My agent looked fine — until I gave it an empty list A developer built a free browser-based tool that scores AI agent responses across 20 tasks—10 developer, 5 personal-life, and 5 creator—on four criteria: finished, correct, no fabrication, and no wrong action. The tool uses auto-scoring suggestions that the user confirms, runs without an API key or login, and keeps all data on the page; the developer positions it as a quick first check rather than a CI or production replacement. One sample task tests whether an agent safely handles an empty list when computing an average. I built a small tool to test my own AI agent in 10 minutes, instead of trusting that it "looked right." One test from it: "Handle an empty average." The starting code divides by the list length, so an empty list breaks it. The check is simple: handle an empty list safely, keep the normal average, and explain the empty-list behavior. I ran two answers through it: That is the whole point of the tool. It scores 4 things per task: finished, correct, did not make things up, and took no wrong action. Auto-score suggests, you confirm — so you get speed without handing the judgment to a black box. The tool has 20 tasks: 10 developer, 5 personal-life, and 5 creator. It is free, with no API key, no login, and nothing leaves the page. It is a quick first check, not a CI or production replacement — use it first, then graduate to heavier tools when you need them. Try this one task yourself: https://jefferson999.github.io/agent-reliability--score/ https://jefferson999.github.io/agent-reliability--score/ Paste your agent's answer, see the score, and read what to fix. If your agent passes the empty list, try the other 19.