Conciseness

The body is dense and directive — the recurrence test, confidence classification ladder, symptom-shape filter ("100% failure rules out races; deploy-aligned onset implicates the release"), and blameless framing are judgment Claude would not produce reliably by default, and no space is spent on concepts Claude already knows. It misses the 5 anchor because of trimming opportunities: the ~24-section annotated output template with per-line commentary, the long opt-in "Optional Workflow Integration" section, and a routing boundary that restates the description.

Actionability

As an instruction-only skill the guidance is fully actionable: eight phases each with concrete checklists (e.g., Phase 1's "expected vs actual... first occurrence and frequency (once / intermittent / constant)"), a defined four-level statement classification (Verified Fact / Likely Cause / Possible Cause / Unknown), a copy-paste-ready report template, and a fully worked example with real evidence-based reasoning (deploy-correlated KeyError, ruled-out lockfile hypothesis). Per the rubric's scoring note, absence of code is not penalized when the guidance is this specific.

Workflow Clarity

The eight phases are explicitly sequenced with mandatory/optional marking ("1–4 are mandatory for every RCA; 5–7 deepen the analysis"), scaling guidance ("for a small bug-RCA compress the phases"), and validation checkpoints throughout: hypotheses must carry "confidence, supporting evidence, contradicting evidence... and a validation method" with cheapest-test-first elimination, evidence classification gates every claim, the confidence model blocks silent promotion ("may ship at MEDIUM only with the missing verification named as the first action item"), and the recurrence test is the acceptance criterion for preventive actions. This is the explicit-validation-with-feedback-loops anchor.

Progressive Disclosure

Structure is good: a Read|When reference map, six phase-linked references that all exist in the bundle and are one level deep, and "Read a reference when its phase begins" on-demand loading. It is not the 5 anchor because the "Required packaged policies" section links ten files — `shared/base/*.md` (nine policy modules) and `shared/workflow-contract.md` — that do not exist in the provided bundle, so those references dangle; it is above the 3 anchor because the core navigation (the reference map and in-phase citations) is clear and the inline content is appropriately placed.

Specificity

Lists multiple concrete deliverables — "timeline, causal chain, contributing conditions, corrective actions, and prevention" — under the specific action "Produce a systemic, evidence-based incident RCA/postmortem after a failure", in third person. This matches the comprehensive-coverage anchor; it is not the level below (4) because the action list covers the skill's full output surface, not just several actions with gaps.

Completeness

Explicitly answers both: what — "Produce a systemic, evidence-based incident RCA/postmortem... timeline, causal chain, contributing conditions, corrective actions, and prevention"; when — "Use when recurrence prevention and organizational learning are primary", reinforced by an explicit exclusion ("Do not use as a generic live debugger"). Both are explicit with concrete trigger concepts; a missing/weak when-clause would cap it at 3 and a merely serviceable when at 4, neither of which applies.

Trigger Term Quality

Natural terms users would say are present: "incident RCA/postmortem", "failure", "recurrence prevention", "organizational learning", plus the negative trigger "Do not use as a generic live debugger". It falls short of the 5 anchor because common natural phrasings like the spelled-out "root cause analysis", "outage", and "post-incident review" are absent, while "organizational learning" is more abstract than user-utterable.

Distinctiveness Conflict Risk

It carves a clear niche (post-incident systemic analysis with recurrence prevention) and actively disambiguates the closest rival by saying "Do not use as a generic live debugger", matching the clear-niche/minimal-conflict anchor. It is above the 4 anchor because the negative trigger plus goal-based routing ("recurrence prevention and organizational learning are primary") makes wrong-skill triggering unlikely, not merely minor.