Excalidraw-MCP is an open-source Model Context Protocol (MCP) application and server that connects the visual power of Excalidraw’s hand-drawn diagram editor with AI-driven workflows, enabling agents like Claude, ChatGPT, VS Code, and other MCP-compatible hosts to generate and manipulate diagrams programmatically. Rather than being just a static whiteboard, Excalidraw-MCP serves diagrams in real time using an MCP backend and streams interactive visual output back to the client, letting AI tools create shapes, connectors, text, and entire diagrams as part of conversational or task-based sessions. Its design supports fast, streamable rendering with smooth viewport control and optional fullscreen editing so that diagrams feel live and fluid as they evolve. Users can deploy it locally or via services like Vercel, then configure their MCP host to point at the Excalidraw-MCP endpoint, so prompts like “draw an architecture diagram” yield immediate visual results within chat.