From $10 usage-based🇺🇸
OpenAI's most capable model for hard end-to-end work, with five reasoning levels and a context of about one million tokens.
Claude Fable 5.1 AI features and pricing (October 2026)
Anthropic's model for demanding reasoning and long-horizon agentic work, with thinking always on.
Usage-based
from $10 usage-based
Pricing details
$10 per million input tokens and $50 per million output tokens. Batch is 50 percent cheaper; cache reads cost 2.5 percent of the input price.
What is Claude Fable 5.1?
Claude Fable 5.1 is Anthropic's model for demanding reasoning and long-horizon agentic work, recommended when evaluations on Claude Opus at higher effort still fall short.
Fable 5.1 accepts text and images and outputs text, with a context window of one million tokens and up to 128,000 output tokens. Thinking is adaptive and always on, with high as the default effort, which makes it slower than the rest of Anthropic's lineup. Its reliable knowledge cutoff is June 2026. It is offered on the Claude API, Amazon Bedrock, Google Cloud, Microsoft Foundry and Claude Platform on AWS, with retirement not before September 1, 2027.
Claude Fable 5.1 AI features and use cases
- Works through hard reasoning problemsThe model spends more thinking on each request by default. Teams use it for questions where step-by-step analysis matters more than speed.
- Carries long agent runsFable 5.1 is positioned for long-horizon agentic work with tools. Engineering and research teams run tasks that span many steps without close supervision.
- Serves as an escalation modelApplications can send most traffic to faster models and route only difficult cases to Fable. Cost stays controlled while hard cases get more capability.
What sets Claude Fable 5.1 apart
- Default effort is high and thinking cannot be switched off, so it trades speed for depth.
- Priced at 2.5 times Claude Opus 5.5 per token.
Where Claude Fable 5.1 is strongest
United States Available internationally
Anthropic PBC is registered in San Francisco.
Questions to ask before you buy Claude Fable 5.1
Billing is per token, with batch requests at half price and cached prompts much cheaper. On the Claude API, workspace data is stored in the US; inference can be pinned to the US for 1.1 times the price, while the global default may run anywhere. Amazon Bedrock and Google Cloud offer their own regional endpoints. In the US, check Colorado and Illinois rules if outputs feed decisions about people.
Claude Fable 5.1 reviews
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Questions about Claude Fable 5.1
When should I choose Fable over Opus?
Anthropic recommends starting with Claude Opus for most workloads and using Fable 5.1 for demanding reasoning and long-horizon agentic work, or when Opus at higher effort does not meet your evaluation targets.
What does Claude Fable 5.1 cost?
$10 per million input tokens and $50 per million output tokens, with batch requests at half price.
Is Fable slower than other Claude models?
Yes. Anthropic rates its latency as slower than Opus 5.5, Sonnet 5 and Haiku 4.5.
Claude Fable 5.1 update historyno updates yet
No changes recorded for Claude Fable 5.1 yet.
Changes the vendor made and confirmed user reports, each checked against the vendor's own pages. We review every tool monthly.
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