๐Ÿ“… April 14, 2026โฑ 7 min readโœ๏ธ MoltBot Engineering
EvaluationLLM TestingQuality

LLM Evaluation: How to Test AI Agents Before They Go Live

Most LLM failures in production are preventable with proper pre-deployment testing. The challenge: LLM outputs are non-deterministic and hard to assert. Here's the evaluation stack that catches failures before your users do.

The teams that deploy reliable AI agents aren't lucky โ€” they have evaluation pipelines. Building evals is the highest-leverage investment a team can make before going to production, and it's also the most skipped step.

Five layers of the evaluation stack

1. Golden Dataset Tests

A curated set of 50โ€“200 input/output pairs representing the intended behavior of your agent. Run automatically on every change. Outputs are scored by format compliance, key phrase presence, and LLM-as-judge evaluation. Your production safety net โ€” start building it on day one.

2. Automated Assertion Testing

Rule-based assertions over LLM outputs: required JSON keys present, values within valid ranges, no PII patterns in outputs, no prohibited content. Runs in milliseconds โ€” catches structural failures that deterministic tests can identify without LLM overhead.

3. LLM-as-Judge Evaluation

Use a strong model (GPT-4o, Claude 3.7) to rate outputs on task-specific rubrics: correctness, helpfulness, tone, completeness. Correlates well with human ratings at scale. Define rubrics carefully โ€” vague criteria produce noisy scores.

4. Human Review Sampling

Sample 2โ€“5% of production outputs weekly for human review. Captures failures that automated tests miss โ€” nuanced errors, cultural issues, off-brand responses. Essential for high-stakes applications and for continuously improving your golden dataset.

5. Regression Testing on Model Updates

Every model version update (including provider-side silent updates) should trigger a full regression run. Models frequently regress on specific behaviors after updates โ€” without regression testing, you discover this from user complaints instead of your test suite.

Built-in evaluation on MoltBot

Golden datasets, assertion tests, LLM-judge scoring, regression runs โ€” automated. 14-day free trial.

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