Anthropic Reduces Biology False Positives for Fable 5 by 85%, Keeps Virology Guardrails

The Decoder · rss · 2026-08-08

Anthropic has significantly loosened the biology safety filters for its Fable 5 model, reducing false positives by approximately 85%.

Previously, nearly all biology-related queries were blocked and rerouted to the less capable Opus 5 model. While general biology restrictions have been eased, strict safety guardrails remain fully active for sensitive dual-use topics such as virology and toxicology.

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