The PM who hands engineers a functional prototype instead of a PRD is playing a different game. Most PMs at top AI companies still communicate in documents. A PRD describes what should be built. An engineer interprets it, estimates it, queues it, builds it. Somewhere in that chain, the original intent degrades. The PM waits. The engineer guesses. The new version: PM uses Codex to build to 70-80% completion. Engineers take the final mile. No spec interpretation. No intent degradation. The…