Pyyan / Compare / Claude Fable 5.1 vs GPT-6 Astra

Claude Fable 5.1 vs GPT-6 Astra

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Language Models · verified 5 Sept 2026

Claude Fable 5.1Anthropiccurrent
GPT-6 AstraOpenAIcurrent
3 slots left
SpecificationClaude Fable 5.1GPT-6 Astra
SummarySame price as Fable 5, and cache reads cost a quarter of what they did.Saturates three of the benchmarks it reports, and ships disabled for enterprise.
Context1M1.05M
Input ($/Mtok)$10$10
Output ($/Mtok)$50$50
LicenceProprietaryProprietary
Max output128K128K
ParametersNot publishedNot published
Released1 Sep 20263 Sep 2026
Model IDclaude-fable-5-1gpt-6-astra
CategoryLanguage ModelsLanguage Models
Official

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 →

GPT-6 Astra

  • 97.6% on FrontierMath Tier 4, 99.9% on ARC-AGI-3 and 100% on ExploitBench
  • Above 272K input tokens the whole request reprices: input and cache at 2x, output at 1.5x
  • Rolls out to OpenAI's Daybreak cyber programme first, and arrives switched off for enterprise

Best for hard reasoning and computer use.

Full spec sheet →