Configure Linting

/configure:linting

Check and configure linting tools against modern best practices.

When to Use This Skill

Context

• Project root: !pwd
• Biome config: !find . -maxdepth 1 -name 'biome.json' -o -name 'biome.jsonc'
• Ruff config: !grep -l 'tool.ruff' pyproject.toml
• Clippy config: !grep -l 'lints.clippy' Cargo.toml
• Legacy linters: !find . -maxdepth 1 \( -name '.eslintrc*' -o -name '.flake8' -o -name '.pylintrc' \)
• Package files: !find . -maxdepth 1 \( -name 'package.json' -o -name 'pyproject.toml' -o -name 'Cargo.toml' \)
• Pre-commit config: !find . -maxdepth 1 -name '.pre-commit-config.yaml'
• CI workflows: !find .github/workflows -maxdepth 1 -name '*.yml'

Parameters

Parse from $ARGUMENTS:

• --check-only: Report linting compliance status without modifications
• --fix: Apply all fixes automatically without prompting
• --linter <biome|ruff|clippy>: Override auto-detection and force specific linter

Modern linting preferences:

• JavaScript/TypeScript: Biome (unified linter + formatter, fast)
• Python: Ruff (replaces flake8, isort, pyupgrade)
• Rust: Clippy with workspace lints

Execution

Execute this linting configuration check:

Step 1: Detect project language and existing linters

Read the context values above and determine:

If --linter flag is set, use that linter regardless of detection.

Step 2: Verify latest tool versions

Use WebSearch or WebFetch to check current versions:

1. Biome: Check biomejs.dev or GitHub releases 2. Ruff: Check docs.astral.sh/ruff or GitHub releases 3. Clippy: Check Rust releases

Step 3: Analyze current linter configuration

For each detected linter, check configuration completeness:

Biome (for JS/TS):

• Config file exists with linter rules
• Formatter configured
• File patterns and ignores set
• Recommended rules enabled

Ruff (for Python):

• pyproject.toml has [tool.ruff] section
• Rules selected (E, F, I, N, etc.)
• Line length and target Python version set

Clippy:

• Cargo.toml has [lints.clippy] section
• Pedantic lints enabled
• Workspace-level lints if applicable

Step 4: Generate compliance report

Print a compliance report covering:

• Config file status (exists / missing)
• Linter enabled status
• Rules configuration (recommended / minimal / missing)
• Formatter integration
• Ignore patterns
• Lint scripts in package.json / Makefile
• Pre-commit hook integration
• CI/CD check integration

End with overall issue count and recommendations.

If --check-only is set, stop here.

Step 5: Configure linting (if --fix or user confirms)

Apply configuration using templates from REFERENCE.md.

For Biome (JS/TS): 1. Install Biome as dev dependency 2. Create biome.json with recommended rules 3. Add npm scripts (lint, lint:fix, format, check)

For Ruff (Python): 1. Install Ruff via uv add --group dev ruff 2. Add [tool.ruff] section to pyproject.toml 3. Configure rules, line length, target version

For Clippy (Rust): 1. Add [lints.clippy] section to Cargo.toml 2. Enable pedantic lints 3. Configure workspace-level lints if applicable

If legacy linters are detected (ESLint, Flake8, etc.), offer migration. See migration guides in REFERENCE.md.

Step 6: Configure pre-commit and CI integration

1. Add linter pre-commit hook to .pre-commit-config.yaml 2. Add linter CI check to GitHub Actions workflow 3. Use templates from REFERENCE.md

Step 7: Update standards tracking

Update .project-standards.yaml:

components:
  linting: "2025.1"
  linting_tool: "[biome|ruff|clippy]"
  linting_pre_commit: true
  linting_ci: true

Step 8: Print final compliance report

Print a summary of all changes applied, scripts added, integrations configured, and next steps for the user.

For detailed configuration templates, migration guides, and CI integration patterns, see REFERENCE.md.

Agentic Optimizations

Flags

Examples

# Check compliance and offer fixes
/configure:linting

# Check only, no modifications
/configure:linting --check-only

# Auto-fix and migrate to Biome
/configure:linting --fix --linter biome

Error Handling

• Multiple linters detected: Warn about conflict, suggest migration
• No package manager found: Cannot install linter, error
• Invalid configuration: Report parse error, offer to replace with template
• Missing dependencies: Offer to install required packages

See Also

• /configure:formatting - Configure code formatting
• /configure:pre-commit - Pre-commit hook configuration
• /configure:all - Run all compliance checks
• Biome documentation: https://biomejs.dev
• Ruff documentation: https://docs.astral.sh/ruff
• Clippy documentation: https://doc.rust-lang.org/clippy

Linting Configuration Reference

Detailed configuration templates, migration guides, and integration patterns for linting tools.

Biome Configuration (JavaScript/TypeScript)

Installation

npm install --save-dev @biomejs/biome
# or
bun add --dev @biomejs/biome

biome.json Template

{
  "$schema": "https://biomejs.dev/schemas/1.9.4/schema.json",
  "vcs": {
    "enabled": true,
    "clientKind": "git",
    "useIgnoreFile": true
  },
  "files": {
    "include": ["src/**/*.ts", "src/**/*.tsx", "src/**/*.js", "src/**/*.jsx"],
    "ignore": [
      "node_modules",
      "dist",
      "build",
      ".next",
      "coverage",
      "*.config.js",
      "*.config.ts"
    ]
  },
  "formatter": {
    "enabled": true,
    "formatWithErrors": false,
    "indentStyle": "space",
    "indentWidth": 2,
    "lineWidth": 100
  },
  "linter": {
    "enabled": true,
    "rules": {
      "recommended": true,
      "suspicious": {
        "noExplicitAny": "warn",
        "noConsoleLog": "warn"
      },
      "complexity": {
        "noExcessiveCognitiveComplexity": "warn",
        "noForEach": "off"
      },
      "style": {
        "useConst": "error",
        "useTemplate": "warn"
      },
      "correctness": {
        "noUnusedVariables": "error"
      }
    }
  },
  "organizeImports": {
    "enabled": true
  },
  "javascript": {
    "formatter": {
      "quoteStyle": "single",
      "semicolons": "always",
      "trailingCommas": "all",
      "arrowParentheses": "always"
    }
  },
  "json": {
    "formatter": {
      "enabled": true
    }
  }
}

npm Scripts

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

Ruff Configuration (Python)

Installation

uv add --group dev ruff

pyproject.toml Template

[tool.ruff]
# Target Python version
target-version = "py312"

# Line length
line-length = 100

# Exclude directories
exclude = [
    ".git",
    ".venv",
    "__pycache__",
    "dist",
    "build",
    "*.egg-info",
]

[tool.ruff.lint]
# Rule selection
select = [
    "E",      # pycodestyle errors
    "F",      # pyflakes
    "I",      # isort
    "N",      # pep8-naming
    "UP",     # pyupgrade
    "B",      # flake8-bugbear
    "C4",     # flake8-comprehensions
    "SIM",    # flake8-simplify
    "TCH",    # flake8-type-checking
    "PTH",    # flake8-use-pathlib
    "RUF",    # Ruff-specific rules
]

# Rules to ignore
ignore = [
    "E501",   # Line too long (handled by formatter)
    "B008",   # Function call in default argument
]

# Per-file ignores
[tool.ruff.lint.per-file-ignores]
"__init__.py" = ["F401"]  # Unused imports
"tests/**/*.py" = ["S101"]  # Use of assert

[tool.ruff.lint.isort]
known-first-party = ["your_package"]
force-sort-within-sections = true

[tool.ruff.lint.mccabe]
max-complexity = 10

[tool.ruff.format]
# Formatter options
quote-style = "double"
indent-style = "space"
line-ending = "auto"

Clippy Configuration (Rust)

Cargo.toml Template

[lints.clippy]
# Enable pedantic lints
pedantic = { level = "warn", priority = -1 }

# Specific lints to deny
all = "warn"
correctness = "deny"
suspicious = "deny"
complexity = "warn"
perf = "warn"
style = "warn"

# Allow some pedantic lints that are too noisy
module-name-repetitions = "allow"
missing-errors-doc = "allow"
missing-panics-doc = "allow"

# Deny specific dangerous patterns
unwrap-used = "deny"
expect-used = "deny"
panic = "deny"

[lints.rust]
unsafe-code = "deny"
missing-docs = "warn"

Workspace Configuration

[workspace.lints.clippy]
pedantic = { level = "warn", priority = -1 }
all = "warn"

[workspace.lints.rust]
unsafe-code = "deny"

Run Command

cargo clippy --all-targets --all-features -- -D warnings

Migration Guides

Flake8/isort/black to Ruff

1. Install Ruff: uv add --group dev ruff 2. Configure in pyproject.toml (see Ruff template above) 3. Remove old tools: uv remove flake8 isort black pyupgrade 4. Remove old config files: rm .flake8 .isort.cfg 5. Update pre-commit hooks (see below)

ESLint to Biome

1. Install Biome: bun add --dev @biomejs/biome 2. Create biome.json (see template above) 3. Remove ESLint: bun remove eslint @typescript-eslint/parser @typescript-eslint/eslint-plugin 4. Remove config files: rm .eslintrc* .eslintignore 5. Update npm scripts and pre-commit hooks

Pre-commit Integration

Biome

repos:
  - repo: https://github.com/biomejs/pre-commit
    rev: v2.4.16
    hooks:
      - id: biome-check
        additional_dependencies: ["@biomejs/biome@2.4.16"]

Ruff

repos:
  - repo: https://github.com/astral-sh/ruff-pre-commit
    rev: v0.15.15
    hooks:
      - id: ruff
        args: [--fix]
      - id: ruff-format

Clippy

repos:
  - repo: local
    hooks:
      - id: clippy
        name: clippy
        entry: cargo clippy --all-targets --all-features -- -D warnings
        language: system
        types: [rust]
        pass_filenames: false

CI/CD Integration

GitHub Actions - Biome

- name: Run Biome
  run: npx @biomejs/biome ci .

GitHub Actions - Ruff

- name: Run Ruff
  run: |
    uv run ruff check .
    uv run ruff format --check .

GitHub Actions - Clippy

- name: Run Clippy
  run: cargo clippy --all-targets --all-features -- -D warnings

Compliance Report Template

Linting Configuration Compliance Report
========================================
Project: [name]
Language: [TypeScript | Python | Rust]
Linter: [Biome 1.x | Ruff 0.x | Clippy 1.x]

Configuration:
  Config file             biome.json                 [EXISTS | MISSING]
  Linter enabled          true                       [ENABLED | DISABLED]
  Rules configured        recommended + custom       [CONFIGURED | MINIMAL]
  Formatter integrated    biome format               [CONFIGURED | SEPARATE]
  Ignore patterns         node_modules, dist         [CONFIGURED | INCOMPLETE]

Rules:
  Recommended             enabled                    [ENABLED | DISABLED]
  Suspicious              enabled                    [ENABLED | DISABLED]
  Complexity              enabled                    [ENABLED | DISABLED]
  Performance             enabled                    [ENABLED | N/A]
  Style                   enabled                    [ENABLED | N/A]

Scripts:
  lint command            package.json scripts       [CONFIGURED | MISSING]
  lint:fix                package.json scripts       [CONFIGURED | MISSING]

Integration:
  Pre-commit hook         .pre-commit-config.yaml    [CONFIGURED | MISSING]
  CI/CD check             .github/workflows/         [CONFIGURED | MISSING]

Overall: [X issues found]