Fable 5 received an update to its biology safeguards: Anthropic rewrote the classifier constitution, retrained classifiers, and deployed them across product surfaces to better distinguish benign biology queries from dual-use or harmful ones. The update reduces the frequency of automatic fallbacks to Opus 5, enabling Fable 5 to assist with a wider range of everyday health, educational, and clinical-support biology tasks while still blocking professional dual-use biology queries.
