shape
Shape
Shaping decides what, how we will know, the one-way doors, and, when the change warrants it, the shape of the code; the rest of how to build it belongs to delivery. The result is one short spec, accepted by the human, that holds or points to everything an agent needs to deliver it without asking again.
Write in the user's language, and write every message the human must answer or act on with writing-for-people.
Roles
The human decides the problem, the scope, the examples that define success, and every cut. You settle facts: read the code, issues, data, and history; run experiments; prepare options. A question whose answer you could observe is yours, not the human's, and so is a value the outcome implies, such as a retention period or a size cap: choose it and give its reason in one line.