Code Linting Skill

Purpose

Automated code quality and style checking for code reviews. This Skill runs appropriate linters based on project language and provides structured quality reports.

What It Does

• Detects project language
• Runs language-appropriate linter
• Reports style violations and anti-patterns
• Checks best practice compliance
• Identifies code smells

---

Supported Languages

Python

• Tool: ruff (modern, fast) or pylint (comprehensive)
• Checks: PEP 8 style, code complexity, common mistakes
• Speed: Very fast (ruff < 1s, pylint 3-5s)

JavaScript/TypeScript

• Tool: eslint
• Checks: Code style, potential bugs, best practices
• Speed: Fast (2-5s)

Go

• Tool: golangci-lint
• Checks: Multiple linters (gofmt, govet, staticcheck, etc.)
• Speed: Moderate (5-10s)

Ruby

• Tool: rubocop
• Checks: Ruby style guide, best practices
• Speed: Moderate (5-10s)

Java

• Tool: Checkstyle (style) + PMD (code quality)
• Checks: Code style, complexity, best practices, bug patterns
• Speed: Moderate (10-15s)
• Integration: Via Maven/Gradle plugins

---

Output Format

Results are saved to coordination/lint_results.json:

{
  "timestamp": "2025-11-07T20:00:00Z",
  "language": "python",
  "tool": "ruff",
  "error_count": 5,
  "warning_count": 12,
  "issues": [
    {
      "file": "auth.py",
      "line": 45,
      "column": 10,
      "severity": "error",
      "rule": "F401",
      "message": "Unused import: 'os'",
      "suggestion": "Remove unused import"
    },
    {
      "file": "payment.py",
      "line": 89,
      "column": 5,
      "severity": "warning",
      "rule": "C901",
      "message": "Function too complex (complexity: 15)",
      "suggestion": "Refactor into smaller functions"
    }
  ]
}

---

How to Use

Automatic Invocation

This Skill is automatically invoked by Claude when:

• Tech Lead is reviewing code changes
• Before approving pull requests
• Code quality issues are suspected

Manual Test

# Run linting
bash .claude/skills/lint-check/lint.sh

# Or PowerShell
.\.claude\skills\lint-check\lint.ps1

---

Installation Requirements

Python Projects

# Recommended: ruff (fast)
pip install ruff

# Or: pylint (comprehensive)
pip install pylint

JavaScript Projects

npm install --save-dev eslint
npx eslint --init

Go Projects

go install github.com/golangci/golangci-lint/cmd/golangci-lint@latest

Ruby Projects

gem install rubocop

Java Projects

Maven (pom.xml):

<!-- Checkstyle for style checking -->
<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-checkstyle-plugin</artifactId>
  <version>3.3.1</version>
  <configuration>
    <configLocation>google_checks.xml</configLocation>
  </configuration>
</plugin>

<!-- PMD for code quality -->
<plugin>
  <groupId>org.apache.maven.plugins</groupId>
  <artifactId>maven-pmd-plugin</artifactId>
  <version>3.21.2</version>
</plugin>

Gradle (build.gradle):

plugins {
  id 'checkstyle'
  id 'pmd'
}

checkstyle {
  toolVersion = '10.12.5'
  configFile = file('config/checkstyle/google_checks.xml')
}

pmd {
  toolVersion = '6.55.0'
  ruleSets = ['category/java/bestpractices.xml', 'category/java/errorprone.xml']
}

---

Interpreting Results

Severity Levels

Errors (Must Fix):

• Syntax errors
• Unused imports/variables
• Undefined names
• Breaking style violations

Warnings (Should Fix):

• High complexity functions
• Code smells
• Deprecated patterns
• Style inconsistencies

Info (Nice to Fix):

• Minor style preferences
• Optimization opportunities
• Documentation suggestions

Common Issues

Python:

• F401: Unused import
• E501: Line too long (>88 chars for ruff, >79 for PEP 8)
• C901: Function too complex
• N803: Argument name should be lowercase

JavaScript:

• no-unused-vars: Unused variables
• eqeqeq: Use === instead of ==
• no-console: Console statements in production code
• complexity: Function too complex

Go:

• gofmt: Code not formatted
• govet: Suspicious constructs
• staticcheck: Static analysis issues
• errcheck: Unchecked errors

---

Configuration

Python: pyproject.toml (ruff)

[tool.ruff]
line-length = 100
select = ["E", "F", "W", "C", "N"]
ignore = ["E501"]  # Ignore line too long

[tool.ruff.per-file-ignores]
"tests/*" = ["F401"]  # Allow unused imports in tests

JavaScript: .eslintrc.json

{
  "extends": "eslint:recommended",
  "rules": {
    "no-console": "warn",
    "eqeqeq": "error",
    "complexity": ["warn", 10]
  }
}

Go: .golangci.yml

linters:
  enable:
    - gofmt
    - govet
    - staticcheck
    - errcheck

---

Troubleshooting

Issue: Linter not found

Solution: Install the appropriate linter for your language (see Installation Requirements)

Issue: Too many warnings

Solution: Configure linter to ignore certain rules or directories. Create config file (.ruff.toml, .eslintrc, etc.)

Issue: False positives

Solution: Use inline comments to suppress specific warnings:

• Python: # noqa: F401
• JavaScript: // eslint-disable-next-line no-console
• Go: //nolint:errcheck

---

Implementation

See lint.sh (bash) or lint.ps1 (PowerShell) for full implementation details.

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Credits

This Skill uses industry-standard linting tools:

• ruff: Fast Python linter (Astral)
• pylint: Python code analyzer (PyCQA)
• eslint: JavaScript/TypeScript linter (OpenJS Foundation)
• golangci-lint: Go linters aggregator
• rubocop: Ruby static analyzer (RuboCop)
• Checkstyle: Java style checker (Checkstyle)
• PMD: Java code quality analyzer (PMD)