Builders need clarity on what to build and which things matter the most.
So we need to make sure they have simple listed priorities, and clear requirements so the team can plan and do the work. We’re not aiming for perfection. That isn’t possible. Instead we describe and explain any uncertainty up front.
While the team is working inside an iteration, priorities should stay reasonably stable so the builders can finish without constant interruptions. And outside the iteration, the priorities can change.