A real workload analysis shows headroom, rtk, and caveman reduce token costs by 2.8%, 0.5%, and 0.4% respectively, totaling 3.7% of baseline spending. However, savings are limited by payload diversity, with most traffic being plain text or source code, and the tools only compress structured outputs. Most cost reduction occurs on the cheapest token stream—cache reads—while the tools do not affect prompt caching or output costs, and coverage gaps exist, especially for rtk.