131 Tests, 4 Layers: Why My AI Agents Get an Eval Harness First

The author shares a cautionary tale about the importance of rigorous testing in AI agent development. After a costly failure from a seemingly functional but flawed agent, they implemented an evaluation harness with 131 tests before adding new features. This proactive approach highlights the limitations of traditional unit tests in complex multi-agent systems, underscoring the necessity of comprehensive testing to avoid silent failures and maintain client trust. The story emphasizes that thorough testing isn't just a best practice but a crucial safeguard in AI development.