Conciseness

The body is mostly efficient and dense with non-obvious specifics (thresholds, timelines, hour budgets), but several sections restate textbook knowledge Claude already has at length — e.g. the full Western Electric rules ('Rule 1: One point beyond 3σ... Rule 4: Fourteen consecutive points alternating up and down'), SPC chart selection (X-bar/R, I-MR, p/np/c/u charts), Cp/Cpk definitions, and the 8D D0-D8 walkthrough. The duplicated 'When to Use' section (lines 9-10 and 230-235) is pure padding. It is above a 2 because most tokens carry domain-specific judgment (red flags, regulatory citations, cost ratios) rather than filler.

Actionability

For an instruction-only skill the guidance is largely concrete: specific thresholds ('If rework cost exceeds 60% of replacement cost, scrap'), concrete CAPA examples ('Add torque verification step at Station 12 with calibrated torque wrench (±2%), documented on traveler checklist WI-4401 Rev C'), template subject lines with variables, and hour budgets for RCA methods. It is not a 5 because some sections are descriptive rather than instructive (the RCA method and regulatory-framework overviews tell you about methods rather than what to do), and there is no worked end-to-end example of applying the frameworks.

Workflow Clarity

Multi-step processes are clearly sequenced with explicit validation checkpoints and feedback loops: the NCR lifecycle mandates 'Containment actions must happen before root cause analysis begins'; the disposition logic is an ordered first-match decision list ('the first path that applies governs the disposition'); and the CAPA effectiveness verification section is a numbered checklist with an explicit error-recovery loop ('If recurrence occurs, the CAPA is not effective — reopen and re-investigate'). Escalation and inspection-adjustment tables add explicit trigger/action/timeline checkpoints.

Progressive Disclosure

The structure is good: all three referenced files exist, are exactly one level deep, and are clearly signaled both inline ('Brief summaries here — see [edge-cases.md](references/edge-cases.md) for full analysis') and in a consolidated 'Additional Resources' section. It falls short of 5 because the SKILL.md itself still carries substantial detail that belongs in the references (full SPC, incoming-inspection, and regulatory knowledge sections could largely live in decision-frameworks.md), and the duplicated closing 'When to Use' section is an organization gap.

Specificity

The description lists several specific capability areas — 'non-conformance investigation, root cause analysis, corrective action, and supplier quality management in regulated manufacturing' — which goes beyond naming the domain. It falls short of anchor 5 because the areas are activity categories rather than crisply enumerated concrete operations, and coverage has gaps (no mention of NCR disposition, CAPA verification, SPC interpretation, or supplier audits).

Completeness

The 'what' is clearly stated ('Codified expertise for quality control, non-conformance investigation, root cause analysis, corrective action, and supplier quality management'), but there is no 'Use when...' clause or equivalent explicit trigger guidance — the rubric caps completeness at 3 in that case. 'In regulated manufacturing' weakly implies a context but does not tell the user when to invoke the skill.

Trigger Term Quality

Good natural keyword coverage: 'quality control', 'non-conformance', 'root cause analysis', 'corrective action', 'supplier quality', 'regulated manufacturing' are all phrases a user in this domain would naturally say. It is not a 5 because common variations users actually use are missing — notably the acronyms NCR, CAPA, SCAR, 8D, and SPC, plus terms like 'defect investigation' and 'complaint handling'.

Distinctiveness Conflict Risk

The regulated-manufacturing quality niche is clear and mostly distinct, with domain-specific triggers like 'non-conformance' and 'supplier quality management'. It is not a 5 because 'root cause analysis' and 'corrective action' are generic phrases that also appear in incident-response, postmortem, and general problem-solving skills, creating minor overlap risk with closely related skills.