Conciseness

The body is lean, assumes Claude's competence, and explains nothing Claude already knows — close to the top anchor. It is not a 5 because of minor trimmable content: the opening sentence 'This skill provides guidance for developing WooCommerce backend PHP code according to project standards and conventions.' merely restates the frontmatter description.

Actionability

The in-body guidance is concrete in places — 'Place new internal classes in `src/Internal/`', 'Use PSR-4 autoloading with `Automattic\WooCommerce` namespace', and a fully executable version-determination procedure — but the primary instruction path delegates all convention detail to seven referenced files ('See [file-entities.md](file-entities.md)...') that do not exist in the bundle, so key executable details are missing. Not a 4 because following the main instructions dead-ends rather than yielding mostly executable guidance.

Workflow Clarity

The Version Information section gives a clear sequenced procedure (read `$version` in `includes/class-woocommerce.php` on trunk, strip `-dev`), and 'Run linting and tests before committing changes' is a checkpoint, but it is implicit with no commands given, and there is no validation or error-recovery loop for the code-modification work the skill directs. This matches the 'steps listed but validation gaps' anchor rather than 4, which requires most checkpoints to be explicit.

Progressive Disclosure

The SKILL.md structure itself is well organized — a topical index with clearly signaled, one-level-deep references per topic — but every one of the seven referenced files (file-entities.md, code-entities.md, coding-conventions.md, hooks.md, dependency-injection.md, data-integrity.md, unit-tests.md) is missing from the bundle, so the navigation promise fails entirely. This sits noticeably below the midpoint between 'impossible to navigate' (1) and 'good structure' (3/4): the overview is clean but the disclosed content does not exist.

Specificity

The description lists several specific actions — 'Add or modify WooCommerce backend PHP code', 'creating new classes, methods, hooks' — with concrete artifacts, placing it at the 'several specific actions; minor gaps' anchor. It is not a 5 because it does not enumerate the full breadth of backend work covered by the skill (e.g., naming conventions, dependency injection, data integrity, testing), staying at the level of 'classes, methods, hooks'.

Completeness

It explicitly answers 'what' ('Add or modify WooCommerce backend PHP code following project conventions') and 'when' with a concrete trigger clause ('Use when creating new classes, methods, hooks, or modifying existing backend code in WooCommerce projects'), matching the top anchor's both-what-and-when-with-concrete-trigger-phrases pattern. It is not lower because neither half is missing or merely implied.

Trigger Term Quality

Natural terms a user would say are present: 'WooCommerce', 'backend PHP', 'classes', 'methods', 'hooks', 'modifying existing backend code'. It falls short of the comprehensive anchor because common variations like '.php', 'plugin', 'extension', or 'WordPress' are absent, though the core vocabulary is well chosen.

Distinctiveness Conflict Risk

The 'WooCommerce backend' niche is clear and the triggers ('WooCommerce projects', 'hooks') are distinct from most skills, sitting between 'mostly distinct' and 'clear niche with minimal conflict risk'. It is not a 5 because a general WordPress plugin development or PHP conventions skill would plausibly trigger on the same phrases.