pre-commit — A Framework for Managing Git Hook Scripts

What it is

pre-commit is a framework for managing and installing multi-language Git hooks. It reads a .pre-commit-config.yaml file and runs configured hooks (linters, formatters, security checks) before each commit.

pre-commit targets development teams who want to catch issues locally before code reaches CI. It supports hooks written in Python, Node.js, Go, Rust, Ruby, and more -- all managed from one config file.

How it saves time or tokens

pre-commit catches formatting errors, trailing whitespace, YAML syntax issues, and linting violations before they become CI failures. This eliminates round-trip time waiting for remote CI to flag trivial issues. New developers get all hooks installed with a single pre-commit install command.

How to use

1. Install pre-commit and initialize hooks:

pip install pre-commit
pre-commit install
pre-commit run --all-files

1. Create a .pre-commit-config.yaml in your repo root.

1. Commit as normal. Hooks run automatically on each git commit.

Example

# .pre-commit-config.yaml
repos:
  - repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v4.6.0
    hooks:
      - id: trailing-whitespace
      - id: end-of-file-fixer
      - id: check-yaml
  - repo: https://github.com/astral-sh/ruff-pre-commit
    rev: v0.6.9
    hooks:
      - id: ruff
        args: [--fix]
      - id: ruff-format
  - repo: https://github.com/pre-commit/mirrors-prettier
    rev: v3.1.0
    hooks:
      - id: prettier
        types_or: [javascript, typescript, json, yaml, markdown]

Related on TokRepo

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Common pitfalls

• Hook environments are cached in ~/.cache/pre-commit/. Clear this cache if hooks behave unexpectedly after version updates.
• Large repos may experience slow hook runs. Use the files or exclude regex in hook config to limit scope.
• pre-commit hooks run on staged files only by default. Use pre-commit run --all-files for full-repo checks in CI.