Your question is Primary vs Guardrail 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 are reviewing an A/B test for a product change intended to improve a key conversion outcome. The team agrees the experiment needs one main success metric, but there is debate about which other metrics should be monitored so the change does not improve one outcome while harming the overall user experience.
What is the difference between a primary metric and a guardrail metric in an experiment? How would you explain the role each one plays in deciding whether to ship a change?