Your question is Design Feature Success Metrics. Take a moment with it on the right.
Talk me through your thinking if you like. When you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes).
You've shipped a new product feature and want a clean way to judge whether it is actually creating value. The team wants one primary success metric, plus guardrails that catch harm to the broader user experience and business.
How would you design the primary metric and guardrails for a new product feature?