Pressure-test an existing plan or design artifact until it is coherent enough for the next workflow step or plainly blocked. Use when the user wants to be grilled on a plan, design doc, PRD, ADR, rollout plan, migration runbook, rolling-wave project shape, or slice contract; when they say "grill me"; or when Codex should interrogate a source-of-truth artifact, inspect code and adjacent docs before asking, auto-answer evidence-backed questions, ask only about conflicts or low-confidence recommendations, edit the original file in place, preserve the artifact's existing format, and keep conclusions, blockers, readiness, and deferred work synchronized in the document.