What problem does it solve? Green tests do not prove a feature actually works, and a model reviewing its own code shares its blind spots. This Skill closes both gaps before merge: it drives the real application to prove behavior against the spec, and runs a senior code review on a different model than wrote the code. ## Core Features & Use Cases - Runtime verification: The verify mode launches the real app, exercises the changed flow (UI, API, CLI, jobs), and reports pass or fail per behavior and per spec acceptance criterion, with cited evidence for every verdict. - Cross-model code review: The review mode spawns a reviewer subagent on a different model family than the author, ranks findings by severity (Blocker, Major, Minor, Nit), and writes them to docs/reviews/. - Spec conformance gate: When a governing spec exists, it confirms every acceptance criterion is met and every specced surface (page, route, table, migration) was actually built and applied. - Use Case: After finishing a feature branch, run verify to watch the new checkout flow work end to end against its spec, then run review before opening the PR so a fresh model catches correctness, security, and error handling issues in the diff. ## Quick Start Ask the AI to run the check skill in verify mode to prove the current change works against its spec, or in review mode for a fresh-model code review of the diff.