Agentic UI with Markdown as the Protocol

I noticed Gemini in Gmail rendering a small interactive UI directly in chat. That made me wonder whether agents could build new interfaces on the fly.

I explored some ideas and built a small prototype around three principles: code first, Markdown as protocol (text, code, data in one stream), and agent-emitted UIs via a simple mount() primitive.

Thoughts welcome! Especially around security and sandboxing of agent-generated code.