Evaluating an intent classifier: what I check beyond accuracy

I built the intent router that sits at the front of our support agent. It reads what a user typed and decides which pipeline handles it. I tested it on a nice balanced set, got 92 percent accuracy, and shipped it feeling good. Two weeks later the on-call engineer noticed cancellation requests were landing in the billing queue. The fraud-report queue was empty while actual fraud complaints sat in product feedback. And a newer request type that did not exist when we launched was being silently…