Create Git Commit

Create a git commit with a properly formatted message, working around sandbox heredoc limitations.

Instructions

1. Detect Harness and Model

Determine which AI harness is in use, then detect the model:

# Harness detection
if [ -n "$OPENCODE" ]; then
  HARNESS="opencode"
elif [ -n "$CODEX" ] || [ -n "$CODEX_CLI" ]; then
  HARNESS="codex"
else
  HARNESS="claude"
fi
echo "HARNESS=$HARNESS"

Model detection by harness:

Harness	Detection method
OpenCode	Check the system prompt for "You are powered by the model named X"
Codex	Check the system prompt for model name (e.g. "ChatGPT 5.5")
Claude Code	Check the system prompt for model version (e.g. "Claude Opus 4.7")

Set MODEL to the detected model name (e.g. DeepSeek V4 Pro, ChatGPT 5.5, Claude Opus 4.7).

2. Resolve Attribution

Build the commit footer lines from $HARNESS and $MODEL:

Harness	Generated with	Co-Authored-By
claude	🤖 Generated with [Claude Code](https://claude.com/claude-code)	Co-Authored-By: $MODEL <noreply@anthropic.com>
codex	🤖 Generated with [Codex](https://github.com/openai/codex)	Co-authored-by: codex <codex@users.noreply.github.com>
opencode	🤖 Generated with [OpenCode](https://opencode.ai)	Co-Authored-By: $MODEL <noreply@opencode.ai>

3. Check what to commit

# See status
git status

# See staged changes
git diff --cached --stat

# See recent commits for style reference
git log --oneline -5

# Extract Linear ticket ID from branch name (if present)
git branch --show-current | grep -oiE 'thr-[0-9]+' | tr '[:lower:]' '[:upper:]'

4. Write the commit message to a temp file

Use .tmp/ (gitignored, no sandbox approval needed):

mkdir -p .tmp

# Single-line message
printf '%s\n' 'type: short description' > .tmp/commit-msg.txt

# Multi-line message (each line as a separate argument)
printf '%s\n' \
  'type: short description' \
  '' \
  '- Detail 1' \
  '- Detail 2' \
  '' \
  '🤖 Generated with [OpenCode](https://opencode.ai)' \
  '' \
  'Co-Authored-By: DeepSeek V4 Pro <noreply@opencode.ai>' \
  > .tmp/commit-msg.txt

5. Stage and commit

# Stage specific files (never use git add .)
git add path/to/file1.ts path/to/file2.ts

# Commit using the file
git commit -F .tmp/commit-msg.txt

6. Clean up

rm -rf .tmp

Commit Message Format

Follow conventional commits with Linear ticket ID when available:

• feat(THR-XX): - New feature
• fix(THR-XX): - Bug fix
• refactor(THR-XX): - Code restructuring
• docs(THR-XX): - Documentation
• test(THR-XX): - Tests
• chore(THR-XX): - Maintenance

If no Linear ticket exists, omit the parenthetical: feat: description

The harness attribution footer is resolved dynamically per section 2 above.

Common Issues

Heredoc fails with "can't create temp file": This is expected in sandbox mode. Use printf approach instead.

Sandbox approval for /tmp writes: Use .tmp/ inside the repo (already gitignored) to avoid sandbox prompts.

Special characters in message: Use single quotes to prevent shell expansion. For apostrophes, end the quote, add escaped apostrophe, restart quote:

printf '%s\n' "Don't do this" > .tmp/commit-msg.txt

Examples

Simple commit (OpenCode example):

mkdir -p .tmp
printf '%s\n' 'fix: correct typo in README' '' '🤖 Generated with [OpenCode](https://opencode.ai)' '' 'Co-Authored-By: DeepSeek V4 Pro <noreply@opencode.ai>' > .tmp/commit-msg.txt
git add README.md && git commit -F .tmp/commit-msg.txt

Multi-line commit (Codex example):

mkdir -p .tmp
printf '%s\n' \
  'refactor: extract helper function' \
  '' \
  '- Moved validation logic to separate function' \
  '- Added unit tests' \
  '- Updated callers' \
  '' \
  '🤖 Generated with [Codex](https://github.com/openai/codex)' \
  '' \
  'Co-authored-by: codex <codex@users.noreply.github.com>' \
  > .tmp/commit-msg.txt
git add src/utils.ts src/utils.test.ts && git commit -F .tmp/commit-msg.txt