Claude Fable 5.1 Doubles Scores on Science Benchmarks

testingcatalog · x · 2026-09-02

Anthropic announced Claude Fable 5.1 and Claude Mythos 5.1. The model scores 52.6% on Terminal-Bench-Science 0.1, more than doubling Fable 5's performance. On Terminal-Bench 4.0, it achieves 55.8% compared to Fable 5's 42.0%. Features include plain language writing, spreadsheet creation with number verification, and clear source citation.

Related event: Anthropic Launches Claude Fable 5.1 and Mythos 5.1 with 75% Cache Price Cut(39 posts)→

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