How to let AI agents manage your database schema (with MCP)

AI agents are becoming first-class citizens in developer workflows. They can read code, run tests, and deploy apps. But one thing they struggle with is understanding database schemas. Database design tools haven't changed in 20 years. You either use a heavyweight desktop app (Navicat, PDManer) or a pretty but closed web app (dbdiagram). Neither supports versioning, real-time collaboration, or AI agent integration. I built ERD Online to solve this. It's an open-source database design tool that combines Git-like versioning with Figma-like collaboration, plus MCP integration for AI agents. In this article, I'll show you how to let Cursor, Claude, or Cline read and write your database schema through MCP, while you keep full control. Database schema changes are hard to track: Who changed what? When did they change it? Why did they change it? How do I rollback? And now with AI agents, there's a new problem: how do you let an AI agent suggest schema changes without giving it a black box that generates random ER diagrams? The wrong approach: ask AI to "generate an ER diagram for an e-commerce app." You get a diagram, but it has no connection to your actual project, no versioning, and no approval flow. The right approach: let the AI agent read your existing schema, suggest changes, and submit them as a version that you review and approve. That's what ERD Online + MCP does. MCP (Model Context Protocol) is a protocol for AI agents to interact with external tools. Think of it as a USB-C port for AI applications. It standardizes how agents discover and call tools. MCP has three main primitives: Tools : Functions the AI can call (like list_projects or create_version ) Resources : Data the AI can read (like project.json ) Prompts : Pre-defined templates for common tasks ERD Online exposes MCP tools that let AI agents: list_projects : List all your ERD projects get_project : Get a project's projectJSON create_version : Suggest a new version of your schema The key boundary: AI agent