Eval harness: meaning, examples, and expert terminology.

Plain meaning

Runs repeatable scenarios against an AI agent so behavior can be measured instead of judged by vibes.

Aliases

evaluation harness, agent evals, AI agent evaluation

People usually say

• automatically test my ai agent
• test my ai agent
• evaluate my ai agent
• agent keeps doing same mistake
• keeps doing same mistake
• breaks on similar tasks later

Experts usually say

Eval harness, Golden tests, Judge model, Regression set

Use it when

Your rough ask sounds like: automatically test my ai agent, test my ai agent, evaluate my ai agent. The term gives your coding agent a clearer problem shape.

When not to use it

Do not use this term as a request for a quick screen fix. Use it when the system needs explicit state, rules, failures, or recovery behavior.

Prompt upgrade

Weak ask: Fix this automatically test my ai agent flow.

Exact Terms ask: Build an eval harness with representative tasks, expected outcomes, rubrics, traces, and regression checks.

Architecture prompt

Audit this workflow for Eval harness and related concerns: Golden tests, Judge model, Regression set. Return states, rules, failure modes, and recovery behavior before code.

Implementation prompt

Implement Eval harness for this app flow. Include data ownership, edge cases, fallback behavior, and acceptance tests.

Test prompt

Create tests that prove Eval harness works across refresh, retry, back/next movement, partial failure, and return visits.

What goes wrong

Asking for code before defining states, transitions, persistence, and failure behavior.

Better move

Use Eval harness with the related vocabulary trail: Golden tests, Judge model, Regression set.

Turn feedback into vocabulary

If this page almost names your problem but misses the exact term, send the rough phrase and the term you expected. Accepted feedback becomes a better trigger, explanation, comparison page, or new term.