SheetCheck reads the sheet index and every title block straight out of a drawing-set PDF, then cross-checks them against each other. It catches the quiet mistakes that slip into bid sets, missing sheets, unindexed pages, mis-titled drawings, and sheets bound out of order, before they turn into RFIs and addenda.
Missing, duplicated, unindexed, or out-of-order sheets, verified against the set's own index.
Action: correct the set before issue.
Either a plausible innocent explanation exists (partial volume) or extraction couldn't verify with confidence (unreadable number, possible extraction artifact).
Action: reviewer judgment required.
Advisory only.
Action: awareness, no required fix.
SheetCheck reports, it never corrects. Severity is triage for the reviewer who owns the fix. The judgment and the stamp stay with the human.