commit-message-generator

name	commit-message-generator
description	Generate conventional commit messages from staged git changes. Use when the user asks to commit, create a commit message, write a commit, or wants help with git commits. Analyzes staged diffs and produces structured messages following the Conventional Commits specification.
version	1.0.0
tools	["Bash","Read"]

Commit Message Generator

Generate well-structured conventional commit messages by analyzing staged git changes.

Workflow

1. Check for staged changes Run git diff --cached --stat to see what's staged. If nothing is staged, tell the user and suggest they stage files first.

2. Analyze the diff Run git diff --cached to get the full diff. Read through each file's changes carefully.

3. Determine the commit type Based on the changes, select the appropriate type:

   • feat: New feature or capability
   • fix: Bug fix
   • refactor: Code restructuring without behavior change
   • docs: Documentation only
   • test: Adding or updating tests
   • chore: Build, CI, dependencies, tooling
   • style: Formatting, whitespace, semicolons
   • perf: Performance improvement

4. Determine scope (optional) If the changes are localized to a specific module, component, or area, include a scope: feat(auth): ...

5. Write the subject line

   • Use imperative mood: "add" not "added" or "adds"
   • Keep under 72 characters
   • Don't end with a period
   • Be specific: "add OAuth2 Google login flow" not "update auth"

6. Write the body (if needed) For non-trivial changes, add a body separated by a blank line:

   • Explain WHY, not what (the diff shows what)
   • Wrap at 72 characters
   • Use bullet points for multiple reasons

7. Check for breaking changes If the change breaks backward compatibility, add:

   BREAKING CHANGE: description of what breaks and migration path
   

8. Present the commit message Show the full message to the user and ask for confirmation before committing.

Rules

• Never skip the diff analysis — always base the message on actual changes
• If changes span multiple unrelated concerns, suggest splitting into separate commits
• Always use imperative mood in the subject
• Subject line must be under 72 characters
• Use a HEREDOC for the commit command to preserve formatting
• Include Co-Authored-By if the user requests it

Example Output

feat(auth): add OAuth2 Google login flow

Implement Google OAuth2 authentication using Supabase Auth provider.
Users can now sign in with their Google account in addition to email
magic links.

- Add Google provider configuration in Supabase dashboard
- Create OAuth callback handler at /auth/callback
- Update login page with Google sign-in button