How to Turn Production Agent Failures into Regression Tests
A practical workflow for capturing an AI agent failure, preserving the evidence, and turning it into reviewed regression coverage.
The useful unit is an attributable failure
A screenshot that says “the agent was wrong” is not yet a regression test. The useful starting point is one attributable interaction: the input, relevant tool or retrieval steps, observable output, expected behavior, and the first point where the execution departed from it.
That evidence can come from an OpenTelemetry trace, a saved run, a provider response, or a carefully reconstructed case. Preserve the identity of the source and redact secrets before it becomes test data.
Separate the symptom from the reusable behavior
Production incidents contain details that should not become permanent fixtures: customer names, account identifiers, timestamps, and incidental wording. The regression case should protect the behavior that matters.
- Symptom: the agent refunded an ineligible order.
- Reusable behavior: require a verified eligibility signal before calling the refund tool.
- Protected evidence: tool name, authorization state, arguments, and final user-facing outcome.
Use a five-step trace-to-gate workflow
- Capture. Save the smallest trace or interaction that proves the failure.
- Explain. Identify whether the failure came from retrieval, model behavior, tool selection, arguments, policy, or execution infrastructure.
- Author. Convert the behavior into a reviewed case with explicit pass criteria and provenance.
- Validate. Prove the case detects the known-bad behavior before claiming it prevents recurrence.
- Gate. Run the affected scope against an immutable baseline and block only on valid evidence.
Do not promote raw production data automatically
A trace can suggest a candidate case, but it should not silently become a release blocker. Human review is where a team confirms the intended behavior, removes customer-specific details, selects the protected slice, and decides whether the example is representative.
Keep invalid runs out of product conclusions
Provider timeouts, parser failures, missing candidates, and broken credentials are execution failures. Preserve them as reliability evidence, but do not quietly score them as product regressions or retry until the result turns green.
Report the whole release tradeoff
A useful gate report covers quality, protected slices, reliability, latency, and cost. If a dimension was not measured, say so. A correct block decision can still be an incomplete handoff when it omits a supplied latency or token-cost increase.
Start with one failure you can reproduce
Do not begin by building a giant benchmark. Choose one expensive or repeated failure, create one reviewed case, prove that the bad version fails and the fixed version passes, then add it to the smallest relevant CI gate.
EvalGate’s trace-to-eval guide and CI guide show the supported workflow.