Introduced on day 52
Regression gate
A pass/fail rule on a frozen evaluation set, overall and per slice, that a release candidate must meet before it can receive traffic.
In detail
Gates are agreed before the run and include floors for slices that carry risk, such as refunds or unanswerable questions, not only an overall rate. Each production failure becomes a new case in the set. A passing gate permits a canary; it does not replace monitoring on live traffic.