Pyyan / Compare / GPT-5.4 mini vs Claude Fable 5.1

GPT-5.4 mini vs Claude Fable 5.1

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Language Models · verified 2 Sept 2026

GPT-5.4 miniOpenAIcurrent
Claude Fable 5.1Anthropiccurrent
3 slots left
SpecificationGPT-5.4 miniClaude Fable 5.1
SummaryCheap tier for high-volume work.Same price as Fable 5, and cache reads cost a quarter of what they did.
Context—1M
Input ($/Mtok)$0.75$10
Output ($/Mtok)$4.5$50
LicenceProprietaryProprietary
Max output—128K
Parameters—Not published
Released—1 Sep 2026
Model ID—claude-fable-5-1
CategoryLanguage ModelsLanguage Models
OfficialOpenAI ↗—

Highlighted rows are where these differ.

GPT-5.4 mini

Cheap tier for high-volume work.

Best for high volume.

Full spec sheet →

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 →