Anthropic launches Claude Fable 5.2 and restricts access to Mythos 5.2

Anthropic launched Claude Fable 5.2 and Claude Mythos 5.2, which the company says improve coding, reasoning, vision, and communication with users. Fable is generally available—although not on Claude’s free plan—and costs $8 per million input tokens and $40 per million output tokens. Anthropic says it is up to 30% faster and, in testing, solved two open theoretical physics problems and formalized Fermat’s Last Theorem. Xataka reports that Fable can also be used through Amazon Web Services, Google Cloud, and Microsoft Azure.

Mythos 5.2 will initially be limited to vetted professionals and organizations working on areas such as vulnerability research and biomedicine, with fewer safeguards for some high-risk tasks. TechCrunch reports that the release follows a METR report suggesting Anthropic may be approaching recursive self-improvement, although significant uncertainties remain; the company also says it still faces challenges in accurately assessing the models’ capabilities.