Part 1: Why We Built an MCP Server — And What We Learned Before Writing a Single Line of Code

A three-part series on building our first Model Context Protocol server for healthcare interoperability. The Problem That Wouldn't Go Away If you've ever worked in healthcare tech, you know the feeling: someone asks an AI assistant — Claude, ChatGPT, Copilot, whatever — a question about FHIR (Fast Healthcare Interoperability Resources), and the answer is close but dangerously wrong. Maybe it hallucinates a field that doesn't exist in R4. Maybe it confuses a US Core profile with a base resource. Maybe it confidently describes an element that was removed two versions ago. This isn't the AI's fault. FHIR is a vast, versioned specification. The core spec alone has hundreds of StructureDefinitions, ValueSets, and CodeSystems. Layer on Implementation Guides (IGs) like US Core, and you're dealing with thousands of artifacts across multiple versions (R4, R4B, R5). No language model has all of that committed to memory with version-level precision. We kept running into this problem on our team.