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Pyyan / Compare / Kimi K3.1 Pro vs Claude Fable 5.1

Kimi K3.1 Pro vs Claude Fable 5.1

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Language Models · verified 26 Oct 2026

Kimi K3.1 ProMoonshot AIcurrent
Claude Fable 5.1Anthropiccurrent
3 slots left
SpecificationKimi K3.1 ProClaude Fable 5.1
SummaryFrontier coding numbers at a fifth of the price, with the weights promised for November.Same price as Fable 5, and cache reads cost a quarter of what they did.
Context1M1M
Input ($/Mtok)$2$10
Output ($/Mtok)$10$50
LicenceClosed for now, weights promised 4 Nov 2026Proprietary
Max output944K128K
Parameters3T class, exact count not publishedNot published
Released23 Oct 20261 Sep 2026
Model IDkimi-k3.1-proclaude-fable-5-1
CategoryLanguage ModelsLanguage Models
OfficialMoonshot AI ↗—

Highlighted rows are where these differ.

Kimi K3.1 Pro

  • 65.7% on Terminal-Bench 4.0 in Moonshot's own table, against 66.4% for Claude Opus 5.5 and 58.2% for GPT-6 Astra
  • Claim-level hallucination rate down from 23.4% on K3 to 8.3%
  • Cyber training data deliberately removed, which Moonshot says costs about nine points on xdev-bench-hard
  • Full weights promised by 4 November 2026, so the licence is not yet knowable

Best for long-horizon coding when the budget is the constraint.

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 →