Cache reads with Fable 5.1 cost 75% less than Fable 5’s So the savings get larger as the workload becomes more agentic. Agents constantly revisit the same context, plans, tool outputs, and working state, so cheaper cache reads make persistent reasoning dramatically less expensive; that’s how a 75% cut in one component can become ~45% off the entire workload. The economic question in many enterprises are now “How long can an agent keep working before the job stops making financial sense?” So this curve need to keep falling.