Evals

Evals are the AI equivalent of unit and integration tests: test cases with expected behavior that grade your prompts, agents, and models. Without evals you can't ship AI changes safely — you're guessing whether the new version is better.

A good eval suite has: a set of representative inputs (drawn from real usage where possible), a graded output for each (sometimes a human grade, sometimes an LLM-as-judge), and a clear pass/fail or score-distribution metric. Run the suite before any prompt or model change.

For operators evaluating AI vendors, ask: "do you run evals, what's in your eval set, how often does the score regress?" Vendors who can answer well are usually shipping more reliable products. Vendors who shrug at the question are not.