Can the Product agent write a PRD from scratch? Yes. A PRD has a problem statement, quantified success metrics (it rejects “improve user experience” without a measurable baseline), explicit non-goals to protect scope, user stories, open questions and dependencies. Every PRD needs metrics engineering can verify after launch, and Product flags any spec where success is undefined before it hands the PRD over. You can ask for the version aimed at engineering, a board presentation or customers; each is structured differently.