excludedCommands in sandbox config does not bypass bwrap filesystem restrictions

Description

excludedCommands: ["git"] in settings.json sandbox config does not bypass bwrap filesystem write restrictions. Git commands that need to write (e.g., git add, git commit) fail with "Read-only file system" when the repo is outside the sandbox's writable paths.

Environment

• Claude Code v2.1.56
• bwrap 0.9.0
• Ubuntu 24.04 (WSL2)
• Settings: sandbox.enabled: true, sandbox.excludedCommands: ["git"]

Steps to Reproduce

1. Configure settings.json with:

{
  "sandbox": {
    "enabled": true,
    "excludedCommands": ["git"]
  }
}

1. Set CWD to /home/user (writable by sandbox)
2. Have a git repo at /opt/project (outside sandbox write allowlist)
3. Run: git -C /opt/project add file.txt

Expected Behavior

git should run outside the bwrap sandbox (per excludedCommands docs), allowing writes to /opt/project/.git/.

Actual Behavior

fatal: Unable to create '/opt/project/.git/index.lock': Read-only file system

Even git via a shell script at a writable temp path fails — the sandbox applies filesystem restrictions regardless of excludedCommands.

Workaround

User must run git commands manually outside Claude Code, or via a script in a separate terminal.

Notes

• Read-only git commands (git status, git log, git diff) work fine since they don't write to .git/
• The excludedCommands setting appears to have no observable effect on bwrap mount behavior