[BUG] Git commit with heredoc always fails on first attempt when sandbox is enabled - system prompt fights itself

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

Claude Code's built-in system prompt instructs using heredoc for git commit, but heredoc requires creating temp files in /tmp, which is blocked by Claude Code's own sandbox (only /tmp/claude/ is allowed). This causes every git commit to fail on the first attempt.

What Should Happen?

Git commit should succeed on the first attempt. The system prompt should use a sandbox-compatible approach like multiple -m flags instead of heredoc.

Error Messages/Logs

⏺ Bash(git commit -m "feat(claude): add sandbox and permission settings…)
  ⎿  Error: Exit code 1
     (eval):1: can't create temp file for here document: operation not permitted
     Aborting commit due to empty commit message.

Steps to Reproduce

1. Enable sandbox mode in settings:

``json
{
"sandbox": {
"enabled": true
}
}
``

1. Stage some changes with git add
2. Ask Claude to commit the changes
3. Observe the first attempt fails with the error above
4. Claude retries with -m flags and succeeds

Claude Model

Opus

Is this a regression?

I don't know.

Last Working Version

_No response_

Claude Code Version

2.1.9 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Ghostty/zsh

Additional Information

_No response_