Bayes-Sufficient Compression Is Not Enough: How Does Communication Help Multi-Agent Systems?

The paper introduces a framework called receiver-relative bounded coordination to study when short messages improve multi-agent system decisions versus when raw context is preferable. It finds that even Bayes-sufficient compression can fail when a bounded executor cannot use its surface form, and that sender upgrades help above a receiver-burden threshold under a single-crossing condition. Across six benchmarks, the same Qwen protocol raises ContextBench joint accuracy from 0.633 to 0.775 but lowers ToolSandbox from 0.889 to 0.653.