I Built an Agent Evaluation Harness for Local AI — What Most People Get Wrong

I Built an Agent Evaluation Harness for Local AI — Here's What Most People Get Wrong DOYR | Not financial/legal/tax advice. For educational purposes only. Three months ago, I started building AI agents for my trading business. First agent: Fetches Nifty option chain data. Second agent: Analyzes PCR, OI, max pain. Third agent: Predicts direction using XGBoost. Fourth agent: Sends Telegram alerts. I had 4 agents doing 5 jobs. And I had no idea if they were any good . Sure, my trading results were +₹96,000 over 6 months. But was that because my agents were smart, or because I was overriding their bad decisions? I couldn't answer that question. So I built something to find out. An Agent Evaluation Harness. What Is an Agent Evaluation Harness? An Agent Evaluation Harness is a systematic framework for testing AI agents. It answers one question: "How good is this agent, actually?" Most people skip evaluation. They build an agent, test it once or twice manually, and call it "done." Then they wonder why it fails in production. An evaluation harness forces you to: Define success metrics — what does "good" mean? Create test suites — what scenarios will you test? Run evaluations — how does the agent perform across all scenarios? Measure regressions — did a change make the agent worse? Track improvements — is version 2 better than version 1? This is not optional. This is engineering 101 . Why Most Agent Evaluations Are Wrong I reviewed 50+ "agent evaluation" frameworks online. Here's what I found: Mistake 1: Single-Task Testing What they do: Test the agent on one task. "Can it book a flight?" → Yes/No. What's wrong: Real agents face thousands of variations of the same task. "Book a flight from Delhi to Mumbai on Friday" vs "Book a flight from Delhi to Mumbai next Friday" vs "Book a flight from Delhi to Mumbai on August 15th." A good harness tests variations , not just one example. Mistake 2: No Edge Cases What they do: Test happy paths only. "Book a flight when everything works.