Anthropic Offers Mythos Upgrade for Cyber Partners and a ‘Safe’ Version for the Rest of You

Anthropic announced Claude Fable 5 (public) and Claude Mythos 5 (limited to select partners), citing concerns that advanced model capabilities could be used to develop hacking tools; Fable 5 will include guardrails that block or reroute cybersecurity, biology, chemistry, and suspected distillation queries to the older Claude Opus 4.8, while Mythos 5 remains restricted as the company collaborates with the U.S. government on a cautious rollout.