-pro","name":"GPT-6 Astra Pro","provider":"openai","modality":"text","privacy":["anonymized"],"created":1788566400,"headline":{"value":25,"unit":"per 1M tokens","basis":"blended"},"variants":1},{"slug":"gpt-6-astra","name":"GPT-6 Astra","provider":"openai","modality":"text","privacy":["anonymized"],"created":1788566400,"headline":{"value":20,"unit":"per 1M tokens","basis":"blended"},"variants":1},{"slug":"claude-fable-5","name":"Claude Fable 5","provider":"anthropic","modality":"text","privacy":["anonymized"],"created":1781049600,"headline":{"value":24,"unit":"per 1M tokens","basis":"blended"},"variants":1},{"slug":"gpt-5-5","name":"GPT-5.5","provider":"openai","modality":"text","privacy":["anonymized"],"created":1776902400,"headline":{"value":14.0625,"unit":"per 1M tokens","basis":"blended"},"variants":1}],"versions":[{"slug":"claude-fable-5","name":"Claude Fable 5","provider":"anthropic","modality":"text","privacy":["anonymized"],"created":1781049600,"headline":{"value":24,"unit":"per 1M tokens","basis":"blended"},"variants":1}]},"providers":{"anthropic":{"slug":"anthropic","name":"Anthropic","logo":"/images/icons/models/opus.svg"},"openai":{"slug":"openai","name":"OpenAI","logo":"/images/icons/models/openai.svg"}},"faq":[{"q":"How much does the Claude Fable 5.1 API cost?","a":"$12.00 per 1M input tokens and $60.00 per 1M output tokens, with cached input at $0.30 per 1M. Prices are in USD and can be paid in DIEM at parity."},{"q":"What is the Claude Fable 5.1 model ID?","a":"Use `claude-fable-5-1` as the `model` parameter."},{"q":"Is the Claude Fable 5.1 API private?","a":"Claude Fable 5.1 is anonymized: Venice forwards requests to the provider without your identity, but the provider may retain prompt data, so use a private model for sensitive work."},{"q":"What is the context window of Claude Fable 5.1?","a":"1M tokens of context, with up to 125K output tokens per response."},{"q":"What does Claude Fable 5.1 support?","a":"Claude Fable 5.1 supports function calling, structured outputs, reasoning, image input, web search and prompt caching. Reasoning effort is adjustable with `reasoning_effort`: low, medium, high, xhigh and max (default high)."},{"q":"Which endpoint does the Claude Fable 5.1 API use?","a":"Call `POST /chat/completions`. `/responses` (Alpha) is also supported."}]}} />

<div className="vx-static">
  <Accordion title="Plain-text specification">
    # Claude Fable 5.1 API

    Claude Fable 5.1 is a large language model by Anthropic, available on the Venice API as `claude-fable-5-1`. Requests are anonymized, so the provider never sees your identity.

    Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work such as long code refactors, front-end development, and finance and analysis tasks. It features a 1M token context window, 128K max output tokens, always-on adaptive thinking, and strong multimodal capabilities, and tends to be more concise in its plans and summaries.

    ## Claude Fable 5.1 API pricing

    | Model ID | Variant | Privacy | Price |
    | - | - | - | - |
    | `claude-fable-5-1` | Standard | Anonymized | $12.00 input / $60.00 output per 1M tokens |

    ## Claude Fable 5.1 specifications

    | Spec | Value |
    | - | - |
    | Provider | Anthropic |
    | Released | Aug 29, 2026 |
    | Privacy | Anonymized |
    | Context window | 1M tokens |
    | Max output | 125K tokens |
    | Reasoning effort | low, medium, high, xhigh, max |

    ## How to use the Claude Fable 5.1 API

    Send requests to `POST https://api.venice.ai/api/v1/chat/completions` with `"model": "claude-fable-5-1"` and your API key.

    ```bash theme={null}
    curl https://api.venice.ai/api/v1/chat/completions \
      -H "Authorization: Bearer $VENICE_API_KEY" \
      -H "Content-Type: application/json" \
      -d '{
        "model": "claude-fable-5-1",
        "messages": [{ "role": "user", "content": "Explain TEE attestation in two sentences." }],
        "reasoning_effort": "high"
      }'
    ```

    ## Claude Fable 5.1 API FAQ

    ### How much does the Claude Fable 5.1 API cost?

    $12.00 per 1M input tokens and $60.00 per 1M output tokens, with cached input at \$0.30 per 1M. Prices are in USD and can be paid in DIEM at parity.

    ### What is the Claude Fable 5.1 model ID?

    Use `claude-fable-5-1` as the `model` parameter.

    ### Is the Claude Fable 5.1 API private?

    Claude Fable 5.1 is anonymized: Venice forwards requests to the provider without your identity, but the provider may retain prompt data, so use a private model for sensitive work.

    ### What is the context window of Claude Fable 5.1?

    1M tokens of context, with up to 125K output tokens per response.

    ### What does Claude Fable 5.1 support?

    Claude Fable 5.1 supports function calling, structured outputs, reasoning, image input, web search and prompt caching. Reasoning effort is adjustable with `reasoning_effort`: low, medium, high, xhigh and max (default high).

    ### Which endpoint does the Claude Fable 5.1 API use?

    Call `POST /chat/completions`. `/responses` (Alpha) is also supported.

    ## Related models

    * [Claude Fable 5 API](/models/claude-fable-5): $12.00 input / $60.00 output per 1M tokens
    * [GPT-6 Astra Pro API](/models/gpt-6-astra-pro): $12.50 input / $62.50 output per 1M tokens
    * [GPT-6 Astra API](/models/gpt-6-astra): $10.00 input / $50.00 output per 1M tokens
    * [GPT-5.5 API](/models/gpt-5-5): $6.25 input / $37.50 output per 1M tokens
  </Accordion>
</div>


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