Conciseness

The body is mostly efficient domain-specific policy content, but it duplicates itself: the '### Valid License Headers' heading (line 61) is empty while the actual header examples appear later under '## Valid License Headers for WordPress Plugins', the 'GPL Versions Summary' table is repeated nearly verbatim in references/gpl-compliance.md, and 'Quick Reference: WordPress GPL Requirements' overlaps the 'License Compliance Checklist'. This fits 'mostly efficient but includes some unnecessary explanation or could be tightened' rather than score 4's 'minor instances'.

Actionability

For an instruction-only review skill, guidance is fully concrete: copy-paste-ready valid license header strings (e.g., 'License: GPL-2.0-or-later / License URI: https://www.gnu.org/licenses/gpl-2.0.html'), an explicit verification checklist, named violation patterns ('non-commercial, no-resale, forced backlink'), and precise naming thresholds ('at least 5 alphanumeric characters', '<= 50 chars'). It is not score 4 because no key execution detail is missing.

Workflow Clarity

The Procedure gives a clear 6-step sequence with explicit checkpoints and error-recovery paths: every licensing issue 'must cite Guideline 1 and include the file path and exact license string', 'If a license is not clearly GPL-compatible, do not guess. Check the GNU license list', and dual-license packages get explicit verification. A full checklist is provided, matching the score-5 anchor; the score-4 anchor's 'minor validation gaps' do not apply.

Progressive Disclosure

Three real one-level-deep references are well signaled with load conditions ('Load this reference file only when a full guideline audit is requested'), and quick-reference digests stay inline while details are deferred. However, the empty '### Valid License Headers' heading whose content lives under a differently named later section, and the GPL version table duplicated from gpl-compliance.md, are minor organization gaps that keep it below the 'easy navigation' score-5 anchor.

Specificity

The description enumerates many concrete actions — 'reviewing WordPress plugins for GPL compliance, checking license headers or compatibility, evaluating upsell/freemium/trialware patterns, validating plugin naming or trademark rules, checking plugin slugs, understanding why a plugin was rejected' — comprehensively covering the skill's capabilities. It exceeds the score-4 anchor ('several specific actions; minor gaps') because no meaningful capability of the skill is left out.

Completeness

Both 'what' (review/check/evaluate/validate plugin compliance against the 18 Plugin Directory guidelines) and 'when' (explicit 'Use when...' list of concrete triggers, plus 'even if the user doesn't mention "guidelines" explicitly') are clearly and explicitly answered. The 'when' is more explicit than the score-4 anchor allows.

Trigger Term Quality

Natural user phrasing is thoroughly covered: 'GPL compliance', 'license headers', 'upsell', 'freemium', 'trialware', 'plugin slugs', 'trademark', 'rejected from WordPress.org', 'guidelines', including synonym families (upsell/freemium/trialware). This matches the comprehensive-synonyms anchor rather than score 4 ('a few natural terms missing').

Distinctiveness Conflict Risk

It occupies a clear niche (WordPress.org Plugin Directory guidelines) with distinct, domain-specific triggers (GPL headers, trialware, slugs, WordPress.org rejection), so conflict with other skills is minimal. It is far more distinct than the score-4 example ('Works with PDF and Word document files').