Nythrex

Glossary · Definition

LLM evals

LLM evals are automated tests for AI behaviour: a set of realistic inputs with expected results, scored on every change to prompts, models or data.

By Nythrex EngineeringUpdated 1 min read

In plain words

Just as unit tests protect code from regressions, evals protect AI features. They tell you whether a new prompt, model version or retrieval tweak made things better or worse — across all your important cases, not just the ones you happened to try.

When it matters to you

  • Before choosing a model
  • On every prompt or model change
  • When a provider releases a new version

Common pitfalls

  • Only synthetic, easy test cases
  • An LLM judge nobody calibrated
  • Reporting quality without cost and latency

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