Building a Production AI Agent in Spring Boot: Streaming Responses with SSE (Part 3)

A software engineer developed an e-commerce AI assistant using Spring Boot and Model Context Protocol (MCP) to connect internal tools. Initial challenges included a nine-second silent wait during complex tool calls and scalability issues with stateful SSE transport under load. These problems, including WebSocket drops and file descriptor limits, hindered performance behind load balancers. Consequently, as of July 28, 2026, MCP has transitioned to a stateless architecture to improve reliability and scaling for AI agent servers.