Anthropic loosens Fable 5's biology safeguards, cutting false-positive fallbacks by 85%
On Aug 7, Anthropic said it rewrote Fable 5's biology-safety classifiers with expert review to cut false-positive "fallbacks" — cases where a benign question gets rerouted to the less-capable Opus 5 model — by about 85% overall, testing found. Anthropic expects the steepest drops on claude.ai (67%) and Cowork (55%), with smaller gains on Claude Code (17%) and the Claude Platform (7%). The model still blocks dual-use queries touching virology, toxicology, and molecular design pending "trusted access pathways," but clinicians, students, and researchers should see far fewer benign questions get punted. It's been the most substantive Anthropic news in days — Aug 8 brought two Claude Code releases (one substantial, one routine) and Aug 9 has been quiet so far.