In a support-classification review, one model labeled full issue text and a second reviewed the same material independently. Their disagreements exposed ambiguous rules and missing categories. A request about buying a service, for example, had to be separated from a question about how an existing feature worked.
We corrected the instructions and repeated the reviewed cases. The models then agreed, including on leaving some cases unclassified. We recorded that as a development regression check. Because the same cases were reused, it was not a blind accuracy test or proof that support staff would agree.
The prototype stayed out of live routing. A good test report names the inputs, who judged them, what changed, and what it cannot yet prove.
From our article How to test an AI agent before your team depends on it.