2 min lesson
Regression detection frameworks
Connect "A detection framework has two halves that get confused in interviews" to the decision you would make.
Step 1 of 3
The reliability mandate at Cursor lives or dies on one question: do you find a regression from a screenshot a user posts or from your own alert that fired twenty minutes after the deploy? This section is about building the second world.
A detection framework has two halves that get confused in interviews. Pre-deploy catches the regression before it reaches everyone, on a slice of traffic you control. Post-deploy catches what slipped through, on the live time series of latency, error rate and agent success. You need both, because the canary only sees a sample and the live series sees everyone.