Anthropic has updated Fable 5's biology safeguards to reduce unnecessary restrictions while maintaining protections against potentially harmful biological applications.
The company says improved safety classifiers reduced biology-related fallbacks by about 85%, allowing Fable 5 to handle more everyday health questions, educational biology requests, and clinical tasks. Anthropic retrained its classifier using revised rules, new training data, and feedback from internal and external experts to distinguish benign requests from harmful or dual-use research more accurately.
Fable 5 will continue routing sensitive areas, including virology, toxicology, molecular design, and professional drug development, to Opus 5 while Anthropic develops trusted access pathways.
