rule structure reference Shipped
What this lens looks for
Rules are plain .md files (no required frontmatter schema), lowercase kebab-case filename, per-turn cost model (rules in .claude/rules/ injected every turn); quality criteria — imperative tone, deterministic, explicit file refs, no vague directives; optimization — under 200 lines/8KB, inline small content, reference large, globs frontmatter for scoped rules
What its verifier checks
Rule filename is lowercase kebab-case; no uppercase stem unless identity file; per-turn cost reviewed (size ×turns = budget impact); large reference material moved to on-demand reads