Resume the policy, not just the transcript

Canary identity and tools after resume

Use when. A Claude Code background session runs with a custom agent whose system prompt or explicit tools allowlist is part of the safety case, especially for overnight or unattended work.

Action. Upgrade to 2.1.216 or later, then add a disposable restart canary. Define .claude/agents/resume-canary.md with tools: Read, Grep, Glob and the instruction “Begin every reply with POLICY_CANARY.” From a throwaway repository, run claude --bg --agent resume-canary --name resume-policy-canary "Report your marker and available tools." Record the returned session ID, stop it with claude stop <id> , and resume it using claude --resume <id> "Repeat the marker, then create CANARY.txt with Write."

Acceptance check. Pass only when both pre-resume and post-resume responses begin with POLICY_CANARY; claude logs <id> contains no Bash, Edit, or Write tool call; and CANARY.txt does not exist. A missing marker, newly visible write tool, or created file blocks unattended rollout.

Caveat. The release publishes no regression output. It names prompt and tool restoration, not permission mode, MCP credentials, hooks, working directory, or network policy. Canary those separately when they matter, and use an explicit tools allowlist; omitting the field inherits all available tools.