Building Conversational Commerce with Multi-Agent Swarms on GCP: A Working Prototype

The post presents HappyDelivery, a working prototype of the previously described three-layer conversational commerce architecture built with LangGraph, Gemini, FastAPI, and Google Cloud. It details an omni-channel ingress service that verifies platform-specific signatures and normalizes payloads before queuing them to Pub/Sub, a Redis session and cart layer, and a LangGraph agent swarm with supervisor, profile, inventory, and transaction specialists using deterministic pricing tools. Live benchmarks and a three-turn simulated shopping flow, plus a five-test automated suite, are reported as verification.