The 15x Token Tax on Multi-Agent Coordination

Multi-agent systems that coordinate over HTTP serialize context into JSON, send it as request bodies, parse it on the other end, and feed it back into an LLM. Every message carries HTTP headers, content-type negotiations, and authentication tokens. Every coordination step re-transmits the accumulated context of the entire interaction because HTTP is stateless. Measurements show this coordination overhead costs up to 15x more tokens than the actual task content. A three-agent pipeline processing a document: Agent A sends the document + instructions to Agent B (5K tokens). Agent B sends everything + its analysis to Agent C (12K tokens). Agent C sends the full chain back with its contribution (20K tokens). The document was 3K tokens. The coordination overhead was 34K. At scale, 15x token overhead versus 1x is the difference between cost-effective and prohibitively expensive. REST polling is even worse. 98.5% of requests return nothing new. You pay for every empty round trip. Pilot Protoco