AI generates drawing sets in minutes. Nothing checks them. Markup & Validate is the review station for that gap. Redline sheets with familiar markup tools, run a 15-rule AEC standards profile covering title block, sheet numbering, dimensions, schedules, and revision control, then sign off only when the gate is clear. Every finding needs a named reviewer and written evidence. Sign-off stays blocked while anything is open. Export the annotated PDF, review JSON, and CSV record.