MCP vs A2A, Implemented Side by Side: Lower Coordination Complexity Versus Native Stateful Multi-Turn Support

arXiv 2607.23884·medium signalXBlueskyLinkedInCopy link

An implementation-grounded comparison (arXiv 2607.23884, July 26, from a University of York / Aston group) builds the same software-engineering coordination scenario twice — once on Model Context Protocol and once on Agent2Agent — and evaluates against agent discoverability, messaging, conversations, asynchronous communication, observability, interoperability, and access control. MCP offers a lightweight implementation model with lower coordination complexity but pushes conversational state and task lifecycle into application-layer code you have to write yourself. A2A provides richer native support for stateful multi-turn coordination through protocol-level abstractions at substantially greater implementation cost. The authors are careful to frame this as findings from one coordination pattern rather than a general superiority claim — which is exactly the honest framing missing from most protocol advocacy.