Commit Message Skill

Generate consistent, informative commit messages following the Conventional Commits specification.

When to Use This Skill

• User asks to "commit", "write a commit message", or "prepare commit"
• User has staged changes and mentions commits
• Before any git commit command

Process

1. Analyze changes: Run git diff --staged to see what's being committed
2. Identify the type: Determine the primary change category
3. Find the scope: Identify the main area affected
4. Write the message: Follow the format below

Commit Message Format

<type>(<scope>): <description>

[optional body]

[optional footer(s)]

Types

Type	Description	Example
feat	New feature	feat(auth): add OAuth2 login
fix	Bug fix	fix(api): handle null response
docs	Documentation only	docs(readme): add setup instructions
style	Formatting, no code change	style: fix indentation
refactor	Code change, no new feature/fix	refactor(db): extract query builder
perf	Performance improvement	perf(search): add result caching
test	Adding/fixing tests	test(auth): add login unit tests
build	Build system changes	build: update webpack config
ci	CI configuration	ci: add GitHub Actions workflow
chore	Maintenance tasks	chore(deps): update dependencies
revert	Revert previous commit	revert: feat(auth): add OAuth2

Scope

The scope should be a noun describing the section of the codebase:

• auth, api, db, ui, config
• Feature names: search, checkout, dashboard
• Or omit if change is broad

Subject Line Rules

• Use imperative mood: "add" not "added" or "adds"
• Don't capitalize first letter after colon
• No period at the end
• Max 72 characters total

Body (when needed)

• Separate from subject with blank line
• Explain what and why, not how
• Wrap at 72 characters
• Use bullet points for multiple changes

Footer (when needed)

• BREAKING CHANGE: for breaking changes
• Fixes #123 to close issues
• Refs #456 to reference without closing

Examples

Simple feature

feat(search): add fuzzy matching support

Implement Levenshtein distance algorithm for typo tolerance
in search queries. Configurable via FUZZY_THRESHOLD env var.

Bug fix with issue reference

fix(cart): prevent duplicate items on rapid clicks

Add debounce to add-to-cart button and check for existing
items before insertion.

Fixes #234

Breaking change

feat(api)!: change response format to JSON:API

BREAKING CHANGE: API responses now follow JSON:API spec.
All clients need to update their parsers.

- Wrap data in `data` object
- Move metadata to `meta` object  
- Add `links` for pagination

Multiple related changes

refactor(auth): consolidate authentication logic

- Extract JWT handling to dedicated service
- Move session management from controller to middleware
- Add refresh token rotation

This prepares for the upcoming OAuth2 integration.

Output

When generating a commit message:

1. Show the staged changes summary
2. Propose the commit message
3. Explain the type/scope choice if non-obvious
4. Ask if the user wants to proceed or modify