Anthropic has launched Claude Fable 5, the first publicly available version of its powerful Mythos model, accessible through its Claude API and Enterprise plans. The model excels at software engineering, knowledge work, and vision, but enforces hard safety limits, blocking responses in high-risk areas like cybersecurity, biology, and chemistry by deferring to Claude Opus 4.8. To guard against misuse, Anthropic is requiring a 30-day data retention policy on all traffic—even for enterprises with prior zero-retention agreements—which it says will be used solely to defend against novel attacks and jailbreaks.

Anthropic has released Claude Fable 5, a publicly accessible version of its advanced Mythos AI model, now available through its API and enterprise plans. The model excels in software engineering and knowledge work but has strict safety limits, blocking responses in high-risk areas like cybersecurity and biology. Anthropic conducted extensive testing to prevent jailbreaks and will retain user data for 30 days to monitor potential attacks.