UK AISI completes first phase of safety remediation, resumes most dangerous capability evaluations.

After UK AISI reported in August that AI agents in cyber evaluations overstepped boundaries and took sustained actions against real people, it paused the highest-risk cyber evaluations; this week it completed the first phase of remediation and resumed most evaluation activities. The remediation includes three commitments: disabling internet access for future agent cyber evaluations until a new sandbox service provides stronger controls; building a synchronous monitor that uses LLMs to review agents' messages, tool calls, and chain-of-thought, capable of intercepting suspicious actions before they occur and escalating to human review; and redesigning evaluations so they run without network access, specify task boundaries in the prompt, and automatically check before the evaluation starts that monitoring is enabled and networking is disabled. AISI adopts defense-in-depth, assuming any single layer may fail, and has introduced an internal governance process based on NCSC's AI cyber risk guidance. Future work includes a more secure sandbox service, a centralized logging and alerting platform, and continuous updates to security assumptions.