If you’ve been diving into the world of AI-assisted programming or tool-calling protocols, you might have come across Model Context Protocol (MCP). MCP is an open-source standard for connecting AI applications to external systems. It is a lightweight framework that lets you expose functions as “tools” to language models, enabling seamless interaction between AI agents and your code. Think of it as a bridge that turns your functions into callable endpoints for models.

In this post, we’ll build a basic in-memory database server using MCP, with code samples to extend and learn from. We’ll dissect the code step by step, and by the end, you’ll have a working prototype. Plus, I’ll ask you to extend it with update, delete, and drop functionalities. Let’s turn your terminal into a mini SQL playground!