When you deploy an agent to production, one of the hardest questions is whether it’s actually working? The bar isn’t whether it runs. It’s whether it does what the business needs, at scale. Many teams will tell you they can’t really see this. They spot-check outputs, watch latency, and collect user feedback when they can get it. None of that tells you whether the agent finished the user’s task, stayed on topic across a long session, leaked personally identifiable information (PII), or quietly skipped half the steps it was supposed to follow.

Figure 1: Teams usually watch surface signals, but business outcomes are decided by the agent behaviors below the waterline

Agent evaluation solves this problem. What makes this challenging is that a good score on one metric can hide a failure on another. A support agent can resolve every ticket and still expose personal information in its replies. In this case, the agent is failing although it has a high completion rate. To get evaluation right, measure the behaviors that matter for each agent, at the right level of detail.