markdownlint

name	markdownlint
description	This skill should be used when users need to format, clean, lint, or validate Markdown files using the markdownlint-cli2 command-line tool. Use this skill for tasks involving Markdown (including Quarto Markdown `.qmd`) file quality checks, automatic formatting fixes, enforcing Markdown style rules, or identifying Markdown syntax issues.

Markdownlint Skill

Contents

• Markdownlint Skill
  • Contents
  • Project Configuration
  • Basic Usage
  • Common Operations
    • Lint Specific Paths
    • Auto-Fix
    • Process stdin
  • Workflow
    • Standard Lint-Fix-Verify Cycle
    • Safe Fix with Backup
  • Cross-Platform Usage
  • Troubleshooting
    • No Files Matched
    • Too Many Issues
    • Configuration Not Loading
  • References
  • Installation

Project Configuration

IMPORTANT: This project uses .markdownlint.yaml. Always follow these rules:

Rule	Setting	Notes
MD040	Enabled	Always specify language for code fences
MD007	2 spaces	List indentation
MD024	Siblings only	Duplicate headings allowed under different parents
MD013	Disabled	No line length restrictions
MD033	Disabled	Inline HTML allowed
MD041	Disabled	Files don't need to start with H1
MD038	Disabled	Spaces in code spans allowed
MD036	Disabled	Emphasis as heading allowed

Basic Usage

# Lint files
markdownlint-cli2 "**/*.md"
markdownlint-cli2 README.md

# Auto-fix issues
markdownlint-cli2 --fix "**/*.md"

# Exclude directories
markdownlint-cli2 "**/*.md" "#node_modules" "#vendor"

Common Operations

Lint Specific Paths

markdownlint-cli2 README.md                    # Single file
markdownlint-cli2 "docs/**/*.md"               # Directory
markdownlint-cli2 "*.md" "docs/**/*.md"        # Multiple patterns
markdownlint-cli2 .                            # Current directory

Auto-Fix

markdownlint-cli2 --fix "**/*.md"              # Fix all files
markdownlint-cli2 --fix README.md              # Fix single file

Process stdin

cat README.md | markdownlint-cli2 -

Workflow

Standard Lint-Fix-Verify Cycle

1. Run lint check: markdownlint-cli2 "**/*.md"
2. Review reported issues
3. Apply auto-fix: markdownlint-cli2 --fix "**/*.md"
4. Re-run lint to verify: markdownlint-cli2 "**/*.md"
5. Review changes: git diff
6. Commit when satisfied

Safe Fix with Backup

1. Stage current state: git add .
2. Create backup commit: git commit -m "Backup before markdownlint fix"
3. Apply fixes: markdownlint-cli2 --fix "**/*.md"
4. Review changes: git diff
5. Commit fixes or reset: git add . && git commit -m "Apply markdownlint fixes"

Cross-Platform Usage

For maximum compatibility:

• Quote glob patterns: markdownlint-cli2 "**/*.md"
• Use # for negation: markdownlint-cli2 "**/*.md" "#vendor" (not !)
• Use forward slashes: docs/**/*.md (works on all platforms)
• Stop option processing: markdownlint-cli2 -- "special-file.md"

Troubleshooting

No Files Matched

• Verify glob patterns are quoted
• Check file extensions (.md vs .markdown)
• Ensure negated patterns don't exclude everything

Too Many Issues

1. Start with auto-fix: markdownlint-cli2 --fix "**/*.md"
2. Disable problematic rules temporarily
3. Address remaining issues incrementally

Configuration Not Loading

• Verify configuration file name matches expected patterns
• Validate JSON/YAML syntax
• Use --config to explicitly specify the file

References

• Rules Reference - Complete rule descriptions
• Configuration Examples - Config templates and patterns
• Official Documentation
• All Rules

Installation

npm install -g markdownlint-cli2    # npm
brew install markdownlint-cli2      # Homebrew
markdownlint-cli2 --help            # Verify installation