The five passes
Pass one: the counts. Every number a page prints against the data it claims to read. Pass two: the links — every route a document mentions must answer. Pass three: the claims — every sentence about automation must name the check that runs it. Pass four: the fixtures — every rule must be proven to fire on a broken input. Pass five: the docs — the files that describe the site must describe the site as it is now.
Why the claims came last and first
The pages were fine through every pass. The claims were not: counts drifted within a batch, a check was described that did not exist, a number was quoted without its frame. The claims are the site's self-portrait, and a self-portrait that flatters is a lie with better lighting.
The method is one sentence: whenever the site says something about itself, find the check that keeps it true — and if there is none, the sentence is the next batch's first item.