Left of the Loop: The PO is Dead, Long Live the PO

When I wrote about shifting the engineering process left — spec sessions, autonomous agents, humans reviewing output rather than writing code — a question kept coming up. Where does the Product Owner fit in all of this? It’s the right question. And I think the answer is more interesting than “the PO disappears.” Let’s start with acceptance criteria. We invented them to bridge a gap. The team needed to know when something was done. The PO needed confidence that what got built matched the intent. Acceptance criteria were the contract between the two. But if the Spec Session is where intent gets defined — by the whole team, together, before the agent runs — that gap closes. What the team agreed on in the room is the definition of done. The spec is the acceptance criteria. You don’t need a separate validation step because the planning and the agreement happened at the same time. The tighter the loop, the less ceremony you need around it. There’s a caveat though. The spec is a necessary contract. It’s not a sufficient one. Simon Martinelli’s work on the AI Unified Process validates the spec-driven approach technically. But his model is about the artifact — requirements at the center, AI generating everything else from them. How the team actually builds shared understanding before the spec exists isn’t something it addresses. That’s not a criticism. It’s just a different question. A spec written after a real Spec Session — where the team worked through edge cases together, disagreed, got to resolution — is different from a spec written by one person and signed off asynchronously. Same artifact. Different quality of shared understanding. That distinction matters when the agent hits an edge case the spec didn’t anticipate. So what’s actually left for a dedicated PO? Two things. And they’re very different. The first is product thinking — challenging intent, representing user needs, asking why before the agent runs with something. That’s valuable. But it doesn’t require a ded