skill validator

Skill Validator

Validates SKILL.md files in the skills/ directory against Anthropic's requirements using skills/skill-validator/scripts/validate-skills.py.

What it checks

• name field present and matches the skill's directory name
• description field present
• No XML tags (<...>) in description — Claude Code rejects these on load
• Combined description + when_to_use length ≤ 1,536 characters
• Frontmatter parsed via PyYAML (handles block scalars correctly)
• Packaging simulation writes skills/<name>/.test/<name>.skill and reports archive size

Run

Validate all skills:

# Windows
.venv/Scripts/python skills/skill-validator/scripts/validate-skills.py

# Linux / macOS
.venv/bin/python skills/skill-validator/scripts/validate-skills.py

Validate one skill by name:

# Windows
.venv/Scripts/python skills/skill-validator/scripts/validate-skills.py <skill-name>

# Linux / macOS
.venv/bin/python skills/skill-validator/scripts/validate-skills.py <skill-name>

Skip packaging simulation:

# Windows
.venv/Scripts/python skills/skill-validator/scripts/validate-skills.py --no-package

# Linux / macOS
.venv/bin/python skills/skill-validator/scripts/validate-skills.py --no-package

Exit code 0 = all pass. Exit code 1 = one or more failures.

Setup

Requires Python in .venv:

python -m venv .venv
pip install -r requirements.txt