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AI Agent Evaluation Workflow

Find out whether an AI agent behaves before users do — define what correct means, build test scenarios with expected outputs, catch failures and hallucinations, then regression-test each version.

The problem

An AI agent that looks impressive in a demo is not an agent you can trust in production — the demo never tried the inputs that break it. Agents fail in ways code doesn't: they're non-deterministic, they hallucinate, and a prompt tweak that fixes one case silently breaks three others. 'It worked when I tried it' is not evaluation. Knowing whether an agent behaves means deciding what correct looks like, testing it against real scenarios with expected outputs, catching the failures and inventions, and re-running the whole set every time you change something — so improvement is measured, not hoped for.

Recommended workflow

Each step uses an existing NewPrompt tool, pre-filled by a matching resource. Open the resource to read it, or jump straight into the tool with the inputs ready.

  1. Define what correct behavior means

    Before testing anything, decide what the agent must and must not do — the behaviors that count as success, the ones that count as failure. Anchor the model in a QA mindset so evaluation is measured against criteria, not vibes.

    Outcome The behaviors that count as correct, defined as evaluation criteria.
  2. Build test scenarios with expected outputs

    Turn the criteria into concrete scenarios — the normal cases, the edge cases, the adversarial inputs — each paired with the output a correct agent should produce. A test set with expected outputs is what makes a pass or fail meaningful.

    Outcome A scenario set, each with the expected correct output.
  3. Run the eval and catch failures and hallucinations

    Run the agent against the scenarios and check each result against its expected output — flagging the wrong answers, the made-up facts, and the cases where the agent should have refused but didn't. Failure analysis is the point, not a green count.

    Outcome Failures and hallucinations identified against expected outputs.
  4. Regression-test every version

    Every time you change the prompt, the tools, or the model, re-run the scenario set and diff the results against the last known-good run — so an improvement to one case can't silently regress another.

    Outcome A regression check that catches behavior drift between agent versions.

Expected outcome

An agent you can trust because you tested it — correct behavior defined, a scenario set with expected outputs, failures and hallucinations caught, and a regression check that re-runs on every change — so you ship on evidence the agent behaves, not a demo that happened to work.

Best for

  • Verifying an AI agent behaves before shipping it
  • Catching hallucinations and failure cases an agent demo missed
  • Regression-testing an agent across prompt or model changes

Not for

  • Building the agent's instructions in the first place — use the AI Agent Instruction Workflow
  • Testing deterministic application code — use the AI Test Generation Workflow
  • Reviewing source code for correctness — use the AI Code Review Workflow

FAQ

AI agent evaluation vs AI test generation: what's the difference?

Test generation writes tests for deterministic code, where the same input always returns the same output and a pass is exact. Agent evaluation targets a non-deterministic agent: you define correct behavior, build scenarios with expected outputs, catch hallucinations and wrong refusals, then regression-test each version against the last good run.

Can the AI fully judge its own agent?

It can run scenarios, flag mismatches against expected outputs, and surface likely hallucinations — but the criteria for what counts as correct, and the call on borderline cases, stay yours. The workflow makes evaluation systematic; it doesn't make it fully automatic.

What do you get out of an AI agent evaluation?

You end with four artifacts: a written definition of correct behavior as evaluation criteria, a scenario set each paired with its expected output, a list of caught failures and hallucinations, and a regression check that diffs each version against the last known-good run. Evidence the agent behaves, not a demo.

How to run the AI agent evaluation workflow

Work the four steps in order in your own AI tool: define correct behavior with the role-prompt generator, build scenarios with expected outputs, run the agent and flag failures and hallucinations against those outputs, then regression-test on every change. NewPrompt supplies the prompts and step order; you run each one and own the pass or fail call.

What do I need to evaluate an AI agent?

You need a built AI agent to test, and a clear sense of what it must and must not do — that becomes your evaluation criteria in step one. From there you write scenarios covering normal, edge, and adversarial inputs, each with the correct output. No prior test suite is required; the workflow builds it.

Why does my AI agent evaluation show false positives?

A false positive usually means the expected output was too strict — the agent's answer was acceptable but didn't match your fixed string. Loosen the criteria to judge behavior, not exact wording, and re-run. You own that call: decide whether the mismatch is a real failure or an over-narrow expectation before you fail the case.

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Tip: Each step's resource opens its tool pre-filled — start at step one and carry the output forward.