Results recorded at `benchmarks/RESULTS.md`. 

Summary: The SDK path delivers **75.6% faster warm calls**, **66.8% faster cold starts**, and **64.5% faster multi-turn** with dramatically lower variance. The only regression is batch (+12.1%) due to single-client serialization — addressable with client pooling in a follow-up. Per the plan's decision criteria (>20% warm call improvement → make SDK default), the data supports promoting the SDK path.