# Setup Biome

> Install Biome linter with Ultracite preset, create biome.jsonc config, and configure Claude Code Stop hook for auto-fix before finishing. Use when setting up linting, formatting, Biome, Ultracite, or code quality enforcement.

- Skill: `redpanda-data/setup-biome` (Agent Skill, multi-file: 4 files)
- Install (CLI): `npx skillmds@latest add redpanda-data/setup-biome`
- Raw SKILL.md: https://api.skillmd.com/api/skills/redpanda-data/setup-biome/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: redpanda-data (https://skillmd.com/u/redpanda-data)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/redpanda-data/setup-biome

---


# Setup Biome + Ultracite

- **Biome** linter/formatter + **Ultracite** opinionated preset
- Stop hook auto-fix lint/format on changed JS/TS files (skip `noUnusedImports`, avoid deletion loops)
- Strict: `noConsole`, cognitive complexity 15, `noDeprecatedImports`, restricted imports (moment/lodash/classnames/mobx/yup)

## Steps

### 1. Install
```bash
bun add -D @biomejs/biome ultracite --yarn
```

### 2. Create `biome.jsonc`
From [REFERENCE.md](REFERENCE.md). Extend `ultracite/biome/core` + `ultracite/biome/react`. VCS git on. Test files re-enable `noExplicitAny`.

### 3. Package.json scripts
```json
{
  "scripts": {
    "lint": "biome check .",
    "lint:fix": "biome check --write .",
    "lint:file": "biome check",
    "lint:fix:file": "biome check --write"
  }
}
```

### 4. Hook
Copy `scripts/biome-autofix.sh` -> `.claude/hooks/`. `chmod +x`. Add to Stop.

### 5. Verify
- [ ] `bun run lint` + `bun run lint:fix` work
- [ ] Hook executable + configured