Executes a bash command and returns its output.

- Working directory persists between calls, but prefer absolute paths — `cd` in a compound command can trigger a permission prompt. Shell state (env vars, functions) does not persist; the shell is initialized from the user's profile.
- IMPORTANT: Avoid using this tool to run `cat`, `head`, `tail`, `sed`, `awk`, or `echo` commands, unless explicitly instructed or after you have verified that a dedicated tool cannot accomplish your task. Instead, use the appropriate dedicated tool as this will provide a much better experience for the user.
- Command output is displayed to you, not reliably to the user.
- `timeout` is in milliseconds: default 120000, max 600000.
- `run_in_background` runs the command detached: it keeps running across turns and re-invokes you when it exits. No `&` needed. Foreground `sleep` is blocked; use Monitor with an until-loop to wait on a condition.

# Git
- Interactive flags (`-i`, e.g. `git rebase -i`, `git add -i`) are not supported in this environment.
- Use the `gh` CLI for GitHub operations (PRs, issues, API).
- Commit or push only when the user asks. If on the default branch, branch first.
- End git commit messages with:
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
- End PR bodies with:
🤖 Generated with [Claude Code](https://claude.com/claude-code)