Agent Arena finds AI agents read about 93 tokens for every one they write

An Arena.ai analysis of more than 26,000 agent sessions shows re-reading context, not generating answers, drives most token usage AI agents are mostly readers. A new analysis from Arena.ai’s Agent Arena platform found that top-performing agents process about 93 input tokens for every single token they generate. The finding matters because it changes where the money goes. If agents spend most of their budget re-reading context, the price of that re-reading becomes the most important number on the invoice. What Agent Arena measured The study covered more than 26,000 sessions involving 30 AI agents from 13 labs. The data window ran from September 12 to October 23, 2026. The headline ratio applies to top-performing agents. For every output token, they consume roughly 93 cached or re-read input tokens. Re-reads are context the model has already seen. That means earlier instructions, prior steps, files, and conversation history that get fed back into the model as an agent works through a task. According to the analysis, those re-reads made up 86% to 96% of total token usage. The actual output, meaning the text or code the agent produces, accounted for only about 1% to 2%. That pattern fo...