The checker

check.mjs proves that a review, or an answer to it, is well-formed, complete and honest. It has no dependencies on purpose: a checker that needs an install is one fewer people run. Every error says what is wrong, what to do, and what leaving it would cause, in one line. Exit code 0 only when nothing is wrong; warnings never fail a run.

The value: the agent never shows you a broken review, and never acts on an answer that doesn't add up.

The modes

Mode	Run it on	What it proves
review	a review	The shape matches the schema; every id is unique; the flow reaches every screen and has no dead ends; diagrams make sense; every code reference exists (with --root); no secrets; nothing left to fill in
feedback	an answers file	Every answer uses the review's words; the totals and gaps are true; no two answers share an id
pair	a review and its answers	The answers belong to this review: every question is there, titles match, choices and approvals echo what was asked
history	a review and earlier answers	Every earlier decision the review quotes (affects) is quoted correctly
followup	the next review, the review, its answers	The next round carries everything left open: every gap, added item, request and unsettled answer, and answers every comment
rounds	a round and all the rounds before it	The whole chain: each round a checked pair, each linked to the one before, nothing dropped
copies	a review and several answer files	Whether two people's answers agree; differences are named, never merged

Add --format json to any mode to get the result as data (each problem with a stable code), for tools and CI.

A few of the rules, and why

• Unanswered is written down. A missing answer would look the same as "never reached them".
• Derived fields must be true. The summary is what people read instead of the data.
• The reviewer can always add an item. The things nobody knew to ask are usually the valuable ones.
• An approval must still be valid when it is used, and must be word for word what was asked.
• Pictures are what they say they are, judged by their own bytes, with size limits.
• Examples need a source, or the page marks them unverified: agents invent convincing examples.

What it does not prove

Who answered, or that they may decide. The files are unsigned; trust comes from how the file travels (your repo, your email, your ticket system).