Prototype acceptance and exception ownership
Define acceptance before the prototype review
Before a code-adjacent prototype becomes a handoff candidate, write the small set of states it must represent, the accessibility checks that matter for the concept, and the engineering owner who can reject the handoff when generated code or dependencies are not reviewable. Record the reviewed states and each pass/fail result in the handoff so engineering can see what was actually checked instead of inferring acceptance from a polished demo.
Keep exceptions owned instead of silently normalizing them
If a prototype intentionally skips a state, accessibility behavior, data constraint, or production dependency, name the owner and follow-up condition in the handoff. Do not let a visually convincing happy path become implied production acceptance.
Re-run acceptance when the prototype materially changes
Bind the handoff record to the exact prototype revision that was reviewed. If screens, states, data assumptions, dependencies, or generated code materially change after review, mark the affected pass/fail evidence stale and rerun those checks before engineering accepts the handoff.