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Evaluation harness

LLM evaluation is how you know a model actually does the job on your own data, before it ships and every time something about it changes afterward.

What it controls

Evaluation runs a model, or several models, against tasks and data that represent your own use case, not a generic benchmark, and scores the results against criteria you define. It runs before launch, to decide whether a model is good enough and which one to use, and continuously afterward, to catch the moment a model update, a prompt change, or a data shift makes an answer worse.

Why it matters

A model that scores well on a public benchmark can still perform poorly on your own documents, your own terminology, or your own edge cases. And a model that works well today can get quietly worse after a provider update, a prompt tweak, or a change in the data it's working from, with nobody noticing until a customer does. Evaluation turns that into something you measure on a schedule instead of something you find out about after the fact.

What good looks like

  • Evaluation runs against your own tasks and data, not just a public benchmark
  • A clear, repeatable scoring method so results from different models or dates are comparable
  • Regression checks run whenever a model, prompt or data source changes, not only once at launch
  • Evaluation results feed back into which model gets routed to which task

How it fits with the other harnesses

Evaluation is what makes Model routing a decision instead of a guess: you route to the model that actually scores best on your tasks, and you know when that stops being true. It also gives Reliability something concrete to watch for, a quality regression, alongside outright failures like timeouts.

In practice

Real patterns on the Resources page that lean on this harness:

See all use cases

Frequently asked questions

How is this different from a public model leaderboard?

A leaderboard tells you how a model performs on generic, public tasks. Evaluation here runs on your own data and your own definition of a good answer, which is what actually predicts how a model will perform for you.

Does evaluation only happen before launch?

No. The same checks run continuously, so a regression from a model update, a prompt change, or a shift in your own data gets caught instead of discovered by a customer.

Who defines what counts as a good answer?

Your own team sets the scoring criteria for your own tasks. Zapper Edge runs the evaluation harness against criteria you define; it doesn't impose a generic standard of correctness.

Questions about your AI rollout?

Talk to us about which harnesses fit your models and data.