Positioned a tier above the previous Opus models, Claude Fable 5 sets a new benchmark for generally available AI, outperforming rivals like OpenAI's GPT-5.5.

Anthropic has released a full version of its cybersecurity-centric Claude Mythos model—along with a safer version for the general public.

It says new safeguards make it possible to release a Mythos-class model it previously said was too risky to make public.