| name | setup-pre-commit |
| description | Set up repository-local Husky pre-commit hooks with lint-staged, Prettier, and optional typecheck/test gates. Use when a user asks to add pre-commit hooks, configure lint-staged, enforce staged formatting, or add commit-time checks. |
setup-pre-commit
Guides a safe, repo-aware pre-commit setup. This skill is guidance-first: inspect the target repository, explain the planned changes, and only mutate dependency, hook, package, lint-staged, or Prettier files after the user approves that setup.
What this configures
- Husky v9+ with a
.husky/pre-commit hook
- lint-staged running Prettier on staged files
- Prettier defaults only when no Prettier config exists
- Optional
typecheck and test commands only when the target package.json already defines those scripts
- Verification commands and a real commit smoke test when the user is ready to commit setup changes
1. Preflight the target repo
Work from the target repo root, then inspect existing package and config state before proposing commands:
git status --short
node -e "const fs=require('fs'); const p=JSON.parse(fs.readFileSync('package.json','utf8')); process.stdout.write(JSON.stringify({packageManager:p.packageManager||null,scripts:p.scripts||{}}, null, 2)+'\n');"
node -e "const fs=require('fs'); const files=['bun.lock','bun.lockb','pnpm-lock.yaml','yarn.lock','package-lock.json','.lintstagedrc','.lintstagedrc.json','.lintstagedrc.js','lint-staged.config.js','.prettierrc','.prettierrc.json','.prettierrc.js','prettier.config.js','prettier.config.cjs','prettier.config.mjs']; process.stdout.write(files.filter((f)=>fs.existsSync(f)).join('\n')+'\n');"
Stop and ask before editing if the repo has unrelated dirty changes, multiple package managers, or an existing hook/config whose intent is unclear.
2. Detect the package manager
Prefer the packageManager field in package.json, then lockfiles:
| Signal | Package manager |
|---|
packageManager starts with bun or bun.lock / bun.lockb exists | Bun |
packageManager starts with pnpm or pnpm-lock.yaml exists | pnpm |
packageManager starts with yarn or yarn.lock exists | Yarn |
packageManager starts with npm or package-lock.json exists | npm |
If there is no clear signal, default to npm only after telling the user that no lockfile or package-manager pin was found.
3. Install dev dependencies
Use exactly one command for the detected package manager:
| Package manager | Command |
|---|
| Bun | bun add --dev husky lint-staged prettier |
| pnpm | pnpm add --save-dev husky lint-staged prettier |
| Yarn | yarn add --dev husky lint-staged prettier --non-interactive |
| npm | npm install --save-dev husky lint-staged prettier --yes |
Do not run these commands while porting this skill. Run them only when applying the skill to a target repo with user approval.
4. Initialize Husky
After dependencies are installed, initialize Husky with the detected package manager:
| Package manager | Command |
|---|
| Bun | bunx --bun husky init |
| pnpm | pnpm exec husky init |
| Yarn | yarn exec husky init |
| npm | npx --yes husky init |
Husky v9+ creates .husky/pre-commit and usually adds prepare: "husky" to package.json. Preserve an existing prepare script by combining commands only if the user approves the exact package script change.
5. Compose .husky/pre-commit
The hook must run lint-staged first, then only the package scripts that already exist. Do not add failing placeholder lines for missing scripts.
| Package manager | lint-staged line | Existing typecheck script | Existing test script |
|---|
| Bun | bunx --bun lint-staged | bun run typecheck | bun run test |
| pnpm | pnpm exec lint-staged | pnpm run typecheck | pnpm run test |
| Yarn | yarn exec lint-staged | yarn run typecheck | yarn run test |
| npm | npx --no-install lint-staged | npm run typecheck | npm run test |
Example for a Bun repo that has both scripts:
bunx --bun lint-staged
bun run typecheck
bun run test
If the repo lacks typecheck or test, omit that line and tell the user which check was skipped.
6. Configure lint-staged and Prettier
Respect existing config:
- If a lint-staged config already exists, update it only after confirming it should run Prettier on staged files.
- If no lint-staged config exists, add one config location that matches repo style. Prefer an existing
package.json config style if the repo already keeps tool config there; otherwise use .lintstagedrc.json.
- Use this minimal lint-staged config:
{
"*": "prettier --ignore-unknown --write"
}
- If any Prettier config exists, do not overwrite it.
- If no Prettier config exists, propose these defaults:
{
"useTabs": false,
"tabWidth": 2,
"printWidth": 80,
"singleQuote": false,
"trailingComma": "es5",
"semi": true,
"arrowParens": "always"
}
prettier --ignore-unknown lets staged binary or unsupported files pass without parse failures.
7. Verify
Run only commands that match the detected package manager and existing scripts:
git status --short
- Confirm
.husky/pre-commit exists and contains the selected lint-staged line.
- Confirm
package.json has a valid Husky prepare script without clobbering previous behavior.
- Confirm lint-staged config exists and Prettier config is preserved or created intentionally.
- Run the selected lint-staged command with staged setup files.
- Run the selected typecheck/test commands only if those scripts exist.
8. Smoke test with a real commit
When the user is ready to commit the setup, use the normal commit as the smoke test:
git add package.json .husky/pre-commit .lintstagedrc.json .prettierrc
git commit -m "chore: add pre-commit checks"
Adjust the git add paths to the files actually changed. Do not create an empty or throwaway commit just to test the hook, and do not run a commit smoke test unless the user explicitly wants the setup committed.
