authoring skills and rules Shipped
What this lens looks for
Skill design rules — check inventory first, version from day one, session version check, use $ARGUMENTS and ${CLAUDE_SKILL_DIR}, description under 200 chars, atomic permission prompt, error handling; Rule design rules — imperative tone (MUST/MUST NOT), explicit file paths, single concern, MUST NOT section required, enforcement mechanism, deterministic instructions; Agent design — scope tool access, set maxTurns, clear system prompt
What its verifier checks
Skill has version in frontmatter and prints it on invocation; skill description under 200 chars; rule uses RFC 2119 keywords; rule lists explicit file paths for all references; agent has maxTurns set; /lint-skill, /lint-rule, or /lint-agent run after every change