Conciseness

The bulk is dense applied guidance (tables, before/after copy patterns), but there is unnecessary material: a two-paragraph "About the Author" section ("Steve Krug is a usability consultant who has been helping companies... since the 1990s"), affiliate-tagged "Further Reading" links, "Why it works" paragraphs re-explaining well-known principles, and a "Core Principle" section that repeats the intro ("Don't Make Me Think" appears as both section thesis and restated foundation). Not 2 because most sections are high-signal rather than padded; not 4 because the biographical and explanatory material is clearly trimmable.

Actionability

For an instruction-only skill the guidance is fully executable: an explicit output protocol ("rate them 0-10... Always provide the current score and specific improvements needed to reach 10/10"), a concrete severity scale table (0-4 with priorities), before/after copy rewrites ("Before: 'Please kindly note that you will need to enter your password...' After: 'Enter your password to continue.'"), and specific numeric standards ("Minimum 44x44 px touch targets", "WCAG AA minimum (4.5:1 contrast ratio)"). Specific examples cover the common cases.

Workflow Clarity

All the pieces of an audit workflow exist — the Quick Diagnostic question table, the severity rating scale, the 0-10 scoring protocol, and method sequencing ("Heuristic evaluation | Before user testing") — but they are never assembled into an explicit ordered process with checkpoints; the actual audit procedure is delegated to references/audit-template.md. Not 4 because the sequence for conducting an evaluation must be inferred from section order rather than followed as stated steps.

Progressive Disclosure

All seven referenced files (krug-principles.md, nielsen-heuristics.md, audit-template.md, dark-patterns.md, wcag-checklist.md, cultural-ux.md, heuristic-conflicts.md) exist in references/, are one level deep, clearly signaled inline ("See: [references/krug-principles.md] for full Krug methodology"), and indexed in a "Reference Files" section with descriptions. Not 5 because the four Krug law sections carry roughly 150 lines of inline tables, copy patterns, and ethical boundaries that overlap with krug-principles.md, making the overview heavier than a clean split.

Specificity

"Evaluate and improve interface usability using heuristic analysis" names the domain and two concrete actions, but the remainder is coverage description ("Covers Nielsens 10 heuristics, severity ratings, and information architecture") and trigger clauses rather than additional specific actions. It falls below anchor 4, which expects several distinct concrete actions listed, and clearly above anchor 2's minimal/generic actions.

Completeness

Explicitly answers "what" ("Evaluate and improve interface usability using heuristic analysis") and "when" ("Use when the user mentions...", "Also trigger when reviewing a design for usability issues") with concrete trigger phrases. This matches anchor 5 exactly; anchor 4 would require the when-clause to be less explicit or specific than it is here.

Trigger Term Quality

Nine natural quoted trigger phrases ("usability audit", "UX review", "users are confused", "heuristic evaluation", "form usability", "navigation problems", "Nielsen heuristics", "cognitive walkthrough", "usability testing") plus contextual triggers ("improving form completion rates", "evaluating information architecture and navigation") give comprehensive coverage including synonyms and phrasings users would actually say. Not below 5 because no common variation of the request is missing.

Distinctiveness Conflict Risk

Clear niche (usability heuristic evaluation) with distinct trigger terms, plus explicit disambiguation against neighbors: "For visual design fixes, see refactoring-ui. For conversion-focused audits, see cro-methodology." Minimal conflict risk; no anchor below fits better.