Conciseness

Every section carries only bestax/bulma-specific facts Claude cannot know (gzip-vs-raw expectations, flavor size table, pnpm dependency constraint, $primary turquoise reversion, no-helpers gate), with no generic CSS/Sass/gzip tutorials, and size drift is hedged ("Measured sizes drift slightly between releases — hence measure") instead of pinning versions. Not 4: there is no over-explanation to trim — each token is library-specific operational data.

Actionability

Fully executable throughout: `wc -c dist/assets/*.css`, `gzip -c … | wc -c`, exact per-flavor import strings, `npm install bulma` / `-D sass`, a complete ordered `styles.scss` `@use` example, and concrete grep targets (helper prop names, `is-*`/`m*-*` class patterns). Not 4: the common cases are covered copy-paste ready, with no gaps requiring invention.

Workflow Clarity

Clear cheapest-first sequence (measure → flavor switch → modular Sass → hygiene) with an explicit validation loop ("Re-measure after every step… Never claim a saving without a number"), a pre-flight checklist (the no-helpers helper-prop grep gate), and an explicit abort path ("your CSS is already fine" is a valid outcome). Not 4: checkpoints are explicit rather than implicit, including the feedback loop of before/after delta reporting.

Progressive Disclosure

The body is a decision-oriented overview (measure, decision flow, three levers) while Lever 2 depth (component→partial mapping, authoritative extras inventory, worked example) is offloaded to references/modular-build.md, which exists, is one level deep, and is clearly signaled both inline in Lever 2 and in a References section. Not 4: the split is appropriate and navigation is easy with no buried or nested references.

Specificity

"measure raw and gzip size, then apply the cheapest lever that fits (lighter prebuilt CSS flavor, hand-rolled modular Sass build, import and icon-asset hygiene)" lists multiple specific concrete actions with comprehensive coverage of the skill's domain. Not 4: no minor gaps — measurement plus all three levers are explicitly named.

Completeness

Explicitly answers both: what ("Reduce the built CSS size of an app using @allxsmith/bestax-bulma — measure raw and gzip size, then apply the cheapest lever that fits") and when ("Use when the CSS bundle looks too big, a size budget or Lighthouse audit flags stylesheet weight…") with concrete trigger phrases. Not 4: the 'when' clause is explicit and specific, not merely present.

Trigger Term Quality

Natural user phrasings are comprehensively covered: "CSS bundle looks too big", "size budget", "Lighthouse audit flags stylesheet weight", "switching bestax.css to a versions/*.css flavor", "modular @use Bulma/Sass build", including file names and synonyms (bundle/stylesheet weight, size budget). Not 4: no commonly-said trigger for this niche is missing.

Distinctiveness Conflict Risk

Clear niche pinned to the specific library (@allxsmith/bestax-bulma) with library-specific triggers (bestax.css, versions/*.css, @use Bulma/Sass), giving minimal conflict risk with generic CSS or build skills. Not 4: the overlap risk is essentially nil, not minor.