Skill Md Validator

SKILL.md Validator

A utility for validating SKILL.md files to ensure they follow best practices and are complete.

What It Checks

Required Fields

• name: - Skill name (required)
• description: - Skill description (required)
• version: - Semantic version (required)

Format Validation

• YAML frontmatter starts with ---
• YAML frontmatter ends with ---
• Proper YAML syntax
• Valid semantic version

Content Validation

• Content exists after frontmatter
• Minimum content length (50 characters)
• Contains Markdown headers
• No obvious formatting issues

Usage

Basic Validation

./validate_skill.sh path/to/SKILL.md

Validate All Skills

for skill in examples/.claude/skills/*/SKILL.md; do
    echo "Validating $skill..."
    ./validate_skill.sh "$skill"
    echo
done

Integration with CI/CD

# .github/workflows/validate-skills.yml
name: skill-md-validator

on: [push, pull_request]

jobs:
  validate:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - name: Validate SKILL.md files
        run: |
          for skill in examples/.claude/skills/*/SKILL.md; do
            ./examples/.claude/skills/skill-validator/validate_skill.sh "$skill"
          done

Validation Output

Success Example

🔍 Validating code-reviewer/SKILL.md...

✅ YAML frontmatter starts correctly
✅ YAML frontmatter formatted correctly
✅ Found required field: name:
✅ Found required field: description:
✅ Found required field: version:
✅ Content present (2540 characters)
✅ Contains Markdown headers

🎉 Validation complete! SKILL.md looks good.

Failure Example

🔍 Validating bad-example/SKILL.md...

❌ Missing YAML frontmatter start (---)

Validation failed. Please fix the issues above.

Best Practices

Writing SKILL.md Files

1. Start with YAML frontmatter

   ---
   name: "My Skill"
   description: "What this skill does"
   version: "1.0.0"
   ---
   

2. Add meaningful content

   • Include clear instructions
   • Provide examples
   • Use proper Markdown formatting
   • Add sections with headers

3. Follow naming conventions

   • Use kebab-case for skill IDs
   • Use semantic versioning
   • Be descriptive but concise

4. Include metadata

   • Author information
   • Relevant tags
   • Dependencies on other skills

Common Issues

Missing Required Fields

❌ Error: Missing required field: name:

Fix: Add the name field to YAML frontmatter
---
name: skill-md-validator
---

Invalid YAML

❌ Error: YAML parsing error

Fix: Ensure proper YAML syntax
- Use spaces for indentation (not tabs)
- Quote strings with special characters
- Properly format lists

Insufficient Content

⚠️  Warning: Content seems very short (< 50 chars)

Fix: Add more detailed instructions and examples

Integration Examples

Pre-commit Hook

#!/bin/bash
# .git/hooks/pre-commit

for file in $(git diff --cached --name-only | grep SKILL.md); do
    if ! ./examples/.claude/skills/skill-validator/validate_skill.sh "$file"; then
        echo "❌ Validation failed for $file"
        exit 1
    fi
done

Makefile Target

# Makefile

.PHONY: validate-skills
validate-skills:
	@echo "Validating all SKILL.md files..."
	@for skill in examples/.claude/skills/*/SKILL.md; do \
		./examples/.claude/skills/skill-validator/validate_skill.sh "$$skill"; \
	done

Extending the Validator

You can extend this validator to check for:

1. Custom fields

   if ! grep -q "author:" "$SKILL_FILE"; then
       echo "⚠️  Warning: Missing author field"
   fi
   

2. Code examples

   if ! grep -q '```' "$SKILL_FILE"; then
       echo "⚠️  Warning: No code examples found"
   fi
   

3. Tag conventions

   tags=$(sed -n '/^---$/,/^---$/p' "$SKILL_FILE" | grep "^tags:" | tail -n +1)
   if [ -z "$tags" ]; then
       echo "⚠️  Warning: No tags defined"
   fi
   

Related Tools

• yamllint - YAML linter
• markdownlint - Markdown linter
• vale - Prose linter for documentation