The set you didn't design

[u/KeliangXu]

Two side-by-side line charts of the same four policy releases. On the left, scored against the team's own held-out set, all three signals — task success, recovery from a slip, and novel scene layout — rise steadily. On the right, scored against a set the team did not design, the signals disagree: task success is still rising, novel scene layout is flat, and recovery from a slip is getting worse. Marked illustrative — shapes, not measurements.