A typical task for one of Agent Arena's top-10 agents would cost 3.6 times as much without caching

In 26,225 sessions across 30 agents and 13 labs from September 12 to October 23, 2026, Agent Arena estimates a typical task for one of its top-10 agents would cost 3.6 times as much if cached tokens were billed at full input price. A typical Claude Fable 5.1 task would rise from $7.44 to $27 without caching. It says one cache invalidation added about 5% to a typical task's bill in its sample.