Claude Fable 5.1

claude-fable-5-1 · Anthropic

Claude-fable-5-1 is Anthropic's most capable newly released model, suitable for the most demanding reasoning and long-running agent work. Claude Fable 5.1, while keeping input and output prices the same as Claude Fable 5, reduces cache read prices to one quarter of the original and is more capable for long-running agent programming, multi-step research, and document, spreadsheet, and slide processing. (The model is extremely expensive and not recommended for casual use.)

API Pricing

Input$11 / 1M tokens
Output$55 / 1M tokens
Cache read$0.275 / 1M tokens

Specifications

Context1M tokens
Max output128K tokens
Modalitiestext, image, PDF
CapabilitiesThinking, Streaming, Tool calling, Code interpreter, Computer use, Memory tool, Structured outputs, Citations, Prompt caching
Endpointschat_completions, claude_api

Frequently asked questions

What is Claude Fable 5.1?

Claude-fable-5-1 is Anthropic's most capable newly released model, suitable for the most demanding reasoning and long-running agent work. Claude Fable 5.1, while keeping input and output prices the same as Claude Fable 5, reduces cache read prices to one quarter of the original and is more capable for long-running agent programming, multi-step research, and document, spreadsheet, and slide processing. (The model is extremely expensive and not recommended for casual use.)

What is the context length of Claude Fable 5.1?

Claude Fable 5.1 has a 1,000,000 token context window. It supports up to 128,000 output tokens.

How much does Claude Fable 5.1 cost?

On AIHubMix, Claude Fable 5.1 costs $11 per million input tokens and $55 per million output tokens. Cached input reads are billed at $0.275 per million tokens.

What modalities does Claude Fable 5.1 support?

Claude Fable 5.1 accepts text, image and PDF input.

What capabilities does Claude Fable 5.1 support?

Claude Fable 5.1 supports thinking, tool calling, function calling and structured outputs. Per-protocol parameter support is listed in the capability table on this page.

How do I call Claude Fable 5.1 via API?

Claude Fable 5.1 is available through the AIHubMix unified API. The API is OpenAI-compatible: point your OpenAI SDK at https://aihubmix.com/v1, use your AIHubMix API key, and set the model name to claude-fable-5-1 — no other code changes needed.

Who created Claude Fable 5.1?

Claude Fable 5.1 is developed by Anthropic. AIHubMix aggregates it alongside models from other providers behind one API and one bill.

When was Claude Fable 5.1 released?

Claude Fable 5.1 was released on September 2, 2026 by Anthropic.

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Use Claude Fable 5.1 via the AIHubMix unified API — one interface for every major LLM.