name: Git Commit Helper description: Generate descriptive commit messages by analyzing git diffs. Use when the user asks for help writing commit messages or reviewing staged changes. hooks: PostToolUse: - matcher: "Bash" hooks: - type: command command: "echo "[$(date)] Git Commit Helper: Analyzed git diff for commit message" >> ~/.claude/git-commit-helper.log"

Git Commit Helper

Quick start

Analyze staged changes and generate commit message:

# View staged changes
git diff --staged

# Generate commit message based on changes
# (Claude will analyze the diff and suggest a message)

Commit message format

Follow conventional commits format:

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

[optional body]

[optional footer]

Types

• feat: New feature
• fix: Bug fix
• docs: Documentation changes
• style: Code style changes (formatting, missing semicolons)
• refactor: Code refactoring
• test: Adding or updating tests
• chore: Maintenance tasks

Examples

Feature commit:

feat(auth): add JWT authentication

Implement JWT-based authentication system with:
- Login endpoint with token generation
- Token validation middleware
- Refresh token support

Bug fix:

fix(api): handle null values in user profile

Prevent crashes when user profile fields are null.
Add null checks before accessing nested properties.

Refactor:

refactor(database): simplify query builder

Extract common query patterns into reusable functions.
Reduce code duplication in database layer.

Analyzing changes

Review what's being committed:

# Show files changed
git status

# Show detailed changes
git diff --staged

# Show statistics
git diff --staged --stat

# Show changes for specific file
git diff --staged path/to/file

Commit message guidelines

DO:

• Use imperative mood ("add feature" not "added feature")
• Keep first line under 50 characters
• Capitalize first letter
• No period at end of summary
• Explain WHY not just WHAT in body

DON'T:

• Use vague messages like "update" or "fix stuff"
• Include technical implementation details in summary
• Write paragraphs in summary line
• Use past tense

Multi-file commits

When committing multiple related changes:

refactor(core): restructure authentication module

- Move auth logic from controllers to service layer
- Extract validation into separate validators
- Update tests to use new structure
- Add integration tests for auth flow

Breaking change: Auth service now requires config object

Scope examples

Frontend:

• feat(ui): add loading spinner to dashboard
• fix(form): validate email format

Backend:

• feat(api): add user profile endpoint
• fix(db): resolve connection pool leak

Infrastructure:

• chore(ci): update Node version to 20
• feat(docker): add multi-stage build

Breaking changes

Indicate breaking changes clearly:

feat(api)!: restructure API response format

BREAKING CHANGE: All API responses now follow JSON:API spec

Previous format:
{ "data": {...}, "status": "ok" }

New format:
{ "data": {...}, "meta": {...} }

Migration guide: Update client code to handle new response structure

Template workflow

1. Review changes: git diff --staged
2. Identify type: Is it feat, fix, refactor, etc.?
3. Determine scope: What part of the codebase?
4. Write summary: Brief, imperative description
5. Add body: Explain why and what impact
6. Note breaking changes: If applicable

Interactive commit helper

Use git add -p for selective staging:

# Stage changes interactively
git add -p

# Review what's staged
git diff --staged

# Commit with message
git commit -m "type(scope): description"

Amending commits

Fix the last commit message:

# Amend commit message only
git commit --amend

# Amend and add more changes
git add forgotten-file.js
git commit --amend --no-edit

Best practices

1. Atomic commits - One logical change per commit
2. Test before commit - Ensure code works
3. Reference issues - Include issue numbers if applicable
4. Keep it focused - Don't mix unrelated changes
5. Write for humans - Future you will read this

Commit message checklist

• Type is appropriate (feat/fix/docs/etc.)
• Scope is specific and clear
• Summary is under 50 characters
• Summary uses imperative mood
• Body explains WHY not just WHAT
• Breaking changes are clearly marked
• Related issue numbers are included