code-quality

Original：🇺🇸 English

Translated

Set up formatting, linting, import sorting, type checking, and pre-commit hooks when scaffolding or starting a new project. Use this skill whenever creating a new project, initializing a repo, scaffolding an app, or when the user asks to add linting/formatting to an existing project. Triggers on: "new project", "scaffold", "init", "set up linting", "add formatter", "add pre-commit hooks", "configure biome", "configure ruff". The goal is to establish code quality tooling from day one so issues are caught incrementally, not in a painful bulk-fix later.

1installs

Sourcerarestg/rarestg-skills

Added on2026-02-08

NPX Install

npx skill4agent add rarestg/rarestg-skills code-quality

SKILL.md Content

View Translation Comparison →

Code Quality Setup

When starting or scaffolding any project, set up formatting, linting, import sorting, type checking, and pre-commit hooks before writing application code. This prevents the painful scenario of adding these tools later and facing thousands of lines of formatting changes in a single commit.

Detect the ecosystem

Determine the project type from existing files or the scaffolding context:

Signal	Ecosystem
`pyproject.toml` , `setup.py` , `requirements.txt` , `.py` files	Python
`package.json` , `tsconfig.json` , `.ts` / `.js` / `.tsx` files	JavaScript/TypeScript
Both present	Monorepo — configure each ecosystem separately

Also check for existing quality tooling configs (

.eslintrc

,

.prettierrc

,

biome.json

,

[tool.black]

or

[tool.ruff]

in

pyproject.toml

,

.pre-commit-config.yaml

,

lefthook.yml

). If present, preserve them — only migrate to different tools if the user explicitly requests it (see Guardrails).

Set up tooling

After detecting the ecosystem, follow the appropriate guide:

Python projects — see python.md for Ruff + pre-commit setup
JS/TS projects — see javascript.md for Biome + Knip + lefthook + tsc setup

Standard command contract

Every project must expose these five commands (via

package.json

scripts or

Makefile

):

Command	What it does
`format`	Auto-format and sort imports
`lint`	Lint without writing (report only)
`typecheck`	Run type checker ( `tsc --noEmit` , `mypy` , or `pyright` )
`check`	All non-writing checks: lint + typecheck + unused-code detection
`check:fix`	Run autofixers (format + lint fix), then run `check`

Pre-commit hooks should run

check:fix

so that commits are always clean.

Workflow

Install and configure the tools (formatter, linter, type checker)
Add pre-commit hook infrastructure (lefthook or pre-commit)
Run the full suite once to establish a clean baseline
Fix any initial issues so the first "real" commit starts clean
Commit the configuration files as the first or second commit in the project

When working on existing projects

If a project already has code but no quality tooling:

Add and configure the tools
Run the formatter first — commit the formatting changes in a single dedicated commit with a message like
```
chore: apply initial formatting
```
Run the linter — fix issues and commit separately:
```
chore: fix initial lint issues
```
Wire up pre-commit hooks last so all future commits are clean

Guardrails

Don't replace existing mature tooling. If a project already uses ESLint/Prettier, Black, or other established tools, keep them. Only migrate to Biome/Ruff if the user explicitly asks.
Don't broadly disable rules to force a green baseline. Use narrow, targeted exceptions (
```
// biome-ignore
```
,
```
# noqa: XX
```
) with comments explaining why — never bulk-suppress to make errors disappear.
If tooling binaries aren't available, scaffold configs anyway. Write the configuration files and report the install commands the user needs to run.

Completion checklist

Before considering the setup done, verify:

Formatter, linter, and type checker installed and configured for the project's ecosystem
Import sorting enabled (Ruff's
```
I
```
rules or Biome's
```
organizeImports
```
)
All five standard commands work:
```
format
```
,
```
lint
```
,
```
typecheck
```
,
```
check
```
,
```
check:fix
```

Pre-commit hooks configured and executable (

pre-commit run --all-files

or

npx lefthook run pre-commit

)

Baseline autofix applied and a clean check passes with no errors