Anthropic loosens Fable 5's biology restrictions but keeps the guardrails on for virology and toxicology

Anthropic has reduced false positives in Fable 5's biology safety filters by approximately 85%. Previously, nearly all biology-related queries were blocked and rerouted to the less capable Opus 5. The restrictions remain in place for sensitive dual-use topics such as virology and toxicology, ensuring these areas are still under strict oversight. This change reflects the company's efforts to enhance model performance while maintaining safety standards.