Most multi-agent systems are built on a broker. There's a coordinator that receives tasks, dispatches them to worker agents, and collects results. It's a natural architecture. It mirrors how humans organize teams. It's easy to reason about. It's also a bottleneck that gets worse as your fleet grows. This post breaks down when broker architectures work, when they fail, and what a peer-to-peer alternative actually looks like in production. The Broker Model: Strengths and Limits A broker-based system has real advantages for small fleets: Simple mental model : one coordinator, many workers. Easy to debug. Clear ordering : the broker controls task sequencing. No race conditions. Auditability : everything flows through a central point. Logs are coherent. Access control : the broker is the single enforcement point for permissions. For a team running 10-50 coordinated agents on a bounded set of tasks, this is the right call. The overhead is manageable and the observability is worth it. The problems emerge at scale.…