Conciseness

Largely prescriptive spec with complete code — no tutorials on concepts Claude already knows. Minor redundancy keeps it off anchor 5: the single-file/CDN-only rule appears three times (Required CDN Dependencies, Output Spec, Anti-Patterns), the 'derive accent algorithmically' rule appears three times (Q3, Override Pattern, Error Handling), and the CDN URLs are re-listed in the Validation section.

Actionability

The GSAP timelines, mouse-parallax, ScrollTrigger.batch, CDN snippet, exact px/type scales, and error-handling table are copy-paste ready. Two gaps keep it off 5: the validation step ('Run scripts/html_validator.py') and the palette/slug helpers reference scripts that do not exist in the bundle, and '@keyframes floatB { /* different duration + rotation */ }' is placeholder pseudocode rather than executable code.

Workflow Clarity

Dependency-ordered Phase 0 (Q1→Q4) with explicit stop condition ('After Q4, commit and generate'), content extraction, build spec, then a post-generation validation step with a true feedback loop: 'html_validator returns FAIL → Regenerate ONLY the failing sections in one targeted pass; do NOT abandon the file'. Error handling is tabulated. Matches anchor 5's validate→fix→retry pattern.

Progressive Disclosure

The body is well-sectioned and reference links are clearly signaled one level deep (references/brand_system_design.md, gsap_animation_patterns.md, single_file_html_discipline.md), but none of the three reference files or three scripts exist in the bundle — every referenced path is dead, so the disclosure structure cannot actually be navigated. Not anchor 4 ('most content appropriately placed') because the split the skill itself describes is broken; not anchor 2 because the body is well-structured and self-sufficient for the core task.

Specificity

Multiple concrete actions in third person voice: 'Generates a premium single-page HTML landing page with 3D CSS animations, GSAP scroll effects, and mouse-parallax depth', 'Outputs a single self-contained HTML file (Claude Code) or HTML artifact (Claude.ai)', 'Supports configurable brand colors via CSS custom property overrides'. Coverage is comprehensive with no generic filler.

Completeness

Explicitly answers both what ('Generates a premium single-page HTML landing page... Outputs a single self-contained HTML file') and when ('Use whenever the user says...') with concrete trigger phrases. Anchor 5 matches directly; anchor 4 would require the 'when' to be less explicit, which it is not.

Trigger Term Quality

Extensive natural trigger phrases with synonyms: 'landing for X', 'create a landing page', 'build a landing page', 'make a landing page for X', 'I need a web page for Y', 'promotional page', 'product page', 'one-pager', 'web presence', 'sales page' — all phrasings a user would naturally say.

Distinctiveness Conflict Risk

The single self-contained HTML output format is a distinct niche, but the primary triggers ('create a landing page', 'build a landing page') are exactly the phrases a Next.js/conversion-optimized landing page skill would also match; the description itself doesn't differentiate from that sibling (the differentiation lives in metadata/body, not the description). Not the level below: the output-format pin ('single self-contained HTML file') prevents overlap with broad web-building skills.