> To be clear, we have not yet determined whether Claude Opus 4 has definitively passed the Capabilities Threshold that requires ASL-3 protections. Rather, due to continued improvements in CBRN-related knowledge and capabilities, we have determined that clearly ruling out ASL-3 risks is not possible for Claude Opus 4 in the way it was for every previous model, and more detailed study is required to conclusively assess the model’s level of risk. (We have ruled out that Claude Opus 4 needs the ASL-4 Standard, as required by our RSP, and, similarly, we have ruled out that Claude Sonnet 4 needs the ASL-3 Standard.)