Conciseness

No tokens are spent teaching Claude things it already knows, but the core "prove the one fact, don't trust a convincing writeup" message is restated across Mindset, "Don't trust your own writeup", Verification, Step 5, "What to hand back", and six NEVER/WHY pairs that largely restate the steps above them; the porting blockquote is also long. Mostly efficient content with genuine instruction throughout, but it could be tightened significantly — below anchor 4, above 2 since there is no concept-explanation filler.

Actionability

An instruction-only skill whose guidance is concrete: a five-rung "how sure are you" ladder, an exact multi-agent panel spec (sonnet/high, opus/xhigh, sonnet/max, fable/high with merge rules), a named deliverable format, and case-by-case troubleshooting. Minor gaps keep it below 5 — there is no example proof script or sample writeup to anchor what Step 5's output should look like.

Workflow Clarity

Six clearly sequenced steps with an explicit validation gate ("Before replying, run the same check step 5 already calls for: confirm the one safety fact is either proven... or explicitly marked unproven"), error-recovery feedback in Troubleshooting ("report exactly what happened; it may be the actual answer"), and a deliverable checklist in "What to hand back". This is a review skill, so the destructive/batch cap does not apply.

Progressive Disclosure

No bundle files exist, and the single ~135-line file is organized into clear, navigable sections covering distinct phases. Minor gaps: the long porting-notes blockquote and the Common Failure Modes section are inline material that could live in a separate reference file, and at this length it exceeds the under-50-line simple-skill case that would earn a 5 on organization alone.

Specificity

The description names its domain (pre-ship change review) and two concrete, well-scoped actions: "Find what a change could break somewhere else before it ships, beyond the diff" and "prove the one fact it's safe because of by running real code instead of writing it up". It is above anchor 3 because both actions are specific and vividly scoped rather than generic, but below anchor 5 because only two actions are listed — coverage of the caller-sweep and risk-reporting work is implied rather than spelled out.

Completeness

It explicitly answers both questions: what ("Find what a change could break somewhere else before it ships... prove the one fact it's safe because of by running real code") and when ("Use for 'blast radius of X', 'what could this break', or reviewing a small diff you don't trust. Triggers: ..."), matching the anchor-5 example structure of concrete what plus explicit trigger phrases.

Trigger Term Quality

It lists comprehensive natural trigger phrases users would actually say: "blast radius of X, what could this break, is this change safe, review this diff, what am I missing in this change", covering multiple synonyms and phrasing variations of the same need with no obvious common term missing.

Distinctiveness Conflict Risk

"DO NOT use for explaining how existing code works (use how instead) or investigating why it was built that way (use why instead)" explicitly de-conflicts its two closest sibling skills, and "blast radius" is a distinctive niche phrase — minimal risk of triggering for the wrong skill.