Git Hooks Skill

When to Activate

Activate this skill when:

• Setting up pre-commit hooks
• Configuring commit message validation
• Installing secrets scanners
• Enforcing code quality standards
• Automating pre-push tests

Quick Installation

# Use interactive installer (recommended)
./AgentUsage/pre_commit_hooks/install_hooks.sh

# Or manual installation for Python project
cp AgentUsage/pre_commit_hooks/commit-msg .git/hooks/
cp AgentUsage/pre_commit_hooks/pre-commit-python .git/hooks/pre-commit
cp AgentUsage/pre_commit_hooks/pre-commit-secrets-scanner .git/hooks/pre-commit-secrets
cp AgentUsage/pre_commit_hooks/pre-push .git/hooks/
chmod +x .git/hooks/*

Available Hooks

Core Hooks (All Projects)

Hook	Purpose
commit-msg	Validates conventional commit format
pre-commit-secrets-scanner	Prevents leaked API keys/secrets

Language-Specific

Hook	Language	Checks
pre-commit-python	Python	Black, Ruff
pre-commit-javascript	JS/TS	Prettier, ESLint, TypeScript
pre-commit-go	Go	gofmt, go vet
pre-commit-multi-language	Mixed	Auto-detects and runs appropriate tools

Automation Hooks

Hook	Purpose
pre-push	Runs tests before push
post-checkout	Auto-updates dependencies on branch switch
post-commit	Shows commit summary and TODOs

Hook Selection by Project

# Python Project
commit-msg + pre-commit-python + pre-commit-secrets-scanner + pre-push

# JavaScript Project
commit-msg + pre-commit-javascript + pre-commit-secrets-scanner + pre-push

# Go Project
commit-msg + pre-commit-go + pre-commit-secrets-scanner + pre-push

# Multi-language
commit-msg + pre-commit-multi-language + pre-commit-secrets-scanner + pre-push

What Each Hook Does

commit-msg

Validates commit message format:

# Accepted formats
feat: Add user authentication
fix: Correct validation error
docs(readme): Update installation

# Rejected
Update files  # No type
feat add feature  # Missing colon

pre-commit-secrets-scanner

Scans for exposed secrets:

• Anthropic API keys (sk-ant-...)
• OpenAI API keys (sk-...)
• AWS credentials (AKIA...)
• GitHub tokens (ghp_...)
• Hardcoded passwords

pre-commit-python

# Runs automatically on staged .py files
uv run black --check $file
uv run ruff check $file

pre-push

# Runs before push
uv run pytest tests/  # or pnpm test, go test, cargo test

Testing Hooks

# Test pre-commit directly
.git/hooks/pre-commit

# Test with sample commit
git add .
git commit -m "test: verify hooks"

# Run with debug output
bash -x .git/hooks/pre-commit

Bypassing Hooks (Emergency Only)

# Skip all hooks
git commit --no-verify -m "Emergency fix"

# Only use when:
# - Emergency production fixes
# - Hook malfunction
# - Intentional override

Troubleshooting

Hook Not Running

# Check existence
ls -l .git/hooks/

# Fix permissions
chmod +x .git/hooks/*

# Check syntax
bash -n .git/hooks/pre-commit

Permission Denied

chmod +x .git/hooks/*

Failed Quality Checks

# Run tools manually
uv run black --check .
uv run ruff check .

# Fix issues
uv run black .
uv run ruff check --fix .

# Retry commit
git commit -m "Your message"

Missing Tools

# Install code quality tools
uv add --dev black ruff

# Verify installation
which black
uv run black --version

Custom Hook Configuration

Modify pre-commit for Your Project

#!/bin/bash
# .git/hooks/pre-commit

# Get staged Python files
FILES=$(git diff --cached --name-only --diff-filter=ACM | grep '\.py$')

if [ -n "$FILES" ]; then
    # Run your tools
    uv run black --check $FILES || exit 1
    uv run ruff check $FILES || exit 1
fi

exit 0

Hook Execution Order

1. pre-commit - Before commit (code quality)
2. commit-msg - Validates message format
3. post-commit - After commit (notifications)
4. pre-push - Before push (tests)

Best Practices

DO ✅

• Install secrets scanner on ALL projects
• Use commit-msg for consistent history
• Run tests in pre-push
• Test hooks after installation

DON'T ❌

• Skip hooks regularly
• Disable secrets scanning
• Ignore hook failures
• Commit without testing hooks first

Related Resources

See AgentUsage/pre_commit_hooks/ for:

• setup_guide.md - Complete installation guide
• examples.md - Custom hook examples
• TROUBLESHOOTING.md - Common issues
• Individual hook scripts for reference