Commit Message Generator

Description

Analyze staged changes and generate conventional commit messages. Supports Conventional Commits, GitHub-style, and custom formats. Can also review existing commit history for consistency.

Triggers

• "Generate commit message", "Write commit message", "Commit this"
• "What should I commit?", "Review my changes"
• "Commit message for this PR", "Squash and rewrite commits"

Instructions

Step 1: Analyze Changes

1. Run git diff --cached to see staged changes
2. If nothing staged, run git diff and git status to show unstaged changes
3. For PR reviews, use git log --oneline origin/main..HEAD to see all commits

Step 2: Categorize Changes

Map changes to conventional commit types:

• feat: New feature, new API endpoint, new component
• fix: Bug fix, error handling, edge case
• refactor: Code restructure without behavior change
• perf: Performance improvement
• docs: Documentation only
• style: Formatting, whitespace, semicolons
• test: Adding/updating tests
• chore: Build, CI, dependencies, tooling
• ci: CI/CD configuration changes
• revert: Reverting a previous commit

Step 3: Generate Message

Format (Conventional Commits):

<type>(<scope>): <subject>

<body>

<footer>

Rules:

• Subject: imperative mood, lowercase, no period, max 72 chars
• Body: explain what and why, not how, wrap at 72 chars
• Footer: breaking changes (BREAKING CHANGE:), issue refs (Closes #123)
• If multiple unrelated changes, suggest splitting into separate commits

Step 4: Multi-commit Suggestion

If staged changes span multiple concerns:

Suggested split:
1. feat(auth): add OAuth2 login flow
2. fix(api): handle null response in user endpoint
3. chore(deps): update axios to 1.7.0

Run these commands:
  git reset HEAD
  git add src/auth/oauth.py
  git commit -m "feat(auth): add OAuth2 login flow"
  git add src/api/users.py
  git commit -m "fix(api): handle null response in user endpoint"
  git add package.json package-lock.json
  git commit -m "chore(deps): update axios to 1.7.0"

PR Description Mode

When asked to write a PR description:

1. Read all commits in the branch
2. Categorize by type
3. Generate:
   • Summary (2-3 sentences)
   • Changes (grouped by category)
   • Testing notes
   • Breaking changes (if any)
   • Checklist

Output Format

Provide 3 options: concise (subject only), standard (subject + body), detailed (subject + body + footer). Default to standard unless user specifies otherwise.

Constraints

• Never auto-commit without user confirmation
• For sensitive changes (secrets, auth), add a warning in the footer
• If changes are too large (>20 files), suggest a descriptive PR instead