Pre commit

PreCommit

A comprehensive skill for managing pre-commit hooks - the framework for multi-language pre-commit hook management that automates code quality, formatting, linting, and security scanning.

Quick Reference

Command	Description
pre-commit install	Install git hooks
pre-commit run --all-files	Run all hooks on all files
pre-commit autoupdate	Update hooks to latest versions
pre-commit run <hook-id>	Run specific hook

Workflow Routing

Workflow	Trigger	File
Setup	"setup pre-commit", "initialize hooks", "create config"	Workflows/Setup.md
AddHooks	"add hook", "add linting", "add formatter", "add security"	Workflows/AddHooks.md
Troubleshoot	"fix pre-commit", "hook failing", "debug hooks"	Workflows/Troubleshoot.md
CIIntegration	"CI pipeline", "GitHub Actions", "GitLab CI"	Workflows/CIIntegration.md
CustomHook	"create custom hook", "local hook", "write hook"	Workflows/CustomHook.md

Documentation

Document	Purpose
QuickStartGuide.md	Installation and first-time setup
HooksReference.md	Comprehensive hook catalog by language/purpose
ConfigurationGuide.md	Advanced configuration options
SecurityHooks.md	Secret detection and security scanning

Tools

Tool	Purpose
Tools/PreCommitManager.ts	CLI for managing pre-commit configurations
Tools/HookGenerator.ts	Generate .pre-commit-config.yaml templates
Tools/HookValidator.ts	Validate hook configurations

Examples

Example 1: Setup pre-commit for a new project

User: "Setup pre-commit for my Python project"
→ Invokes Setup workflow
→ Creates .pre-commit-config.yaml with Python hooks (black, isort, flake8)
→ Runs pre-commit install

Example 2: Add Terraform hooks

User: "Add Terraform validation hooks"
→ Invokes AddHooks workflow
→ Adds terraform_fmt, terraform_validate, terraform_docs hooks
→ Configures tflint and checkov integration

Example 3: Add security scanning

User: "Add secret detection to pre-commit"
→ Invokes AddHooks workflow
→ Adds gitleaks, detect-secrets, trufflehog hooks
→ Configures appropriate exclusion patterns

Example 4: Debug failing hook

User: "My eslint pre-commit hook is failing"
→ Invokes Troubleshoot workflow
→ Checks hook configuration and dependencies
→ Provides fix recommendations

Supported Hook Categories

• Python: black, isort, flake8, mypy, bandit, pyupgrade
• JavaScript/TypeScript: prettier, eslint, biome
• Infrastructure: terraform, terragrunt, helm, kustomize
• Kubernetes: kubeconform, kubeval, checkov
• Security: gitleaks, detect-secrets, trufflehog, trivy
• General: yamllint, jsonlint, shellcheck, markdownlint

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Gotchas

• Hook output disappears when run via git commit -m in an editor terminal — stdout/stderr get swallowed by the editor wrapping. Run pre-commit run --all-files directly to see the actual failure message.
• pre-commit autoupdate bumps to latest tag but doesn't update pinned config in hook repos — a hook that pins flake8==6.0.0 internally keeps that version. Look at each hook's additional_dependencies after autoupdate.
• Hooks only run on staged files by default, so editing a file after git add and then committing runs the hook against the OLD content. Use --all-files in CI to catch this.
• exclude: regex is anchored differently than files: — exclude: tests/ does NOT exclude tests/foo.py in some hook versions; use exclude: ^tests/ to be safe. Anchor everything.
• language: system hooks bypass the pre-commit venv and rely on the user's PATH — works on your machine, fails in CI with command not found. Prefer language: python with additional_dependencies.
• pre-commit install doesn't install for commit-msg or pre-push by default — separate --hook-type calls needed. Many teams add commit-msg hooks then wonder why they don't fire.
• Skipping a hook via SKIP=hookid git commit is per-shell-invocation, not per-commit — CI runs with a fresh env where SKIP is unset and the hook fires anyway.