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Pyyan / Compare / Claude Fable 5.1 vs Claude Fable 5

Claude Fable 5.1 vs Claude Fable 5

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Language Models · verified 2 Sept 2026

Claude Fable 5.1Anthropiccurrent
Claude Fable 5Anthropiccurrent
3 slots left
SpecificationClaude Fable 5.1Claude Fable 5
SummarySame price as Fable 5, and cache reads cost a quarter of what they did.Most capable widely released model, for the hardest reasoning and long-horizon agentic work.
Context1M1M
Input ($/Mtok)$10$10
Output ($/Mtok)$50$50
LicenceProprietaryProprietary
Max output128K128K
ParametersNot published—
Released1 Sep 2026—
Model IDclaude-fable-5-1claude-fable-5
CategoryLanguage ModelsLanguage Models
Official—Anthropic ↗

Highlighted rows are where these differ.

Claude Fable 5.1

  • Matches or beats Fable 5 at low and medium effort, and pulls clear at high effort
  • Cache reads cut to 25% of the old price, so re-reading a long context got much cheaper
  • Identical model to Mythos 5.1 underneath; the difference is the safeguards

Best for coding and long-running work.

Full spec sheet →

Claude Fable 5

  • Thinking is always on — the `thinking` param is rejected
  • Raw chain of thought is never returned
  • Requires 30-day data retention; unavailable under ZDR

Best for the hardest problems.

Full spec sheet →