Lint

Linting Command

This command provides manual control over linting workflows. It can run linters on specific files/directories or discover and document project linters.

Usage Modes

1. Lint Files

Lint one or more files or directories:

/lint path/to/file.py
/lint path/to/directory/
/lint file1.py file2.py file3.py

Behavior:

1. Read ## LINTERS section from project's CLAUDE.md to identify configured linters
2. Run formatters first (auto-fix trivial issues)
3. Run linters second (report substantive issues)
4. If errors found, use linting-root-cause-resolver agent to fix systematically
5. Re-run linters to verify resolution

2. Discover Project Linters

Scan the project and generate the ## LINTERS section for CLAUDE.md:

/lint init
/lint init --force  # Overwrite existing LINTERS section

Behavior:

1. Scan for linting configuration files:
   • .pre-commit-config.yaml
   • pyproject.toml (ruff, mypy, pyright, bandit)
   • package.json (eslint, prettier)
   • .husky/ directory
   • Root .eslintrc*, .prettierrc*, .markdownlint* files
2. Identify configured formatters and linters
3. Generate ## LINTERS section in standard format
4. Append to CLAUDE.md (or update if --force provided)

Implementation

When this command is invoked, perform the following steps based on the arguments:

For /lint <path> (Lint Mode)

1. Read project linting configuration:

   Grep(pattern="^## LINTERS", path="CLAUDE.md", output_mode="content", -A=50)
   

2. If LINTERS section not found:

   • Inform user: "No ## LINTERS section found in CLAUDE.md. Run /lint init first to discover project linters."
   • Exit

3. Parse LINTERS section to identify:

   • Formatters list with file patterns
   • Linters list with file patterns

4. Match file paths to tools:

   • For each provided path, determine which formatters/linters apply based on file extension
   • Example: *.py files → ruff format, ruff check, mypy, pyright

5. Run formatters first (auto-fix phase):

   # Python
   uv run ruff format <file.py>
   
   # JavaScript/TypeScript
   npx prettier --write <file.ts>
   
   # Markdown
   npx markdownlint-cli2 --fix <file.md>
   
   # Shell
   shfmt -w <script.sh>
   

6. Run linters second (validation phase):

   # Python
   uv run ruff check <file.py>
   uv run mypy <file.py>
   uv run pyright <file.py>
   
   # JavaScript/TypeScript
   npx eslint <file.ts>
   
   # Shell
   shellcheck <script.sh>
   

7. If linting errors found:

   • For each file with errors, launch a linting-root-cause-resolver agent:

     Task(subagent_type="linting-root-cause-resolver",
          description="Fix linting errors in <filename>",
          prompt="...")
     

8. Verify resolution:

   • Re-run linters on all files
   • Confirm all issues resolved

For /lint init (Discovery Mode)

1. Check for existing LINTERS section:

   Grep(pattern="^## LINTERS", path="CLAUDE.md", output_mode="content")
   

2. If section exists and --force not provided:

   • Inform user: "## LINTERS section already exists in CLAUDE.md. Use /lint init --force to overwrite."
   • Show existing configuration
   • Exit

3. Scan for git pre-commit hooks:

   test -d .git && echo "Git repository: yes" || echo "Git repository: no"
   test -f .pre-commit-config.yaml && echo "pre-commit config: found" || echo "pre-commit config: not found"
   test -d .husky && echo "husky: found" || echo "husky: not found"
   

4. Scan for Python linting config (pyproject.toml):

   Read(file_path="pyproject.toml")
   

   • Look for [tool.ruff], [tool.mypy], [tool.pyright], [tool.bandit] sections
   • Identify which tools are configured

5. Scan for JavaScript/TypeScript config (package.json):

   Read(file_path="package.json")
   

   • Look for eslint, prettier, @typescript-eslint/* in devDependencies
   • Check for .eslintrc*, .prettierrc* config files

6. Scan for Markdown linting:

   test -f .markdownlint.json && echo "markdownlint config: found"
   test -f .markdownlint.yaml && echo "markdownlint config: found"
   

7. Scan for Shell linting:

   • Look for shellcheck in .pre-commit-config.yaml or installed globally
   • Look for shfmt in .pre-commit-config.yaml or installed globally

8. Generate LINTERS section:

   ## LINTERS
   
   git pre-commit hooks: [enabled|disabled] pre-commit tool: [husky|pre-commit|manual]
   
   ### Formatters
   
   - [tool] [file patterns] ...
   
   ### Static Checking and Linting
   
   - [tool] [file patterns] ...
   

9. Append or update CLAUDE.md:

   • If --force provided, remove existing section first
   • Append generated section to CLAUDE.md
   • Confirm success: "✓ LINTERS section written to CLAUDE.md"

File Pattern Matching

When determining which linters apply to files, use these standard patterns:

• Python: *.py → ruff format, ruff check, mypy, pyright, bandit
• JavaScript/TypeScript: *.{js,ts,jsx,tsx} → prettier, eslint
• Markdown: *.{md,markdown} → markdownlint-cli2
• Shell: *.{sh,bash,zsh,fish} → shfmt, shellcheck
• JSON: *.json → prettier
• YAML: *.{yml,yaml} → prettier (if configured)

Error Handling

If CLAUDE.md doesn't exist:

• In lint mode: Warn and suggest running /lint init
• In init mode: Create CLAUDE.md with LINTERS section

If tools aren't installed:

• Show which tools are missing
• Suggest installation commands (e.g., uv add --dev ruff mypy pyright)

If linting errors persist after agent resolution:

• Show remaining errors
• Ask user if they want to continue investigation or accept current state

Examples

Example 1: Lint a single file

User: /lint src/auth.py

Claude:
1. Reading ## LINTERS section from CLAUDE.md...
2. Found formatters: ruff format [*.py]
3. Found linters: ruff check [*.py], mypy [*.py], pyright [*.py]
4. Running formatter: uv run ruff format src/auth.py
   ✓ Formatted 1 file
5. Running linters:
   - uv run ruff check src/auth.py
     ✗ Found 2 errors (E501, F401)
   - uv run mypy src/auth.py
     ✗ Found 1 error (arg-type)
6. Launching linting-root-cause-resolver agent for src/auth.py...
7. Agent resolved all 3 issues
8. Re-running linters:
   - uv run ruff check src/auth.py ✓
   - uv run mypy src/auth.py ✓
   - uv run pyright src/auth.py ✓
9. All linting errors resolved ✓

Example 2: Lint multiple files

User: /lint src/auth.py src/models.py tests/test_auth.py

Claude:
1. Reading ## LINTERS section from CLAUDE.md...
2. Running formatters on 3 files...
   ✓ All files formatted
3. Running linters on 3 files...
   ✗ src/auth.py: 2 errors
   ✗ src/models.py: 5 errors
   ✓ tests/test_auth.py: no errors
4. Launching concurrent linting-root-cause-resolver agents:
   - Agent 1: Resolving src/auth.py
   - Agent 2: Resolving src/models.py
5. Both agents completed successfully
6. Re-running linters: All files clean ✓

Example 3: Discover project linters

User: /lint init

Claude:
1. Checking for existing ## LINTERS section in CLAUDE.md...
   Not found - proceeding with discovery
2. Scanning project configuration:
   ✓ Git repository detected
   ✓ Found .pre-commit-config.yaml (6 hooks)
   ✓ Found pyproject.toml with [tool.ruff], [tool.mypy], [tool.pyright]
   ✓ Found package.json with prettier, eslint
   ✓ Found .markdownlint.json
3. Generating LINTERS section...

## LINTERS

git pre-commit hooks: enabled
pre-commit tool: pre-commit

### Formatters

- ruff format [*.py]
- prettier [*.{ts,tsx,json,md}]
- markdownlint-cli2 [*.md]

### Static Checking and Linting

- ruff check [*.py]
- mypy [*.py]
- pyright [*.py]
- eslint [*.{ts,tsx}]
- markdownlint-cli2 [*.md]

4. Appended to CLAUDE.md ✓

Example 4: Re-discover linters (force mode)

User: /lint init --force

Claude:
1. Checking for existing ## LINTERS section in CLAUDE.md...
   Found existing section
2. --force flag provided, removing existing section
3. Re-scanning project configuration...
   [Same discovery process as Example 3]
4. Updated CLAUDE.md with new configuration ✓

Notes

• The /lint command respects the holistic-linting skill philosophy: format first (auto-fix trivial issues), lint second (report substantive issues), resolve systematically (understand root causes)
• Orchestrators should launch concurrent linting-root-cause-resolver agents when multiple files have errors
• Sub-agents should use this command on their touched files before completing tasks
• The init mode creates a "cache" in CLAUDE.md to avoid repeated configuration discovery overhead