Policy

Anthropic says it blocked AI queries that could have aided bioweapons work

Anthropic said it disrupted attempts to use Claude for work that could support biological weapons, including a request for help drafting a gain-of-function grant proposal involving chikungunya virus, in a threat report covering December 2025 through August 2026.

Anthropic's report covers seven areas of misuse: cyber operations, influence operations, surveillance, scams and fraud, biological misuse, conventional weapons and illicit distillation. CNN reported that the company flagged about 35 distinct research efforts over a 30-day period and published five biological case studies, including work on gain-of-function research, bird flu and novel toxins, while acknowledging it could not always determine whether users intended harm. Affiliated institutions and countries were not identified.

The Associated Press reported that the chikungunya request sought help with a grant application for research to make the virus more transmissible and better at evading immunity, that Anthropic banned linked accounts, and that it shared findings with authorities and other AI companies. Anthropic said newer models, including Claude Fable 5, restrict a broader range of dual-use biological queries. The account of what was blocked comes from Anthropic's own investigation. John Thickstun, a Cornell computer scientist, told AP that such firms are making societal value judgments without democratic oversight.

Source details
Source
Anthropic

Source reporting

Read the original reporting and research behind this briefing.