Claude Fable 5.1

Maker

Anthropic

Released

1 Sep 2026

Open weights

No, you use it through the maker's app or paid API

License

Owned by the maker, not open

Memory (context window)

1 million tokens (how much it can read at once)1,000,000 tokens exactly

Price

$10 for every million tokens you send, $50 for every million tokens it writesA token is a small piece of a word · checked 17 Oct 2026 · price source

Official page

Official page for Claude Fable 5.1 (anthropic.com)

• All-roundArtificial Analysis Intelligence Index

  53 index points Tied #2 of 17 models scored independent

  One combined score from many independent tests of how smart a model is.

  setting: max with fallback · as of 17 Oct 2026 · source

• Chat & writingLMArena Text

  1502 Arena score #3 of 15 models scored independent

  When real people compare two AI answers side by side without knowing which AI wrote them, which one do they pick more often?

  setting: Max · as of 15 Oct 2026 · source

• Build websites & appsLMArena WebDev

  1741 Arena score #3 of 18 models scored independent

  When people ask two AIs to build the same website or app and compare the results, which one do they pick?

  setting: Max · as of 17 Oct 2026 · source

• CodingLiveBench 2.0 Coding

  97.7 score out of 100 #1 of 15 models scored independent

  Fresh coding tasks with tests that check the answer, changed often so models cannot memorize them.

  setting: highest supported effort · as of 14 Oct 2026 · source

• ReasoningLiveBench 2.0 Reasoning

  91.7 score out of 100 #4 of 15 models scored independent

  Fresh logic and puzzle questions with one right answer, changed often so models cannot memorize them.

  setting: highest supported effort · as of 14 Oct 2026 · source

• Hardest examHumanity's Last Exam (no tools)

  60.9% #2 of 6 models scored maker's own number

  2,500 expert questions written to be too hard for AI, answered without web search or code.

  as of 22 Sep 2026 · source

• New puzzlesARC-AGI-2

  90.0% #4 of 11 models scored independent

  New picture puzzles a model has never seen, so it has to reason instead of remember. Harder for AI than for people.

  setting: Max, $4.49 per task · as of 18 Oct 2026 · source

• Agent tasksTerminal-Bench 4.0

  57.9 % of tasks done #3 of 6 models scored independent

  Can an AI agent finish real jobs in a computer's command line, like setting up software or fixing a broken project?

  setting: max, Claude Code · as of 18 Oct 2026 · source

• SpeedOutput speed

  71 tokens per second #11 of 16 models scored independent

  How many tokens (pieces of words) per second the model writes once it starts answering. Higher is faster.

  setting: max with fallback · as of 17 Oct 2026 · source

• GoogleGemini 4 Argon53 index pointsTied #2 of 17 models scored
• OpenAIGPT-6 Astra53 index pointsTied #2 of 17 models scored
• AnthropicClaude Opus 5.558 index points#1 of 17 models scored

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