Conciseness

The bulk is dense, domain-specific guidance, but there is real redundancy: the "Quick Rules (Non-Negotiable)" section restates Step 4 almost item-for-item (reduced-motion, GPU-safe properties, will-change removal, aria-hidden, mobile detection all appear twice), and the "Your Mindset" section is motivational padding ("Never build a flat, static page when this skill is active", "Think: Apple product pages, Awwwards winners"). This is more than the minor trims of anchor 4 but well above the padded verbosity of anchor 2, so it fits anchor 3.

Actionability

Guidance is copy-paste ready throughout: the exact prefers-reduced-motion CSS block, a quantified depth table ("DEPTH 0 → ... parallax: 0.10x | blur: 8px | scale: 0.70"), a complete HTML section architecture, a positioning formula (`right: calc(50% - [hero-half-width] - [gap])`), concrete clip-path values (`inset(0 0 100% 0)` → `inset(0)`), a pinned GSAP CDN URL, and exact commands (`scripts/inspect-assets.py`, `node scripts/validate-layers.js path/to/index.html`). It is not 4 because the common cases are covered with executable specifics rather than leaving minor gaps.

Workflow Clarity

The 5-step build workflow is clearly sequenced with three entry modes, user-facing checkpoints ("State your decisions to the user before building", "get confirmation before treating any background as a problem"), and a final validation step with an exact script and a list of what it checks. It is not 5 because no fix-and-revalidate loop is spelled out — the Validation section ends at "run the validation script" without instructing what to do on failure (Mode 3 Debug exists but is never tied to validation output); it is not 3 because the sequence and checkpoints are explicit, and the operations are generative rather than destructive.

Progressive Disclosure

Structure is strong: a reference table with "File | What's Inside | When to Read" columns clearly signals nine one-level-deep reference files, all of which exist in the bundle, and both referenced scripts exist. It is not 5 because Step 5 points to `assets/hero-section.html`, `assets/hero-section.css`, and `assets/hero-section.js` ("Full boilerplate", "Full CSS system", "Full JS engine") and no `assets/` directory exists in the bundle — three broken pointers; it is not 3 because references are clearly signaled and content is appropriately split between the overview and reference files.

Specificity

The description lists multiple concrete actions and techniques — "Build immersive, cinematic 2.5D interactive websites using scroll storytelling, parallax depth, text animations", plus a long enumerated list ("clip-path reveals... curtain drops, iris opens, card stacks, bleed typography") and a process commitment ("Always inspects, judges, and plans assets before coding"). This matches the anchor for comprehensive, specific concrete actions; it is not 4 because coverage of the domain's actions shows no gaps — every major capability category is named.

Completeness

Both what and when are explicit: the what is "Build immersive, cinematic 2.5D interactive websites using scroll storytelling, parallax depth, text animations, and premium scroll effects — no WebGL required", and the when is "Use this skill for any web design task" plus "Trigger on phrases like...". This matches the anchor that clearly answers both with concrete trigger phrases; it is not 4 because the when-clause is fully explicit rather than merely present.

Trigger Term Quality

Trigger coverage includes natural user phrasings — "make it feel alive", "Apple-style animation", "sections that overlap", "product rises between sections", "immersive", "scrollytelling" — alongside concrete feature keywords ("scroll animations, parallax, sticky sections, section overlaps"). This is comprehensive coverage including synonyms and colloquial variations; it is not 4 because even informal phrasings a user would naturally say are explicitly listed.

Distinctiveness Conflict Risk

Most listed techniques ("parallax", "clip-path reveals", "scrollytelling", "words that light up on scroll") are a distinct niche, but the over-claims "Use this skill for any web design task" and "Use aggressively for ANY web design task" broaden it to all web design, creating real overlap risk with general UI-design, landing-page, and frontend-build skills. It fits anchor 3 (somewhat specific but could still overlap); it is not 4 because the explicit "ANY web design task" claim goes beyond minor overlap, and not 2 because the dominant trigger set is still a clearly defined scroll-effects niche.