Biome Validator

Validates Biome 2.3+ configuration and prevents outdated patterns. Ensures type-aware linting, domains, and modern Biome features are properly configured.

When This Activates

• Setting up linting for a new project

• Before any code quality work

• Auditing existing Biome configurations

• After AI generates biome.json

• CI/CD pipeline validation

Quick Start

python3 ~/.claude/skills/biome-validator/scripts/validate.py --root . python3 ~/.claude/skills/biome-validator/scripts/validate.py --root . --strict

What Gets Checked

1. Biome Version & Schema

GOOD - Biome 2.3+:

{ "$schema": "https://biomejs.dev/schemas/2.3.11/schema.json" }

BAD - Old schema:

{ "$schema": "https://biomejs.dev/schemas/1.9.0/schema.json" }

2. Package Version

// GOOD: v2.3+ "@biomejs/biome": "^2.3.0"

// BAD: v1.x or v2.0-2.2 "@biomejs/biome": "^1.9.0"

3. Linter Configuration

GOOD - Biome 2.x:

{ "linter": { "enabled": true, "rules": { "recommended": true, "suspicious": { "noExplicitAny": "warn" } } } }

4. Biome Assist (2.0+)

GOOD - Using assist:

{ "assist": { "actions": { "source": { "organizeImports": "on" } } } }

BAD - Old organizeImports location:

{ "organizeImports": { "enabled": true } }

5. Domains (2.0+)

GOOD - Using domains for framework-specific rules:

{ "linter": { "domains": { "react": "on", "next": "on" } } }

6. Suppression Comments

GOOD - Biome 2.0+ comments:

// biome-ignore lint/suspicious/noExplicitAny: legacy code // biome-ignore-all lint/style/useConst // biome-ignore-start lint/complexity // biome-ignore-end

BAD - Wrong format:

// @ts-ignore // Not Biome // eslint-disable // Wrong tool

Biome 2.3+ Features

Type-Aware Linting

Biome 2.0+ includes type inference without requiring TypeScript compiler:

{ "linter": { "rules": { "correctness": { "noUndeclaredVariables": "error", "useAwaitThenable": "error" } } } }

Assist Actions

{ "assist": { "actions": { "source": { "organizeImports": "on", "useSortedKeys": "on" } } } }

Multi-file Analysis

Lint rules can query information from other files for more powerful analysis.

Framework Domains

{ "linter": { "domains": { "react": "on", // React-specific rules "next": "on", // Next.js rules "test": "on" // Testing framework rules } } }

Recommended Configuration

{ "$schema": "https://biomejs.dev/schemas/2.3.11/schema.json", "assist": { "actions": { "source": { "organizeImports": "on" } } }, "linter": { "enabled": true, "rules": { "recommended": true, "complexity": { "noForEach": "off" }, "style": { "noNonNullAssertion": "off" }, "suspicious": { "noArrayIndexKey": "off", "noExplicitAny": "warn" }, "correctness": { "useAwaitThenable": "error", "noLeakedRender": "error" } }, "domains": { "react": "on", "next": "on" } }, "formatter": { "enabled": true, "indentStyle": "space", "indentWidth": 2, "lineWidth": 100 }, "javascript": { "formatter": { "quoteStyle": "single", "trailingCommas": "es5", "semicolons": "always" } }, "files": { "ignore": [ "node_modules", "dist", "build", ".next", "out", ".cache", ".turbo", "coverage" ] } }

Deprecated Patterns

Deprecated Replacement (2.3+)

organizeImports.enabled

assist.actions.source.organizeImports

Schema < 2.0 Schema 2.3.11+

@biomejs/biome < 2.3 @biomejs/biome@latest

No domains config Use linter.domains for frameworks

Validation Output

=== Biome 2.3+ Validation Report ===

Package Version: @biomejs/biome@2.3.11 ✓

Configuration: ✓ Schema version: 2.3.11 ✓ Linter enabled with recommended rules ✓ Using assist.actions for imports ✗ No domains configured (consider enabling react, next) ✓ Formatter configured

Rules: ✓ noExplicitAny: warn ✓ useAwaitThenable: error ✗ noLeakedRender not enabled (recommended)

Summary: 2 issues found

Migration from ESLint

Step 1: Install Biome

bun remove eslint prettier eslint-config-* eslint-plugin-* bun add -D @biomejs/biome@latest

Step 2: Create biome.json

bunx biome init

Step 3: Migrate rules

bunx biome migrate eslint --write

Step 4: Update scripts

{ "scripts": { "lint": "biome lint .", "lint:fix": "biome lint --write .", "format": "biome format --write .", "check": "biome check .", "check:fix": "biome check --write ." } }

Step 5: Remove old configs

rm .eslintrc* .prettierrc* .eslintignore .prettierignore

VS Code Integration

// .vscode/settings.json { "editor.formatOnSave": true, "editor.defaultFormatter": "biomejs.biome", "editor.codeActionsOnSave": { "source.organizeImports.biome": "explicit", "quickfix.biome": "explicit" } }

CI/CD Integration

.github/workflows/lint.yml

• name: Validate Biome Config run: | python3 ~/.claude/skills/biome-validator/scripts/validate.py
  --root .
  --strict
  --ci

• name: Lint run: bunx biome check --error-on-warnings .

Integration

• linter-formatter-init

• Sets up Biome from scratch

• nextjs-validator

• Validates Next.js (enable next domain)

• bun-validator

• Validates Bun workspace