Conciseness

The body is dense and mostly authoritative task-specific guidance, but at ~18KB it repeats material across sections (procedure restates the three-part structure; Invocation Behavior restates the procedure; Required Evaluation Criteria restates earlier rules) and includes some explanation Claude does not need (e.g., ISO/IEC 25010 glossing); it is above 3 because the bulk is genuinely task-specific rather than generic concept padding, but not 5 because several sections could be trimmed.

Actionability

Provides a concrete 0-10 anchor rubric, an exact three-part output format with a per-finding field template, a worked mini-example pairing scores with code evidence and remediation, and a pattern-tag table mapping code observations to FIASSE principles — copy-paste-ready guidance covering the common cases; there is no higher anchor.

Workflow Clarity

The procedure (scope → inspect → score → compute → assemble) is clearly sequenced with an explicit output contract and implicit quality checks via the Anti-Patterns section; it is not 5 because there are no explicit validate-then-retry feedback loops, but those are not required for a non-destructive analysis task so 4 fits rather than 3.

Progressive Disclosure

References (plays/securability-engineering-review.md, templates/finding.md, templates/report.md, data/fiasse/SA.*.md, data/asvs/) are clearly signaled and one level deep, and the inlined rubric is justified by the skill's stated 'authoritative' role; it is not 5 because the referenced bundle files could not be verified to exist in the provided workspace and a large amount of material is inlined rather than split out.

Specificity

Lists multiple concrete scoring/reporting actions — '0-10 per attribute', 'equal-weighted pillars', 'evidence-backed strengths and weaknesses', 'prioritized recommendations', '50-item checklist appendix' — giving comprehensive coverage; it is not the level below (4) because coverage is broad rather than having minor gaps, and there is no higher anchor.

Completeness

Explicitly answers both what (score codebase/MR against the FIASSE SSEM model and produce a structured scorecard) and when ('Trigger on ...'); the explicit 'Use when'-equivalent clause pushes it past 4, and there is no higher anchor.

Trigger Term Quality

Comprehensive natural trigger phrases including synonyms and phrasings that do not name SSEM — 'review/score/audit securability', 'SSEM scorecard', 'where would I start hardening this?', 'is this audit-ready?', 'security posture baseline'; level 4 (a few natural terms missing) is too low given the breadth.

Distinctiveness Conflict Risk

Clear niche (SSEM securability scoring) with explicit disambiguation ('For requirements use prd-securability-enhancement; for new code use securability-engineering') minimizing conflict risk; below 5 would imply residual overlap that the disambiguation already resolves.