The original title is: "131 Tests, 4 Layers: Why My AI Agents Get an Eval Harness First"

Short summary

The author shipped a production AI agent with 131 tests across four evaluation layers after a $0.03/run silent failure nearly cost a client. Traditional unit tests miss emergent behavior, semantic drift across system boundaries, and the long tail of user intent that eval harnesses can catch. The harness runs on Oracle Cloud, routing between Groq and Claude, catching failures at different levels of abstraction before they reach users.

• •Unit tests are blind to semantic mismatches across component boundaries in AI agents
• •A 131-test, 4-layer eval harness catches emergent behavior and semantic drift that unit tests miss
• •Silent failures in production agents compound in cost and trust even at $0.03/run

Generated with AI, which can make mistakes.