
Anthropic cuts Fable 5 biology false positives by 85 percent while maintaining dual-use guardrails
Anthropic has substantially improved Fable 5's usability by reducing false-positive biology query blocks from near-total rejection to just 15 percent. The shift reflects a maturing approach to capability-safety tradeoffs: general biology queries now route to the full model rather than degrading to Opus 5, while dual-use risks in virology and toxicology remain gated. This calibration matters because it signals how frontier labs are operationalizing nuanced risk assessment rather than blanket restrictions, setting a precedent for balancing research utility against misuse potential.73











