Conciseness

The body earns most of its length — Meta's delivery mechanics (marginal efficiency, learning-phase event thresholds) are non-obvious domain knowledge Claude does not already have — but each mechanic is explained twice: Learning Phase appears in Phase 2 and again in 'Reference: Domain Concepts', with Auction Overlap, Pacing, and Fluctuation thresholds ("3+ days", "20–30%", "≥50%") duplicated verbatim across Phase 3 and the reference section. Mostly efficient with clear tightening opportunities, matching the 3 anchor rather than 4.

Actionability

Highly actionable for an instruction-only skill: decision tables (evaluation level by campaign setup, relevance-ranking actions, fluctuation verdicts), numeric thresholds, an exact eight-part report template, and a mandatory raw-to-display metric rename table. Minor gaps keep it below 5 — "time-series the segment's CPA" gives no method, and "Live data via your existing Meta Marketing API connection" lacks endpoint specifics.

Workflow Clarity

Phases 0–5 are clearly sequenced with explicit per-phase outputs ("Output for this phase: State the evaluation level explicitly"), a learning-state gate before any judgment, and a Phase 4 verification loop ("If a performance finding can't be restated in marginal/system-mechanics terms, it's probably noise — drop it") plus confidence rules for missing evidence. This matches the 5 anchor: explicit checkpoints, a feedback loop, and checklists.

Progressive Disclosure

The single bundle reference (references/customer-journey-coverage.md, verified to exist) is well-signaled in two places with scoped instructions ("For account audits, full-funnel reviews... read and apply") and is one level deep with no nested references. The inlined 'Reference: Domain Concepts' section, which largely duplicates Phase 3 lens content, is content that arguably belongs in a separate file — good structure with a minor organization gap, matching 4.

Specificity

The description lists multiple concrete capabilities — "Diagnose Meta Ads campaign performance and account gaps", account audits, full-funnel gap analysis, and producing recommendations — and grounds them in six named system mechanics (Breakdown Effect, Learning Phase, Auction Overlap, Pacing, Creative Fatigue, customer-journey coverage). This matches the 5 anchor's comprehensive multi-action coverage rather than 4, which reserves minor gaps.

Completeness

Explicitly answers both questions: what it does ("Diagnose Meta Ads campaign performance and account gaps using Meta's actual system mechanics...") and when to use it ("Use for performance diagnosis, account audits, full-funnel or TOF/MOF/BOF gap analysis, deciding what to test or create next...") with concrete trigger scenarios. This is a direct match for the 5 anchor.

Trigger Term Quality

Includes natural phrases users would say such as "Meta Ads campaign performance", "account audits", "full-funnel or TOF/MOF/BOF gap analysis", and "what to test or create next". A few common variations are missing (e.g. "CPA", "ROAS", "Facebook ads", "ad set") and there are no file-extension-style or synonym completions, so it sits at good-but-not-comprehensive coverage.

Distinctiveness Conflict Risk

"Diagnose Meta Ads" plus platform-specific mechanics terms form a clear niche with distinct triggers, but generic phrases like "performance diagnosis" and "account audits" leave minor overlap risk with sibling ad-analysis skills (e.g. a multi-platform campaign analyzer). Distinct enough for 4, not the minimal-conflict 5.