Conciseness

Dense, imperative rules with a compact decision table and no padding on concepts Claude already knows. Minor trims remain: the "Source Of Truth" section carries maintenance-meta text ("confirm that Epicenter's installed version matches the source being read... dependency freshness is handled outside this skill") and the "error !== null" discriminator rule appears in two sections. Not 5 because of this small redundancy; well above 3.

Actionability

Fully executable, copy-paste-ready examples cover the common cases: tryAsync with fetch and a defineErrors factory, unwrap(await openDocument(id)), and void save().then((result) => toastOnError(result, 'Save failed')), plus a concrete contract-selection table. Anchored rules ("Never construct Err(null)") are exact and followable.

Workflow Clarity

The decision flow is clearly sequenced (choose contract → cross boundaries → consume Err branches → own the Promise) and closes with a 5-item "Final Check" checklist. Not 5 because there are no explicit validate/fix feedback-loop steps, though the skill is decision guidance rather than a destructive or batch pipeline, so the workflow-clarity cap does not apply; well above 3 given the checklist.

Progressive Disclosure

Three one-level-deep references (wrapping-boundaries.md, toast-on-error.md, http-boundaries.md) — all verified to exist — each gated by an explicit read-when condition tied to a concrete decision point. The body stays a lean overview and the split is appropriate, matching the top anchor.

Specificity

Lists multiple concrete actions covering the domain comprehensively: "replacing try/catch", "adding trySync or tryAsync", "choosing fallback or propagation", "mapping errors", and "preserve failures at boundaries". Nothing significant is missing from the skill's stated scope.

Completeness

Explicitly answers both what ("Apply Wellcrafted Result patterns to fallible operations and preserve failures at boundaries") and when ("Use when replacing try/catch, adding trySync or tryAsync, choosing fallback or propagation, or mapping errors") with concrete trigger phrases. Matches the top anchor exactly.

Trigger Term Quality

Good natural-keyword coverage ("try/catch", "fallback", "mapping errors", "trySync/tryAsync") but misses common synonyms a user might say, such as "error handling", "exceptions", or "Result type". Not 5 because a few natural trigger phrases are absent; not 3 because coverage is clearly more than partial.

Distinctiveness Conflict Risk

Clear niche (Wellcrafted Result boundary handling) with distinct triggers, but fairly general phrases like "choosing fallback" and "mapping errors" carry minor overlap risk with closely related error-handling skills. Distinct enough to be above anchor 3, not niche-exclusive enough for 5.