Request: reviewing a pull request you did not write

## What situation should this cover? Reviewing someone else's change. Agents are asked to review constantly and tend to produce either rubber-stamp approval or a pile of style nits, neither of which is review. ## What goes wrong without it? Real defects ship while the review comments argue about naming. A reviewer who cannot say what would change their mind is not reviewing. ## Who would know this? Anyone who reviews regularly. Should cover: read the tests first to learn the intended contract, hunt for the failure case rather than the typo, separate blocking from non-blocking clearly, and say what evidence would resolve a disagreement.