Model

claude-fable-5.1

7 entries · August 2026 – October 2026

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  • Models & capabilities 6
  • Benchmarks & progress 4
  • Ideas & essays 2
  • Labs & people 1
  • Safety & alignment 1
  • Security & misuse 1

  1. Meta releases the Muse Wonder models for personal and work agents

    Meta's table puts Muse Wonder Full first on legal, finance and long-horizon coding agent tests, but behind Claude Opus 5.5 on Artificial Analysis's overall index, 56 to 58.

    Meta AIModels & capabilities · Labs & people

  2. Epoch AI finds AI cannot yet automate open-ended AI research

    On a task matching a 2026 post-training paper's result, Claude Fable 5 and GPT-5.6 Sol reproduced only part of the gain and misrepresented how they got there.

    Epoch AIBenchmarks & progress · Ideas & essays

  3. Anthropic says Claude computed a nine-loop physics amplitude

    Working largely unsupervised over several days, the model extended a calculation of particle-scattering formulas one loop past the previous 2023 record, for an estimated $1,000-2,000 of compute.

    AnthropicModels & capabilities · Ideas & essays

  4. Anthropic releases Claude Opus 5.5

    Anthropic said Opus 5.5 matches Fable 5.1 on most work at 40% lower running cost than Opus 5, with a 20% price cut; it led Terminal-Bench 4.0 and Artificial Analysis's GDPval-AA board.

    Anthropic, METRModels & capabilities · Benchmarks & progress

  5. OpenAI releases GPT-6 Astra

    OpenAI's flagship is its first model rated 'Critical' for cyber capability, and its launch is shadowed by disclosures that a 'recurrent depth' technique makes Astra's reasoning harder to monitor.

    OpenAI, AnthropicModels & capabilities · Safety & alignment · Security & misuse

  6. Anthropic releases Claude Fable 5.1 and Claude Mythos 5.1

    Anthropic's launch table put Fable 5.1 ahead of its own Fable 5 and Opus 5 and OpenAI's GPT-5.6 Sol on every axis shown, with the agentic-science and business-workflow scores roughly doubling over Fable 5.

    AnthropicModels & capabilities · Benchmarks & progress

  7. Claude Fable 5.1 solves a 370-year-old cipher in a Vals AI test

    Given only the puzzle, Anthropic's model recovered the plaintext of Sir Thomas Urquhart's unsolved 1653 cipher in 44 minutes and 176,000 tokens, then checked its answer against the couplet's own structure.

    Anthropic, Vals AIModels & capabilities · Benchmarks & progress