Anthropic launches Claude Fable 5, public version of Mythos model
Original: Anthropic’s Claude Fable 5 is a version of Mythos the public can access today
Why This Matters
First public release of advanced AI model with mandatory safety measures sets industry precedent
Anthropic released Claude Fable 5, the first publicly available version of its advanced Mythos AI model. The model excels at software engineering and vision tasks but includes safety guardrails that block high-risk responses in cybersecurity and biology areas.
Anthropic launched Claude Fable 5 on Tuesday, making its most powerful AI model available to the general public for the first time with safety limitations. The model is based on Mythos technology, previously limited to select partners due to cybersecurity concerns. Fable 5 excels at software engineering, knowledge work, and vision tasks but automatically blocks responses in high-risk areas like cybersecurity, biology, chemistry, and distillation, falling back to Claude Opus 4.8 instead. The company stress-tested the model with over 1,000 hours of jailbreak attempts and external red-teaming. Access is available through Claude API and Enterprise plans, with free inclusion in Pro, Max, Team plans until June 22, after which usage credits will be required. Anthropic also requires 30-day data retention for traffic monitoring, even for enterprises with previous zero-retention agreements, to defend against novel attacks.