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VideoOct 8, 202618 mins

Testing the Nondeterministic: Evals and Experiments for Agent Systems

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Session Overview

Learn how to reliably test and improve non-deterministic AI systems using automated evals and experimentation frameworks.

In this talk, Felipe Perez, a member of the technical staff at OpenAI, walks through how they built an internal enterprise agent platform and evaluation harness. Discover how to move beyond simple question-and-answer benchmarks to multi-turn evaluations, test against prompt injections and tool failures, and use A/B-style statistical testing to ship agent improvements without causing regressions.

What You'll Learn

  • Agent anatomy: Tracking how prompts, policies, tools, and untrusted inputs impact agent context
  • Multi-turn evaluations: Testing real production workflows with deterministic checks and LLM-as-a-judge graders
  • In-code evals: Writing unit tests for tools and faking trajectories to catch prompt injection vulnerabilities
  • Experimentation loops: Running statistical tests over diverse task sets to balance safety, latency, and cost trade-offs

Chapters

  • 00:00 — Introduction & OpenAI's agent platform
  • 03:30 — Why test non-deterministic agents?
  • 06:12 — Multi-turn evals, simulated tools & graders
  • 10:05 — Writing in-code evals & prompt injection tests
  • 13:28 — Running A/B experiments & statistical analysis
  • 17:12 — Building your golden dataset & next steps

About Speaker

Felipe Perez

Felipe Perez Felipe Perez is a Member of Technical Staff at OpenAI, where he builds reliable AI agents, connectors, and high-trust products. Previously, he spent more than four years at Meta working on VR, recommendations, and developer infrastructure.