biome — SKILL.md

Variant: standard · When to use: linting and formatting a JS/TS project with Biome v2.

Overview

Biome is a single Rust binary that lints, formats, and organizes imports for JavaScript, TypeScript, JSX, JSON, CSS, and GraphQL — one tool and one biome.json in place of the ESLint + Prettier stack. It is the JS/TS analog of Python's ruff: fast, opinionated defaults, one config. This skill covers installing Biome (v2), writing biome.json, the current CLI (including the biome ci gate), migrating an existing ESLint/Prettier setup, the v1→v2 changes that trip up stale knowledge, and authoring custom lint rules as GritQL plugins. Verified against Biome v2; confirm the exact current version when you install.

When to activate

• ✅ Adding lint + format to a JS/TS project (new or replacing ESLint/Prettier).
• ✅ Writing or fixing a biome.json (formatter, linter rules, import organizing, VCS, overrides).
• ✅ Wiring a lint/format CI gate.
• ✅ Migrating from ESLint/Prettier, or authoring a custom rule as a GritQL plugin.

Do NOT activate when:

• You need to wire Biome as a task in a Turborepo/pnpm pipeline — compose with the turborepo skill; this skill owns Biome itself, not the task graph.
• The project is Python — that's ruff (Biome is the JS/TS counterpart, named here only as the analog).