Plum

As a cost tool in that run, yes: DeepSeek tasks came out 17% more expensive on average and Fable was a wash. If context length is your constraint rather than money, maybe not.

The RTK result makes sense once you look at where the tokens were. Terminal output was about 7% of Fable's input tokens, and later turns read it back from cache at a tenth of the price. Shrinking a small, mostly cached slice barely moves the bill, and changing what the agent sees can add turns.