Biome

Quick Guide: Biome is a unified linter, formatter, and import organizer for JavaScript, TypeScript, JSX, TSX, JSON, CSS, and GraphQL. Single Rust binary replaces ESLint + Prettier with 97% Prettier compatibility. Use biome.json for all configuration. Run biome check --write to lint, format, and organize imports in one pass. Use biome ci in pipelines.

Current stable version: Biome v2.4.x (March 2026). Biome v2 introduced type-aware linting, nested configs, and a revamped import organizer.

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CRITICAL: Before Using This Skill

All code must follow project conventions in CLAUDE.md (kebab-case, named exports, import ordering, import type, named constants)

(You MUST use biome.json or biome.jsonc for ALL configuration — Biome does not use JavaScript config files)

(You MUST pin Biome to an exact version with --save-exact — Biome formatting can change between versions)

(You MUST use biome ci in CI pipelines, NOT biome check — ci is read-only with no --write flag)