Evals (AI Evaluation)
Automated tests that measure how well an AI system performs on representative inputs.
Evals are the unit tests of AI engineering. You collect representative inputs, define what success looks like (an exact answer, a graded quality score, a rubric), and run the system against them. When you change a prompt, model, or pipeline, evals tell you if it got better.
Without evals, AI development is vibes-based you remember what changed and convince yourself it's better. With evals, you can refactor prompts, swap models, and add features with confidence.
Eval tooling matured fast in 2024-2026. LangSmith, Braintrust, Promptfoo, Helicone, Inspect-AI, and the official OpenAI Evals are all options. Most production AI teams treat evals as production-critical infrastructure.