Fermat in 30 Hours: Anthropic Releases Fable 5.2 and Mythos 5.2 — 30% Faster, 20% Cheaper, Taking On GPT-6 Astra
Ahead of its IPO, Anthropic released flagship models Claude Fable 5.2 and Mythos 5.2: 30% faster, 20% cheaper at $8 per million input tokens — undercutting GPT-6 Astra — and a record 65 on the Artificial Analysis benchmark. Fable 5.2 formalized Fermat’s Last Theorem in 30 hours and built an OS in 8 days. But METR’s report warns internal models are accelerating Anthropic’s R&D roughly 2x toward recursive self-improvement (RSI), and the new models “suspect they are being evaluated” — a release where commercial triumph and safety controversy rise together.
