Optimizing Multi-Agent Costs on Bedrock: From ~$18 to ~$7 per Diabetes Report Run (Graph vs Swarm Comparison)

The Problem With 5,000 Rows of Blood Sugar Data I've been living with Type 1 diabetes for over 17 years. My mother had it too, along with some of its complications. The disease hasn't changed much — but the tech around it has. I use a MiniMed 780G insulin pump with a Guardian 4 CGM sensor running in SmartGuard auto mode. Every 14 days it produces a report: a ~5,000-row CSV of pump events and CGM readings plus pdf data. I wanted something better — a structured clinical summary that's actually useful for medical staff and for people, that makes sense of patterns. And because I'm a DevOps engineer who can't resist over-engineering things, I decided to benchmark two multi-agent architectures against each other: Graph (sequential pipeline) Swarm (autonomous handoffs) This article covers Graph and Swarm. Architecture 1: The Graph Pipeline Four agents, one after another. Each does its job and passes results to the next: Reader — Ingests the raw CareLink CSV. Extracts CGM glucose readings, ins