The prompt set is the asset
Tracking rankings for keywords made sense when people typed keywords. They now type sentences, and the sentence list is what you should be maintaining.
A keyword is a fragment. A prompt is a whole decision: budget, constraint, use case and objection in one sentence. Two prompts that share every keyword can produce completely different brand lists, because the constraint is what the assistant actually answers.
Build it from objections
Start with the questions your support inbox already answers fifty times a week. Add the comparisons your sales calls end on. Add the constraints that disqualify you, because assistants answer those too and you want to know what they say. Thirty to eighty prompts covers most categories.
Then treat the list as a living asset. Re-run it weekly, watch the names move, and attach every movement to a page. Content strategy stops being a guess the moment the prompt set exists.