Qinnan Cai

Role-factorized hierarchical search agents: delegation capacity matters more than execution

A new arXiv paper investigates how model capacity should be distributed across roles in multi-agent search systems, factorizing hierarchical search into delegation, execution, and answer generation roles. Controlled sweeps across five multi-hop QA benchmarks find that scaling the delegation backbone improves exact match by ~11 points while scaling execution sub-agents yields only ~2.6 points, identifying task decomposition as the primary bottleneck. A 1.7B-parameter executor trained via trajectory distillation matches frontier sub-agent accuracy while using 37% fewer tokens, advancing the efficiency Pareto frontier. The results offer a concrete design recipe: concentrate capacity at delegation and downsize execution.