How do I write a product brief?
Name the user, the problem, the decision the product helps them make, what the product will and will not do, and how you'll know it's working.
The five sections
User. Problem. Decision moment. Scope (what's in and explicitly out). Success signals.
Why short briefs beat long ones
A two-page brief everyone reads beats a 20-page brief no one finishes. Length is not the deliverable; alignment is.