Start with the problem that has no owner, not the feature that has a champion.
When I scope a 0→1 platform, the first question is always: who is in pain right now, and what are they doing instead? The workaround is the product. If developers are copying API specs into Notion docs and pasting them into prompts, that's not a workflow — that's a gap in the platform I should build.
I define the non-negotiable in week one: the one thing the platform must do for a developer to have a better day. Everything else is deferred. I've learned that 0→1 dies from scope, not from lack of features.
The metric that proves the platform worked is almost never adoption — it's the behaviour change. Did the developer stop doing the manual step? Did the team stop asking the same question twice? That's the only signal worth optimising for at the start.