linter

name	linter
description	Configure linting, formatting, and editor integration for any stack. Sets up ESLint 9 or Biome for JS/TS, Ruff for Python, golangci-lint for Go, Clippy for Rust, RuboCop for Ruby, or dart analyze for Flutter. Adds Prettier or equivalent formatter, .editorconfig, and VS Code format-on-save. Use when you need to add a linter, fix formatting inconsistencies, migrate from legacy lint tools, or set up code style enforcement.
version	2.0.0
category	productivity
platforms	["CLAUDE_CODE"]

You are in AUTONOMOUS MODE. Do NOT ask questions. Do NOT pause for confirmation. Execute every phase below in sequence, making decisions based on what you find.

============================================================ PHASE 0 — INPUT

$ARGUMENTS may contain:

• --tool=TOOL — force a specific linter: eslint, biome, ruff, golangci-lint, rubocop, clippy
• --fix — auto-fix all fixable violations after setup (default: setup only)
• --strict — enable stricter rule sets (recommended for new projects)
• --no-format — skip formatter setup, configure linter only
• --migrate — migrate from one tool to another (e.g., ESLint → Biome, flake8 → Ruff)

If no arguments, auto-detect the stack and set up the appropriate tools.

============================================================ PHASE 1 — STACK DETECTION

Detect the language and existing lint/format tooling:

JavaScript / TypeScript:

• Existing: .eslintrc.*, eslint.config.* (flat config), biome.json, biome.jsonc
• Formatter: .prettierrc*, .prettierignore, biome.json
• Framework: React (jsx), Vue (.vue), Svelte (.svelte), Angular
• TypeScript: tsconfig.json present → enable type-aware lint rules

Python:

• Existing: ruff.toml, pyproject.toml [tool.ruff], .flake8, setup.cfg [flake8], pylintrc
• Formatter: pyproject.toml [tool.black], ruff.toml [format]
• Type checker: mypy.ini, pyproject.toml [tool.mypy], pyrightconfig.json

Go:

• Existing: .golangci.yml, .golangci.yaml
• Formatter: gofmt / goimports (built-in)

Rust:

• Existing: clippy.toml, .clippy.toml
• Formatter: rustfmt.toml, .rustfmt.toml

Ruby:

• Existing: .rubocop.yml
• Formatter: same tool (RuboCop handles both)

Flutter / Dart:

• Existing: analysis_options.yaml
• Formatter: dart format (built-in)

Record: language, existing tools, missing tools, framework-specific needs.

============================================================ PHASE 2 — CONFIGURE LINTER

2.1 — JavaScript / TypeScript:

If no linter exists OR --migrate from legacy ESLint:

Prefer ESLint 9 flat config for new setups:

1. Install:

   npm install --save-dev eslint @eslint/js typescript-eslint globals
   

   Add framework plugins:
   • React: eslint-plugin-react, eslint-plugin-react-hooks
   • Next.js: @next/eslint-plugin-next
   • Vue: eslint-plugin-vue
2. Create eslint.config.js:

   import js from '@eslint/js';
   import tseslint from 'typescript-eslint';
   import globals from 'globals';
   
   export default tseslint.config(
     js.configs.recommended,
     ...tseslint.configs.recommended,
     {
       languageOptions: {
         globals: { ...globals.node }
       },
       rules: {
         '@typescript-eslint/no-unused-vars': ['error', { argsIgnorePattern: '^_' }],
         '@typescript-eslint/no-explicit-any': 'warn',
       }
     },
     { ignores: ['dist/', 'node_modules/', 'coverage/'] }
   );
   

3. Add lint script to package.json: "lint": "eslint ."

If Biome is preferred or requested:

1. Install: npm install --save-dev --exact @biomejs/biome
2. Create biome.json:

   {
     "$schema": "https://biomejs.dev/schemas/1.9.0/schema.json",
     "organizeImports": { "enabled": true },
     "linter": {
       "enabled": true,
       "rules": { "recommended": true }
     },
     "formatter": {
       "enabled": true,
       "indentStyle": "space",
       "indentWidth": 2
     }
   }
   

3. Add scripts: "lint": "biome check .", "lint:fix": "biome check --write ."

If --strict: enable tseslint.configs.strictTypeChecked or Biome "all" rules with selected disables.

2.2 — Python:

Prefer Ruff (replaces flake8, isort, black, pyflakes, pycodestyle):

1. Add to pyproject.toml:

   [tool.ruff]
   target-version = "py312"
   line-length = 88
   
   [tool.ruff.lint]
   select = ["E", "F", "W", "I", "N", "UP", "B", "A", "SIM", "TCH"]
   ignore = []
   
   [tool.ruff.format]
   quote-style = "double"
   

   If --strict: add "S" (bandit security), "D" (docstrings), "ANN" (type annotations).

If migrating from flake8/pylint/isort:

• Read existing config, map rules to Ruff equivalents
• Remove old tool configs and dependencies

2.3 — Go:

Configure golangci-lint:

1. Create .golangci.yml:

   linters:
     enable:
       - errcheck
       - gosimple
       - govet
       - ineffassign
       - staticcheck
       - unused
       - gocritic
       - gofumpt
       - misspell
       - revive
   linters-settings:
     gocritic:
       enabled-tags: [diagnostic, style, performance]
     gofumpt:
       extra-rules: true
   issues:
     max-issues-per-linter: 0
     max-same-issues: 0
   

   If --strict: add exhaustive, nilnil, wrapcheck, errorlint.

2.4 — Rust:

Clippy is built-in. Create clippy.toml for custom config if needed:

cognitive-complexity-threshold = 25

Add to CI: cargo clippy -- -D warnings

Create rustfmt.toml:

edition = "2021"
max_width = 100
use_field_init_shorthand = true

2.5 — Ruby:

Configure RuboCop:

1. Install: gem install rubocop (or add to Gemfile)
2. Create .rubocop.yml with project-appropriate rules

2.6 — Flutter / Dart:

Configure or update analysis_options.yaml:

include: package:flutter_lints/flutter.yaml
linter:
  rules:
    prefer_const_constructors: true
    prefer_const_declarations: true
    avoid_print: true
    prefer_single_quotes: true

============================================================ PHASE 3 — CONFIGURE FORMATTER

Skip if --no-format.

JavaScript / TypeScript (if not using Biome):

1. Install: npm install --save-dev prettier
2. Create .prettierrc:

   {
     "semi": true,
     "singleQuote": true,
     "trailingComma": "all",
     "printWidth": 100,
     "tabWidth": 2
   }
   

3. Create .prettierignore:

   dist
   node_modules
   coverage
   pnpm-lock.yaml
   

4. Add script: "format": "prettier --write .", "format:check": "prettier --check ."

Python (if not using Ruff format):

• Black is included if Ruff is not used
• Ruff format handles formatting when Ruff is the linter

Go: gofmt / goimports — no config needed, built into Go toolchain.

Rust: rustfmt — configured via rustfmt.toml in Phase 2.

Create .editorconfig if it does not exist:

root = true

[*]
indent_style = space
indent_size = 2
end_of_line = lf
charset = utf-8
trim_trailing_whitespace = true
insert_final_newline = true

[*.{py,rs}]
indent_size = 4

[*.go]
indent_style = tab

[Makefile]
indent_style = tab

============================================================ PHASE 4 — EDITOR INTEGRATION

Create or update .vscode/settings.json (merge with existing):

{
  "editor.formatOnSave": true,
  "editor.codeActionsOnSave": {
    "source.fixAll": "explicit",
    "source.organizeImports": "explicit"
  }
}

Add language-specific settings:

• ESLint: "editor.defaultFormatter": "dbaeumer.vscode-eslint" for JS/TS files
• Biome: "editor.defaultFormatter": "biomejs.biome" for JS/TS files
• Prettier: "editor.defaultFormatter": "esbenp.prettier-vscode" for JS/TS/JSON/MD
• Ruff: "[python]": { "editor.defaultFormatter": "charliermarsh.ruff" }
• Go: "[go]": { "editor.defaultFormatter": "golang.go" }
• Rust: "[rust]": { "editor.defaultFormatter": "rust-lang.rust-analyzer" }

Create or update .vscode/extensions.json with recommended extensions:

{
  "recommendations": [
    "dbaeumer.vscode-eslint",
    "esbenp.prettier-vscode",
    "EditorConfig.EditorConfig"
  ]
}

============================================================ PHASE 5 — FIX EXISTING VIOLATIONS

If --fix was passed:

1. Run the auto-fixer:

   • ESLint: npx eslint . --fix
   • Biome: npx biome check --write .
   • Prettier: npx prettier --write .
   • Ruff: ruff check --fix . && ruff format .
   • golangci-lint: golangci-lint run --fix
   • Clippy: cargo clippy --fix --allow-dirty
   • dart: dart fix --apply && dart format .

2. Count remaining (non-auto-fixable) violations:

   • Run lint again without --fix
   • Report count by rule/category

3. Commit auto-fixes: style: auto-fix lint and format violations

If --fix was NOT passed, still report the violation count so the user knows the current state.

============================================================ SELF-HEALING VALIDATION (max 2 iterations)

After completing, validate the output was produced correctly:

1. Verify generated files exist and are syntactically valid.
2. Run any available validation (lint, type-check, dry-run).
3. If the skill produces configuration, verify it parses without errors.

IF VALIDATION FAILS:

• Diagnose from error context and re-generate the failing artifact
• Repeat up to 2 iterations

============================================================ OUTPUT

Print a summary:

## Linter Setup Complete

### Stack: {language} / {framework}

### Tools Configured
- Linter: {ESLint 9 | Biome | Ruff | golangci-lint | Clippy | RuboCop}
- Formatter: {Prettier | Biome | Ruff | gofmt | rustfmt}
- Editor: VS Code format-on-save enabled

### Current State
- Auto-fixable violations: {N} (fixed with --fix)
- Remaining violations: {N} (require manual review)
- Clean files: {N}/{total}

### Files Created/Modified
- {list of files}

============================================================ NEXT STEPS

1. Run /git-hooks to enforce lint on every commit
2. Run the linter to see remaining violations: npm run lint / ruff check .
3. Add lint step to CI: run /github-actions to generate CI workflow
4. Review and adjust rule severity in the config file as needed

============================================================ SELF-EVOLUTION TELEMETRY

After producing output, record execution metadata for the /evolve pipeline.

Check if a project memory directory exists:

• Look for the project path in ~/.claude/projects/
• If found, append to skill-telemetry.md in that memory directory

Entry format:

### /linter — {{YYYY-MM-DD}}
- Outcome: {{SUCCESS | PARTIAL | FAILED}}
- Self-healed: {{yes — what was healed | no}}
- Iterations used: {{N}} / {{N max}}
- Bottleneck: {{phase that struggled or "none"}}
- Suggestion: {{one-line improvement idea for /evolve, or "none"}}

Only log if the memory directory exists. Skip silently if not found. Keep entries concise — /evolve will parse these for skill improvement signals.

============================================================ DO NOT

• Do NOT install both ESLint and Biome — they serve the same purpose, pick one
• Do NOT install both Prettier and Biome — Biome includes formatting
• Do NOT install deprecated tools (TSLint, flake8 for new projects, prettier-eslint)
• Do NOT use ESLint legacy config format (.eslintrc.json) for new setups — use flat config (eslint.config.js)
• Do NOT enable every available rule — start with recommended and add incrementally
• Do NOT auto-fix violations that change semantics (e.g., no-unused-vars removing code)
• Do NOT modify files outside the project root
• Do NOT overwrite existing lint configs without reading them first and preserving custom rules
• Do NOT configure formatters with conflicting settings (e.g., Prettier tabs + EditorConfig spaces)