A strong product manager still collects screens, flows, and polish because that is what “knowing a lot” used to look like: a dense grid of features a human could see and tap.
A wise product manager, in an agentic world, cares less about that surface and more about what actually follows from the system acting and what does not. When software had to be operated, a pretty interface was a reasonable proxy for value; it was how people found the knowledge you had packed in.
However, agents invert that. They do not need a gallery of controls to prove competence. They need a correct model of consequences: which action produces the outcome, which assumption is not worth taking, which extra capability is noise.
The product is no longer the interface that displays knowledge. It is the chain that runs from intent to result and the discipline to cut every branch that does not follow.