Your agent would cost 260% more without the cache. We analyzed +26K Agent Arena sessions from September 12 to October 23, 2026, spanning 30 agents and 13 labs. Caching dramatically changes the economics of a typical task. If every cached token were instead billed at the model's full input price, a task sent to one of Agent Arena's top-10 agents would cost 3.6x as much (260% more). The savings become especially tangible for leading models. A typical Claude Fable 5.1 task costs $7.44 today; without caching, it would cost $27. Even a coffee break can carry a hidden price: if your cache expires while you’re away, the agent may have to resend the entire conversation at full input price. In our Agent Arena sample, a single cache invalidation translated to a 5% higher bill for a typical task. Read more findings from our analysis of the hidden AI price war in the article below.