AI Agent Accuracy Benchmarks: What the Numbers Actually Mean

Every AI agent vendor claims best-in-class accuracy, but the numbers are rarely apples-to-apples. Task completion rate measures whether the agent finished the task — not whether it finished it correctly. Resolution rate measures user satisfaction, not objective correctness. Hallucination rate is the metric that matters most for knowledge-intensive tasks — how often does the agent confidently state something false. To benchmark fairly, you need a held-out test set from your own data, not vendor-provided demos. Run 100 real queries, have humans score each response 1-5, and compute average quality score. Track false positives (escalations that did not need to be escalated) and false negatives (agent failures that should have escalated). A 90% task completion rate sounds impressive until you realize 10% failure on 10,000 daily interactions means 1,000 frustrated users per day.