Claude Fable 5.1 Hunts Bugs. In June That Got It Shut Off
Anthropic released Claude Fable 5.1 and Mythos 5.1 on September 1, 2026. The price stays at $10 and $50 per million tokens, cache reads drop 75%, and the model is now allowed to hunt software vulnerabilities, the same kind of task Anthropic says sat behind the jailbreak claim that got Fable 5 switched off in June.