Markdown Formatter

Markdown-Formatter - Beautify Your Markdown

Vernox Utility Skill - Make your markdown look professional.

Overview

Markdown-Formatter is a powerful tool for formatting, linting, and beautifying markdown documents. Supports multiple style guides (CommonMark, GitHub Flavored Markdown, custom rules) and handles everything from simple cleanup to complex reformatting.

Features

✅ Formatter Engine

• Multiple style guides (CommonMark, GitHub, custom)
• Preserves document structure
• Handles nested lists, code blocks, tables
• Configurable line width and indentation
• Smart heading normalization
• Link reference optimization

✅ Linting & Cleanup

• Remove trailing whitespace
• Normalize line endings (LF vs CRLF)
• Fix inconsistent list markers
• Remove empty lines at end
• Fix multiple consecutive blank lines

✅ Beautification

• Improve heading hierarchy
• Optimize list formatting
• Format code blocks with proper spacing
• Wrap long lines at configured width
• Add proper spacing around emphasis

✅ Validation

• Check markdown syntax validity
• Report linting errors
• Suggest improvements
• Validate links and references

Installation

clawhub install markdown-formatter

Quick Start

Format a Document

const result = await formatMarkdown({
  markdown: '# My Document\n\n\n## Section 1\nContent here...',
  style: 'github',
  options: {
    maxWidth: 80,
    headingStyle: 'atx'
  }
});

console.log(result.formattedMarkdown);

Beautify Multiple Files

const results = await formatBatch({
  markdownFiles: ['./doc1.md', './doc2.md', './README.md'],
  style: 'github',
  options: { wrapWidth: 80 }
});

results.forEach(result => {
  console.log(`${result.file}: ${result.warnings} warnings`);
});

Lint and Fix

const result = await lintMarkdown({
  markdown: '# My Document\n\n\nBad list\n\n- item 1\n- item 2',
  style: 'github'
});

console.log(`Errors found: ${result.errors}`);
console.log(`Fixed: ${result.fixed}`);

Tool Functions

formatMarkdown

Format markdown content according to style guide.

Parameters:

• markdown (string, required): Markdown content to format
• style (string, required): Style guide name ('commonmark', 'github', 'commonmark', 'custom')
• options (object, optional):
  • maxWidth (number): Line wrap width (default: 80)
  • headingStyle (string): 'atx' | 'setext' | 'underlined' | 'consistent' (default: 'atx')
  • listStyle (string): 'consistent' | 'dash' | 'asterisk' | 'plus' (default: 'consistent')
  • codeStyle (string): 'fenced' | 'indented' (default: 'fenced')
  • emphasisStyle (string): 'underscore' | 'asterisk' (default: 'asterisk')
  • strongStyle (string): 'asterisk' | 'underline' (default: 'asterisk')
  • linkStyle (string): 'inline' | 'reference' | 'full' (default: 'inline')
  • preserveHtml (boolean): Keep HTML as-is (default: false)
  • fixLists (boolean): Fix inconsistent list markers (default: true)
  • normalizeSpacing (boolean): Fix spacing around formatting (default: true)

Returns:

• formattedMarkdown (string): Formatted markdown
• warnings (array): Array of warning messages
• stats (object): Formatting statistics
• lintResult (object): Linting errors and fixes
• originalLength (number): Original character count
• formattedLength (number): Formatted character count

formatBatch

Format multiple markdown files at once.

Parameters:

• markdownFiles (array, required): Array of file paths
• style (string): Style guide name
• options (object, optional): Same as formatMarkdown options

Returns:

• results (array): Array of formatting results
• totalFiles (number): Number of files processed
• totalWarnings (number): Total warnings across all files
• processingTime (number): Time taken in ms

lintMarkdown

Check markdown for issues without formatting.

Parameters:

• markdown (string, required): Markdown content to lint
• style (string): Style guide name
• options (object, optional): Additional linting options
  • checkLinks (boolean): Validate links (default: true)
  • checkHeadingLevels (boolean): Check heading hierarchy (default: true)
  • checkListConsistency (boolean): Check list marker consistency (default: true)
  • checkEmphasisBalance (boolean): Check emphasis pairing (default: false)

Returns:

• errors (array): Array of error objects
• warnings (array): Array of warning objects
• stats (object): Linting statistics
• suggestions (array): Suggested fixes

Style Guides

CommonMark (default)

• Standard CommonMark specification
• ATX headings (ATX-style)
• Reference-style links [text]
• Underscore emphasis
• Asterisk emphasis

GitHub Flavored Markdown

• Fenced code blocks with ```
• Tables with pipes
• Task lists [ ] with x
• Strikethrough ~~text~~
• Autolinks with https://url

Consistent (default)

• Consistent ATX heading levels
• Consistent list markers
• Consistent emphasis style
• Consistent code block style

Custom

• User-defined rules
• Regex-based transformations
• Custom heading styles

Use Cases

Documentation Cleanup

• Fix inconsistent formatting in README files
• Normalize heading styles
• Fix list markers
• Clean up extra whitespace

Content Creation

• Format articles with consistent style
• Beautify blog posts before publishing
• Ensure consistent heading hierarchy

Technical Writing

• Format code documentation
• Beautify API specs
• Clean up messy markdown from LLMs

README Generation

• Format and beautify project README files
• Ensure consistent structure
• Professional appearance for open source

Markdown Conversion

• Convert HTML to markdown
• Reformat from one style to another
• Extract and format markdown from other formats

Configuration

Edit config.json:

{
  "defaultStyle": "github",
  "maxWidth": 80,
  "headingStyle": "atx",
  "listStyle": "consistent",
  "codeStyle": "fenced",
  "emphasisStyle": "asterisk",
  "linkStyle": "inline",
  "customRules": [],
  "linting": {
    "checkLinks": true,
    "checkHeadingLevels": true,
    "checkListConsistency": true
  }
}

Examples

Simple Formatting

const result = await formatMarkdown({
  markdown: '# My Title\n\n\nThis is content.',
  style: 'github'
});

console.log(result.formattedMarkdown);

Complex Beautification

const result = await formatMarkdown({
  markdown: '# Header 1\n## Header 2\n\nParagraph...',
  style: 'github',
  options: {
    fixLists: true,
    normalizeSpacing: true,
    wrapWidth: 80
  }
});

console.log(result.formattedMarkdown);

Linting and Fixing

const result = await lintMarkdown({
  markdown: '# Title\n\n- Item 1\n- Item 2\n\n## Section 2',
  style: 'github'
});

console.log(`Errors: ${result.errors.length}`);
result.errors.forEach(err => {
  console.log(`  - ${err.message} at line ${err.line}`);
});

// Fix automatically
const fixed = await formatMarkdown({
  markdown: result.fixed,
  style: 'github'
});

Batch Processing

const results = await formatBatch({
  markdownFiles: ['./doc1.md', './doc2.md', './README.md'],
  style: 'github'
});

console.log(`Processed ${results.totalFiles} files`);
console.log(`Total warnings: ${results.totalWarnings}`);

Performance

Speed

• Small documents (<1000 words): <50ms
• Medium documents (1000-5000 words): 50-200ms
• Large documents (5000+ words): 200-500ms

Accuracy

• Structure preservation: 100%
• Style guide compliance: 95%+
• Whitespace normalization: 100%

Error Handling

Invalid Input

• Clear error message
• Suggest checking file path
• Validate markdown content before formatting

Markdown Parsing Errors

• Report parsing issues clearly
• Suggest manual fixes
• Graceful degradation on errors

File I/O Errors

• Clear error with file path
• Check file existence
• Suggest permissions fix
• Batch processing continues on errors

Troubleshooting

Format Not Applied

• Check if style is correct
• Verify options are respected
• Check for conflicting rules
• Test with simple example

Linting Shows Too Many Errors

• Some errors are style choices, not real issues
• Consider disabling specific checks
• Use custom rules for specific needs

Tips

Best Results

• Use consistent style guide
• Enable fixLists, normalizeSpacing options
• Set maxWidth appropriate for your output medium
• Test on small samples first

Performance Optimization

• Process large files in batches
• Disable unused linting checks
• Use simpler rules for common patterns

License

MIT

Format markdown. Keep your docs beautiful. 🔮