Git Expert

Git Expert

Overview

Expert git workflow skill covering isolation (worktrees), commits, branching, and PR submission using GitHub CLI (gh).

Core principles:

• Isolation: Work in worktrees to avoid context pollution
• Atomic commits: Each commit represents one logical change
• Verification: Always verify before committing or pushing
• Clean history: Meaningful commits, clean rebases

Sub-Skills

This skill contains three sub-skills for different phases:

1. Worktrees - Feature isolation and workspace setup
2. Commits - Intelligent commit protocol
3. Finishing - Branch completion and PR submission

1. Git Worktrees

When to Use

• Starting feature work that needs isolation
• Before executing implementation plans
• Working on multiple branches simultaneously
• Need clean baseline without affecting main workspace

Directory Selection Process

Follow this priority:

# 1. Check existing directories
ls -d .worktrees 2>/dev/null     # Preferred (hidden)
ls -d worktrees 2>/dev/null      # Alternative

# 2. Check CLAUDE.md for preference
grep -i "worktree.*director" CLAUDE.md 2>/dev/null

# 3. If neither exists, ask user

Safety Verification

MUST verify directory is ignored before creating worktree:

git check-ignore -q .worktrees 2>/dev/null

If NOT ignored:

1. Add to .gitignore: echo '.worktrees/' >> .gitignore
2. Commit the change
3. Proceed with worktree creation

Creation Steps

# 1. Get project name
project=$(basename "$(git rev-parse --show-toplevel)")

# 2. Create worktree with new branch
git worktree add .worktrees/$BRANCH_NAME -b feature/$BRANCH_NAME

# 3. Move to worktree
cd .worktrees/$BRANCH_NAME

# 4. Auto-detect and run setup
if [ -f package.json ]; then npm install; fi
if [ -f Cargo.toml ]; then cargo build; fi
if [ -f requirements.txt ]; then pip install -r requirements.txt; fi
if [ -f go.mod ]; then go mod download; fi

# 5. Verify clean baseline
npm test  # or project-appropriate test command

Worktree Commands

2. Git Commits

Core Rules

Never do without explicit permission:

• Push to remote
• Force push
• Run git clean -fdx
• Modify git config
• Amend pushed commits

Always do:

• Include meaningful commit messages
• Check status before operations
• Verify tests pass before committing
• Use HEREDOC for multi-line messages

Pre-Commit Protocol

# 1. Status check
git status

# 2. Pre-commit validation (if available)
npm run lint && npm run typecheck

# 3. Run tests
npm test

# 4. Review changes
git diff --cached

Commit Message Format

Format: {type}: {summary}

Types:

• feat: New feature
• fix: Bug fix
• refactor: Code restructuring
• docs: Documentation
• style: Formatting
• test: Tests
• build: Build system
• chore: Maintenance

Examples:

git commit -m "feat: add user profile endpoint"
git commit -m "fix: resolve race condition in auth flow"
git commit -m "refactor: extract validation helpers"

Multi-Line Commit Messages

Use HEREDOC for complex messages:

git commit -m "$(cat <<'EOF'
feat: implement retry mechanism for API calls

- Add exponential backoff with jitter
- Configure max retries via environment variable
- Add comprehensive test coverage

Closes #123
EOF
)"

Staged vs Unstaged

# See what's staged
git diff --cached --name-only

# See what's unstaged
git diff --name-only

# Stage related files together
git add src/auth/* tests/auth/*

# Stage hunks interactively (if needed)
git add -p

Verification Before Commit

MANDATORY before every commit:

# 1. Run tests
npm test  # Must pass

# 2. Run linter
npm run lint  # Must be clean

# 3. Type check (if applicable)
npm run typecheck  # Must pass

# 4. Review staged changes
git diff --cached

3. Finishing a Development Branch

When to Use

• Implementation complete
• All tests pass
• Ready to integrate work

The Process

Step 1: Verify Tests

npm test  # Must pass before proceeding

If tests fail, stop. Fix before continuing.

Step 2: Determine Base Branch

git merge-base HEAD main 2>/dev/null || git merge-base HEAD master

Step 3: Present Options

Implementation complete. What would you like to do?

1. Merge back to <base-branch> locally
2. Push and create a Pull Request
3. Keep the branch as-is (I'll handle it later)
4. Discard this work

Which option?

Option 1: Merge Locally

git checkout main
git pull
git merge feature/my-feature
npm test  # Verify after merge
git branch -d feature/my-feature

Then cleanup worktree.

Option 2: Create PR (Standard Git)

git push -u origin feature/my-feature

gh pr create --title "Add feature X" --body "$(cat <<'EOF'
## Summary
- Implemented X
- Added tests for Y

## Test Plan
- [ ] Unit tests pass
- [ ] Integration tests pass
EOF
)"

Option 3: Keep As-Is

Report status. Don't cleanup.

Option 4: Discard

Require confirmation:

This will permanently delete:
- Branch feature/my-feature
- All commits: abc123, def456
- Worktree at .worktrees/my-feature

Type 'discard' to confirm.

git checkout main
git branch -D feature/my-feature
git worktree remove .worktrees/my-feature

Branch Naming

Protected Branches

• main / master: Production (never direct push)
• develop / dev: Development/staging

Always create feature branches from the appropriate base.

Common Mistakes

Skipping verification

• Problem: Commit broken code
• Fix: Always run tests before commit

Force push without warning

• Problem: Overwrite others' work
• Fix: Never force push without explicit permission

Worktree not ignored

• Problem: Worktree contents tracked in git
• Fix: Always verify .worktrees/ is in .gitignore

Committing secrets

• Problem: Expose credentials
• Fix: Check for .env, credentials files before staging

Vague commit messages

• Problem: Unclear history
• Fix: Use type prefix, describe the "why"

Red Flags - STOP

Never:

• Push without explicit request
• Force push (especially to main/master)
• Commit without tests passing
• Delete branches without confirmation
• Proceed with failing tests

Always:

• Verify tests before commit
• Use meaningful commit messages
• Check what's staged before committing
• Get confirmation for destructive operations

Quick Reference

# Worktree setup
git worktree add .worktrees/feature -b feature/name
cd .worktrees/feature && npm install && npm test

# Commit workflow
git status
npm test && npm run lint
git add <files>
git commit -m "type: description"

# Standard PR
git push -u origin feature/name
gh pr create

# Cleanup
git worktree remove .worktrees/feature
git branch -d feature/name

Integration

On-demand loading: This is a Domain skill, loaded when git operations detected.

Pairs with:

• tdd - Tests pass before commits
• verification - Verify before PR submission
• subagent-driven-development - Feature branches for sub-agent work