
Anthropic backs open weights—and mandatory testing for powerful models
Anthropic says it has never supported a categorical ban on open-weight models and calls models without dangerous capabilities a public good. Its proposed dividing line is capability: sufficiently powerful open and closed models should face mandatory pre-release testing for cyber, biological, and alignment risks, while less capable models such as those from startups and academia would be exempt. The position rejects blanket bans but also rejects the assumption that openness automatically favors defenders, because released weights cannot be withdrawn and safeguards can be removed.