A few weeks back, my team sat down for two days and built around twenty MCP Apps. I came out with a much better idea of what they are, what they aren't (yet), and where the duct tape is currently holding things together. Here's the brain dump.
If you haven't run into them yet: MCP Apps is the first official extension to the MCP spec. It lets a tool return a UI resource alongside its result. The host renders that UI inline as a sandboxed iframe. Tables, charts, forms, branded layouts, little interactive bits that can call back into other tools. Real, actual UI in the middle of a chat-based experience. Very cool.
They matter because some information is just better visually. A neatly grouped list of pull requests is much easier to scan than a wall of bulleted text. A chart beats a CSV. And as more of our day-to-day work shifts into chat, "bring your brand and your product surface into the conversation" stops being a nice-to-have.
OK. Lessons.
The call is coming from inside the house
