Anthropic ships Claude Fable 5.2 and Mythos 5.2: 30% faster, cheaper, formalized Fermat's Last Theorem in 30 hours
dl_weekly · x · 2026-11-14
Anthropic released Claude Fable 5.2 and Claude Mythos 5.2 (same underlying model), with gains in coding, reasoning, vision, science, and cybersecurity. Outputs are up to 30% faster than the 5.1 generation, priced at $8/M input and $40/M output tokens, with an optional fast mode (2.5x speed) at $16/$80 per million tokens.
Prerelease highlights
- Enabled otherwise-infeasible software migrations
- Designed three working electronic devices from scratch
- Solved two open problems in black hole physics
- Formalized Fermat's Last Theorem in 30 hours
Safety and access
- Fable 5.2 ships with strong cybersecurity and biology safeguards, available to all users
- Mythos access via the expanded Life Sciences and Cyber Verification Programs
- Novel evaluations targeting concerning behaviors like sandbox escapes
Related event: Anthropic releases Claude Fable 5.2 and Mythos 5.2(2 posts)→
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