MCP Apps: Primitives, discovery, and the Future of Software - Pietro Zullo, Manufact, Inc

MCP Apps represent the next evolution of the Model Context Protocol, shifting from simple JSON-based tool calls to interactive, UI-rich experiences embedded directly within LLM chat interfaces. By leveraging sandboxed iframes, these applications enable bidirectional communication between the user and the host, allowing for dynamic state updates and real-time UI rendering as tokens stream. The opening of official stores for platforms like ChatGPT, Claude, and Cursor provides a critical distribution channel, enabling developers to reach millions of users through one-click installations. As AI agents increasingly function as primary interfaces for digital tasks, MCP Apps serve as the modern equivalent of websites, offering a seamless way to integrate external tools and private data into the chat workflow without compromising security or user experience.