Conciseness

The body is dense and operational — numbered plays, a situation→play table, a copy-paste deliverable template — with almost no explanation of concepts Claude already knows, matching the efficient 4 anchor. It is not a 5 because minor content could be trimmed: the six-quote "Receipts" section (~12 lines) duplicates material already in `references/quotes.md`, and per-bullet guest attributions add tokens beyond what the guidance needs.

Actionability

For an instruction-only skill the guidance is fully executable: concrete diagnostic questions capped at 4, exact tactics ("say *try something else*", "export to GitHub (or compress with Repomix)", "add console logs along each step, rerun, paste the full log back"), a complete copy-paste-ready Prototype Brief template, and a 1–5 anchored grading table. This matches the 5 anchor: specific examples cover the common cases.

Workflow Clarity

The sequence is explicit (Step 1 Diagnose → Step 2 Pick the play → Step 3 Run it → Deliverable) with real validation checkpoints: "Done when: a stranger can complete the core journey", a "Stop rule" against brute-forcing infeasible capabilities, success/kill signals in the user-test plan, and a debug loop with revert-and-rethink plus a rules-file lesson as the error-recovery feedback loop. Not 4: checkpoints are explicit at each phase, not merely implied.

Progressive Disclosure

Good structure with one-level-deep, well-signaled references that are real files ("`references/frameworks.md` — every framework in this skill, how to run it"; "`references/quotes.md` — verified quotes with timestamps"), and the operational core is correctly kept inline. It falls short of the 5 anchor because content that belongs in the separate quotes file (the six Receipts quotes) is also inlined, duplicating the bundle rather than cleanly splitting it.

Specificity

The description lists multiple concrete actions with comprehensive coverage — "Turns an idea into a working, user-testable prototype with AI builders (Lovable, v0, Bolt, Replit, Cursor, Claude Code)", "gets you unstuck when the tool breaks", "Produces a Prototype Brief with a build-prompt pack, a debugging log and a user-test plan" — which matches the 5 anchor, but the second-person clause "gets you unstuck" violates the third-person-voice rule ("Processes files", not "You can use this"), reducing the score by 1 per the rubric.

Completeness

It explicitly answers both what ("Turns an idea into a working, user-testable prototype...", "Produces a Prototype Brief...") and when ("Use for 'vibe coding', 'build a prototype'...") with concrete trigger phrases — exactly the 5 anchor. Not 4: the 'when' clause is fully explicit, not merely present.

Trigger Term Quality

Trigger coverage is comprehensive and natural: "'vibe coding', 'build a prototype', 'prototype this feature', 'Lovable prompt', 'my AI builder is stuck', 'prototype instead of a PRD', or 'demo for users'" — these are phrases a user would actually say, with synonyms (prototype/prototype this feature/demo) plus specific tool names. Not below 5: no common variation is obviously missing for this domain.

Distinctiveness Conflict Risk

Clear niche (AI-builder prototyping and debugging) with distinct triggers — "Lovable prompt", "my AI builder is stuck", "vibe coding", "prototype instead of a PRD" — that few other skills would claim, matching the minimal-conflict 5 anchor. Tool names like Lovable, v0 and Bolt further disambiguate.