Arena analyzes 26,000 Agent sessions: costs are 260% higher without caching
Arena.ai analyzed more than 26,000 Agent Arena sessions between September 12 and October 23, 2026, covering 30 agents and 13 labs. If all cached tokens were billed at the model's full input price, the cost of tasks sent to its top ten agents would become 3.6 times higher (260% higher); a typical Claude Fable 5.1 task currently costs $7.44, versus $27 without caching. In the sample, a single cache miss increases a typical task's bill by 5%.
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Based on measured data from 26,000 Agent sessions, the actual impact of caching on agent task costs was quantified.
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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.