From OpenAPI spec to MCP: How we built Xata's MCP server

Model Context Protocol (MCP) is an emerging standard that lets AI models securely interact with tools and APIs in real time. Building an MCP server means exposing a set of “tools” (operations) that a Large Language Model (LLM) can call to perform tasks, for example, fetching data or triggering actions via your backend. Rather than hand-coding each tool, we set out to generate an MCP server from our existing OpenAPI specification, leveraging our API’s schema as a single source of truth. This OpenAPI-driven approach promises quick development and consistency, but it comes with design considerations. On one hand, auto-generating tools directly from a REST API spec is very appealing. You’ve already documented your API thoroughly, so why not transform those endpoints into AI-accessible functions? It saves time and keeps the API and MCP definitions in sync, avoiding duplicate work. On the other hand, a naïve one-to-one mapping of every endpoint to an MCP tool can overwhelm an LLM. LLMs stru ... Read full article.