Conciseness

The body is lean bullets throughout, assumes Claude's competence (never explains WordPress, REST, or PHP basics), and every reference blurb states only its decision-relevant purpose. Version mentions ("WP < 6.9") are conditional guidance, not time-sensitive filler, so nothing earns trimming.

Actionability

Concrete, executable-in-substance guidance: exact search strings ("wp_register_ability(", "wp-abilities/v1"), exact meta flags ("readonly: true", "show_in_rest: true"), and per-step reference pointers. Not 5 because there is no inline copy-paste-ready code — registration code and init hook names are deferred to references.

Workflow Clarity

A clear 6-step sequence (availability → existing usage → categories → registration → REST exposure → JS consumption) plus a Verification section and a Failure-modes section that maps symptoms to causes as a feedback loop. Not 5 because validation checkpoints live in a separate section rather than inline in the procedure, and REST verification lacks an exact command; some checks are conditional ("if applicable").

Progressive Disclosure

The body is a genuine overview that splits detail across 9 one-level-deep references, each clearly signaled with a stated purpose (e.g., "read references/grouping-heuristic.md first — it keeps you from shipping one atomic ability per REST operation"). All 9 cited files exist in ./references/ with no orphan files and no nested references.

Specificity

Lists several concrete actions ("defining abilities, categories, meta, REST exposure, and permissions checks") alongside exact API symbols (wp_register_ability, /wp-json/wp-abilities/v1/*), but omits JS consumption and the debugging workflows the body covers, so coverage has minor gaps rather than being comprehensive.

Completeness

Explicitly answers both: the "Use when working with the WordPress Abilities API…" clause gives concrete trigger phrases, and the action list clearly states what the skill does. Not 4 because the 'when' is explicit and specific, not weakly implied.

Trigger Term Quality

Good keyword coverage across PHP functions, the REST namespace, and the @wordpress/abilities package — terms a user working in this domain would naturally say — but natural debugging phrases like "ability doesn't show up" (listed as triggers in the body) are missing, so it falls short of the comprehensive-synonyms anchor.

Distinctiveness Conflict Risk

Clear niche anchored by unique symbols (wp_register_ability, wp_register_ability_category, @wordpress/abilities) that no adjacent WordPress REST or general skill would share, giving minimal conflict risk. Not 4 — there is no meaningful overlap with closely related skills.