mdmend

Fast, zero-dependency Markdown linter and fixer. Fixes 48 common Markdown issues instantly.

Installation

npm install -g mdmend
# or
npx mdmend lint .

Usage

# Lint current directory
mdmend lint .

# Lint a single file
mdmend lint README.md

# Auto-fix all fixable violations
mdmend fix .

# Preview fixes without writing
mdmend fix . --dry-run

# Show unified diffs
mdmend fix . --diff

# Apply heuristic fixes (language detection, URL wrapping)
mdmend fix . --aggressive

# Lint only specific rules
mdmend lint . --only MD040,MD034

# Show rule frequency breakdown
mdmend lint . --stats

# List all available rules
mdmend rules list

# Show details about a specific rule
mdmend rules info MD040

# JSON output (for CI/tooling integration)
mdmend lint . --output json

# Advisory CI mode (always exits 0)
mdmend lint . --exit-zero

# Show suggestions for heuristic rules
mdmend suggest .

Rules

mdmend implements 48 rules (MD003–MD058) covering:

• Heading style and structure
• List formatting
• Code fence language detection (MD040)
• Bare URL wrapping (MD034)
• Table formatting
• Blank line consistency
• And much more

38 of the 48 rules are auto-fixable with mdmend fix.

mdmend rules list          # Show all rules
mdmend rules list --fixable  # Show only auto-fixable rules
mdmend rules info MD040    # Details about a specific rule

CI Integration

# GitHub Actions
- name: Lint Markdown
  run: npx mdmend lint . --output json --exit-zero

# Fail CI if more than 10 violations
mdmend lint . --max-violations 10

Supported Platforms

| Platform | x64 | arm64 | |----------|-----|-------| | macOS | yes | yes | | Linux | yes | yes | | Windows | yes | — |

Links

• GitHub
• Rules Reference
• Bug Reports

License

MIT