A hydrant-flow model is ready for the city. Testers will send only a small subset of live requests to the new model and watch latency, accuracy, and error rate before a full rollout. What should they name that activity?

Sending only a small subset of live hydrant requests to the new model and watching latency, accuracy, and error rate before a full rollout is canary testing. The small slice is live, so this is not shadow testing. Installability testing of the toolkit and a closet-versus-pier back-to-back check are different activities.