Fable 5.2 beats Opus 5.5 on most evals, runs 30% faster, passes alignment tests
claudeai · x · 2026-11-10
Anthropic says Fable 5.2 and Mythos 5.2 outperform Opus 5.5 on nearly all evaluated capabilities and generate output up to 30% faster than the 5.1 versions, with clearer communication.
On alignment, the models performed as well as or better than recent models, with external pre-release evaluation by AISecurity Inst, Frontier Design, and METR. The attached chart compares scores across benchmarks including FrontierCode 2.0, Terminal-Bench-Science, OSWorld, and RoboDojo.
Related event: Anthropic Launches Claude Fable 5.2 and Mythos 5.2(45 posts)→
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