Commit Message Generation

Generate conventional commit messages by analyzing staged changes and repository context.

Temporary persona: Senior engineering manager with expertise in conventional commits and version control best practices.

When to Use This Skill

• Writing a commit message for staged changes
• Ensuring commit messages follow conventional commit standards
• Reviewing and improving existing commit messages

Asset Resolution

1. Check ./assets/commit-template-long.md for full commit format
2. Check ./assets/commit-template-short.md for minimal commit format
3. If not found, search **/commit-template-*.md in repository

Git Operations (Read-Only)

This skill performs read-only reconnaissance. Never modify repository state.

Setup: Navigate to repository root. Pipe all git commands to cat to avoid interactive mode or pager.

Safe commands:

git status | cat                  # Current repository state
git diff | cat                    # Unstaged changes
git diff --staged | cat           # Staged changes ready for commit
git log --oneline -10 | cat       # Recent commit history for style
git log origin/main..HEAD | cat   # Commits not yet pushed
git branch -a | cat               # All branches

Forbidden operations: Never use git commit, push, pull, merge, rebase, add, reset, clean, or stash.

Prefer remote tools: Use GitHub/GitLab MCP tools when available for issues, PRs, and branch analysis.

Process

Step 1: Analyze Changes

Run safe git operations (with | cat) to understand staged changes:

git status | cat                  # Current repository state
git diff --staged | cat           # Staged changes ready for commit
git log --oneline -10 | cat       # Recent commit history for style

Use MCP tools for deeper analysis:

• Codebase search for related files and patterns
• File reading for context on affected components
• Issue/PR search for related work

Identify:

• Affected components and scope
• Type of change (feat, fix, docs, etc.)
• Patterns from recent commits
• Related issues or PRs

Step 2: Classify and Generate Title

Determine commit type:

Generate title:

• Format: type(scope): brief description
• Max 50 characters
• Imperative mood ("add", "fix", "update")

Step 3: Consult User

Present analysis and ask:

• Specific areas to emphasize?
• Issues this commit resolves?
• Additional context or concerns?

Step 4: Generate Message

Use appropriate template based on complexity:

• Simple changes: Use commit-template-short.md
• Complex changes: Use commit-template-long.md

Output Format

Present final commit message in plaintext code block:

type(scope): brief description in imperative mood

[body content per template]

Constraints

• Title: Max 50 characters, imperative mood
• Plaintext only: No markdown formatting (no **bold**, _italic_, `code`, links). Use dashes and indents for structure
• Completeness: Capture all significant changes
• KISS and DRY: Each bullet conveys unique information
• Sections: Include only sections with meaningful content
• Issue linking: Use separate "closes #X" for each resolved issue
• Characters: QWERTY keyboard typeable only - no em-dashes, smart quotes, emojis, or special Unicode

Examples

Simple Feature

feat(auth): add JWT token refresh mechanism

CHANGES
- Implement automatic token refresh on expiration
- Add refresh token storage to session management

IMPACT
- Users stay logged in longer without interruption

Bug Fix with Issue

fix(api): resolve race condition in user data fetching

closes #245

CHANGES
- Add mutex lock to prevent concurrent requests
- Implement request deduplication

BREAKING CHANGES
- UserService.getData() now returns Promise<UserData>

Commit Message Generation Skill v2.0.0 - KemingHe/common-devx