Skill Validator Validate SKILL.md files against the Agent Skills specification and Claude Code extensions. When to Run - After creating a new skill - After modifying a skill's SKILL.md frontmatter - Before committing skill changes - During periodic repo audits Validation Rules Required Fields (Agent Skills Spec) Every SKILL.md must have YAML frontmatter with: - — kebab-case, matches directory name - — 1-3 sentences, under 1024 chars, starts with verb or domain noun Metadata Block and must be inside , never top-level: Forbidden Fields These are not part of any spec: - / — removed in 2026-04 mi…