Review a design doc for the decision it asks you to ratify — not the prose. Catches the expensive-to-reverse mistakes while they are still words: a problem stated as a solution, alternatives that were never really considered, a one-way door taken without noticing it is one, invariants that hold only on the happy path, a contract the design cannot actually keep, and success criteria you could never falsify. Weights scrutiny by reversibility × blast radius and hunts the highest-value target of all — the load-bearing question the doc never asks. Use before a design review meeting, before you +1 an RFC, or when a doc reads well but you can't say why you trust it.
