Great paper from AWS. I use a similar setup where an agent orchestrator sits on top of a multi-agent system. (bookmark it) This work introduces one of the many approaches available to manage compound LLM systems. Compound LLM systems usually solve coordination by adding a higher-level model. That meta-agent reads worker outputs, writes the final answer, allocates later calls and decides when to stop, which concentrates three separate control decisions in one opaque, order-sensitive call. UnitBoost investigates whether the manager needs to be generative at all. A task-given unit map turns worker outputs into slot-value proposals, a constrained argmax assembles the output, and slots left unfilled or unsupported become an explicit residual that directs the next round. On three held-out benchmarks it beats the best single candidate chosen with gold labels by 0.060 to 0.195 task-score points, and beats input-matched generative managers by 0.048 to 0.076. Replacing only the management step improves six compound-system configurations. Residual-directed rounds raise FanOutQA cell F1 from 0.4778 to 0.5524. Chat with Paper: academy.dair.ai/papers/unitb…