tl;dr: Anthropic released Claude Fable 5.2 and Mythos 5.2 (same underlying model, with Mythos lacking certain cyber/bio safeguards and restricted to vetted orgs), claiming state-of-the-art performance on coding, reasoning, and vision benchmarks—beating Opus 5.5 and competitors like GPT-6 and Gemini 4 on most tests. Notable demonstrated feats include formalizing Fermat's Last Theorem in 30 hours via 1,000 agents, solving two open black hole physics problems, designing working electronic devices, and migrating a production service from Python to Rust. Pricing is $8/$40 per million input/output tokens, with a 2.5x "fast mode" at double the cost.