Lint Code

lint-code

Run code linters based on project configuration. Uses centralized detection to determine and run the appropriate linter.

Usage

/lint-code                    # Lint entire project
/lint-code src/utils.ts       # Lint specific file
/lint-code --fix              # Auto-fix issues
/lint-code src/ --fix         # Lint directory with auto-fix

Lints the entire project by default. You can also specify:

• A file path to lint a specific file
• --fix to auto-fix issues where possible

Instructions

Step 1: Discover Project Context

Use the Explore agent to discover project context:

Explore Prompt:

Discover project context for linting code. Find and read:

1. Root CLAUDE.md - Read CLAUDE.md at project root. All instructions are MANDATORY.
2. Relevant CLAUDE.md Files - Search **/CLAUDE.md for keywords: lint, eslint, prettier, ruff, format, style, conventions
3. Project Type - Detect from package.json, pyproject.toml, go.mod, Cargo.toml, etc.

Return: Project type, linter(s), lint command, code style instructions

From the Explore results, extract:

• Project type and package manager
• Linter(s) configured
• Lint command
• Any code style instructions from CLAUDE.md

Step 2: Run Linter

Using the detected linter, run the appropriate command:

JavaScript/TypeScript:

# ESLint
npx eslint .
npx eslint . --fix  # with auto-fix

# Prettier (check)
npx prettier --check .
npx prettier --write .  # with auto-fix

# Biome
npx biome check .
npx biome check --apply .  # with auto-fix

Python:

# Ruff (fast, recommended)
ruff check .
ruff check . --fix  # with auto-fix
ruff format .  # formatting

# Flake8
flake8 .

# Black (formatting)
black --check .
black .  # with auto-fix

Go:

# golangci-lint
golangci-lint run

# go fmt
go fmt ./...

# go vet
go vet ./...

Rust:

# Clippy
cargo clippy

# rustfmt
cargo fmt --check
cargo fmt  # with auto-fix

Ruby:

# RuboCop
bundle exec rubocop
bundle exec rubocop -a  # with auto-fix

Java:

# Checkstyle (via Maven)
mvn checkstyle:check

# Checkstyle (via Gradle)
./gradlew checkstyleMain

# SpotBugs
mvn spotbugs:check
./gradlew spotbugsMain

C#/.NET:

# dotnet format
dotnet format --verify-no-changes
dotnet format  # with auto-fix

# With analyzers
dotnet build /p:TreatWarningsAsErrors=true

Step 3: Parse Results

Extract from linter output:

• Total issues found
• Errors vs warnings
• File locations
• Rule violations

Step 4: Report Results

Output in this format (see below).

Step 5 (Final): Evaluate Reusable Patterns

Run the pattern-evaluator agent to assess whether any reusable patterns (rules, skills, or agents) were discovered during this session and should be persisted.

Report Format

Output in this format:

## Lint Results

**Linter**: [detected linter]
**Command**: [command executed]
**Status**: PASSED / [X] issues found

## Summary

- Errors: X
- Warnings: Y
- Fixable: Z

## Issues

### Errors

| File | Line | Rule | Message |
|------|------|------|---------|
| src/index.ts | 10 | no-unused-vars | 'x' is defined but never used |

### Warnings

| File | Line | Rule | Message |
|------|------|------|---------|
| src/utils.ts | 25 | prefer-const | Use 'const' instead of 'let' |

## Auto-fixable Issues

Run `[command] --fix` to automatically fix [Z] issues.

## Manual Fixes Required

### [File:Line] - [Rule]
**Issue**: [description]
**Fix**: [suggested fix]

Common Linter Configurations

ESLint + Prettier (Node.js)

// .eslintrc.json
{
  "extends": ["eslint:recommended", "prettier"],
  "env": { "node": true, "es2022": true }
}

Ruff (Python)

# pyproject.toml
[tool.ruff]
select = ["E", "F", "I", "N", "W"]
ignore = ["E501"]

golangci-lint (Go)

# .golangci.yml
linters:
  enable:
    - gofmt
    - govet
    - errcheck
    - staticcheck

Linter Priority

When multiple linters are configured, use this order:

JavaScript/TypeScript:

1. package.json scripts.lint → use that command
2. Biome (if biome.json exists)
3. ESLint (if .eslintrc* exists)
4. Prettier (formatting only, if .prettierrc* exists)

Python:

1. pyproject.toml configured tool → use that
2. Ruff (preferred - fast, modern)
3. Flake8 + Black (legacy setup)

If multiple linters configured: Run in order: static analysis first, then formatting. Example: ESLint → Prettier, or Ruff check → Ruff format

Error Handling

No Linter Configured

If no linter configuration is found:

No linter configured for this project.

Question: "Would you like to set up a linter?"
Options:
  - Show recommended linter for [detected language]
  - Continue without linting
  - Cancel

Recommendations by language:

• Node.js → ESLint + Prettier
• Python → Ruff
• Go → golangci-lint
• Rust → Clippy (built-in)
• Ruby → RuboCop
• Java → Checkstyle
• C#/.NET → dotnet format

Linter Not Installed

If the linter command fails with "command not found":

Linter '[name]' is not installed.

Question: "How should I proceed?"
Options:
  - Show installation instructions
  - Try a different linter
  - Cancel

Installation commands:

• ESLint: npm install -D eslint
• Prettier: npm install -D prettier
• Ruff: pip install ruff
• golangci-lint: go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest
• RuboCop: gem install rubocop

Invalid Configuration

If linter fails due to config errors:

## Configuration Error

Linter '[name]' failed due to invalid configuration.

Error: [error message]
Config file: [path to config]

Fix the configuration, then run `/lint-code` again.

Exit Code Handling

Timeout on Large Codebase

If linting takes longer than 60 seconds:

Warning: Linting is taking a long time on this codebase.

Question: "How should I proceed?"
Options:
  - Continue waiting
  - Lint specific directory instead
  - Cancel

Tips

• Run linters in CI to catch issues early
• Use --fix carefully; review changes before committing
• Configure your editor to lint on save
• Add pre-commit hooks for automatic linting