Anthropic says these topics are too dangerous to let its Fable 5 model talk about

Anthropic has implemented safeguards on Fable 5 that restrict responses on cybersecurity, biology, and chemistry topics due to their advanced capabilities in these areas. When users ask about these sensitive topics, the model automatically defers to Claude Opus 4.8, an earlier, less powerful model. The safeguards have been tuned conservatively and trigger in less than 5% of sessions on average, though they may occasionally block harmless requests.

Source: Ars Technica | 2026-06-09