Who Should Grade Your AI? Rules vs LLM Judges vs Humans

The Real Question Is Not: Which Grader Is Smartest?

When teams begin building AI evaluations, it is tempting to reach for an LLM-as-a-judge because it can read almost anything and return a score. That flexibility is useful, but it can also hide a simpler option.

Suppose an agent is asked to process a refund. The final response says, "Your refund has been completed." You could ask another LLM whether that answer sounds correct. A better grader is to check the transaction state in the database or test environment. The database is closer to ground truth than the prose.