Premortem

Premortem is an optional plan-challenge strategy. It asks one fresh context to identify concrete ways the resolved bead or caller intent could fail before implementation. It is not part of the required RPI sequence and does not authorize readiness. Plan's shared challenge method owns optional exchange, independence and stopping rules. Premortem owns the failure checks below; invoke it when that broader examination is requested.

The first check: who verifies, and are they fresh?

Before any technical risk, test the plan's EVIDENCE SHAPE: for every unit of work, who verifies it, and is the verifying context distinct from the authoring context? A plan whose closure step is "the implementer runs its own tests and closes" contains no independent judgment anywhere — self-graded green is the classic false-done, and it outranks any single technical risk because it silently converts every other failure into a shipped one.