Decoder. plain-English AI glossary

Evals

● Core“ee-vals”

Also called Evaluations

Tests for AI — a repeatable way to check whether the model actually got better or just feels like it did.

Think of it like

A unit-test suite, but for judgment instead of code.

Example

Before shipping a new prompt, a team runs it against 500 saved questions and counts how many it nails.

How it actually works

They range from exact-match graders to “LLM-as-judge” setups where one model scores another. The hard part is never running them — it is writing eval sets that reflect what real users actually do, not what is easy to grade.

For product teams

A regression suite for quality — proof a change actually moved the metric before you ship.

For engineers

Automated graders (exact-match, rubric, or LLM-as-judge) scoring output over a fixed dataset.

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