Commit Messages

Generate commit messages that are compact, clear, and follow the Conventional Commits specification.

Format

<type>[optional scope]: <description>

[optional body]

[optional footer(s)]

Key rules:

• Use imperative mood in description ("add" not "added" or "adds")
• No capitalization of first letter in description
• No period at end of description
• Keep description under 72 characters
• Use body only when needed for context

Types

Type	Usage	Example
feat	New feature	feat: add user authentication
fix	Bug fix	fix: resolve null pointer in login
docs	Documentation only	docs: update API endpoints
style	Formatting, no code change	style: format indentation
refactor	Code change without fix/feature	refactor: extract utility function
test	Adding/updating tests	test: add unit tests for auth
chore	Build, CI, dependencies	chore: bump dependencies
perf	Performance improvement	perf: optimize query execution
ci	CI/CD configuration	ci: add GitHub Actions workflow
build	Build system changes	build: update webpack config
revert	Revert previous commit	revert: remove broken feature

Scope (Optional)

Scope indicates the affected module or component:

feat(auth): add OAuth2 support
fix(api): handle timeout errors
docs(readme): add installation steps

Keep scope short - typically one word.

Breaking Changes

For breaking changes, add ! after type/scope or include BREAKING CHANGE: in footer:

feat!: redesign API endpoints

BREAKING CHANGE: all endpoints now require authentication

Style Guidelines

Do

• Be specific and descriptive
• Explain "what" and "why", not "how"
• Use imperative mood
• Keep it compact

Don't

• Don't use vague messages ("fix bug", "update code")
• Don't describe implementation details
• Don't exceed 72 characters in description
• Don't capitalize description start

Examples

Good Examples

feat: add password reset functionality
fix: resolve memory leak in worker process
docs: clarify installation requirements
refactor(search): extract ranking algorithm
test: add edge cases for date parser
chore(deps): bump eslint to 9.0.0
feat(api)!: change response format to JSON

Bad Examples

Fixed the bug                          # Past tense, vague
Added new feature for user login.      # Capitalized, period
feat: I added a new login page         # First person
fix: fix the thing                     # Vague, not descriptive
updates to the codebase                # No type, vague
feat(authentication-system): add oauth # Scope too long

Process for Generating Commits

1. Analyze changes: Review staged files with git diff --staged
2. Identify type: Determine the primary change category
3. Add scope: If changes are focused on specific module
4. Write description: Compact summary in imperative mood
5. Add body: Only if additional context is necessary

Multi-line Commits

Use body for additional context when the change is complex.

When to Add Body

Add body when ANY of these conditions are met:

Condition	Threshold	Example
Large changes	>100 lines OR >5 files	Refactoring multiple modules
Complex logic	Non-obvious changes	Bug fixes, algorithm changes
Breaking changes	API changes, config updates	Removing deprecated endpoints
Multiple concerns	More than one focus	Fix + refactor in same commit

Keep description-only when:

• Single file, small changes (<50 lines)
• Simple, self-explanatory modifications
• Typo fixes, minor doc updates

Body Structure

When adding body, include:

1. What: Brief summary of changes
2. Why: Motivation and context
3. Impact: Breaking changes or migration notes (if any)

feat(api): add rate limiting to public endpoints

Implement token bucket algorithm for all public API endpoints.
Limit: 100 requests per minute per IP address.

This protects against abuse while maintaining compatibility
with existing clients.

Examples

Simple change (no body needed):

fix: resolve typo in login error message

Complex change (body required):

fix(auth): resolve race condition in token refresh

The concurrent refresh issue occurred when multiple tabs
tried to refresh expired tokens simultaneously. Now uses
mutex lock to serialize refresh requests.

Fixes #456

Related Commits

When referencing issues or PRs:

fix: resolve race condition in worker

The concurrent access issue occurred when multiple workers tried to
update the same cache entry simultaneously.

Fixes #456

Co-Authored-By Footer

Rule: No AI Attribution

Never add Co-Authored-By footer for AI agents (Claude Code, GitHub Copilot, OpenAI Codex, Cursor, etc.).

AI is a tool, not a co-author. The human takes full ownership of every commit in their repository.

feat: add user dashboard

Implement dashboard with analytics widgets and real-time updates.

Human Ownership

All commits are attributed to the human user, regardless of AI assistance. This ensures:

• Clean git history without tool attribution
• Human maintains full responsibility for code changes
• Simpler commit messages focused on content, not tools

When Co-Authored-By IS Appropriate

Only use Co-Authored-By for human collaborators:

feat: add user dashboard

Co-Authored-By: Jane Doe <jane@example.com>