Building Interactive UIs in VS Code with MCP Apps — Marlene Mhangami & Liam Hampton, GitHub

TL;DR

• 1

  MCP apps fix the "text-only" problem: Marlene contrasts early MCP outputs like ASCII art and emoji-heavy readmes with newer apps that return rich, interactive components directly inside chat.

• 2

  VS Code is the host, Copilot is the client, and the server provides the capability: The talk clearly separates MCP's core pieces and recommends finding servers through VS Code's @mcp extension list or GitHub rather than installing random ones from the internet.

• 3

  The UI flow is server to resource reference to sandboxed iframe: An MCP server returns tool results plus a reference to HTML, then VS Code fetches and renders that UI in an iframe where users can interact safely.

• 4

  Interactive chat matters most when clicking beats prompting: Marlene uses data exploration and in-chat commerce as examples where users should inspect charts or complete checkout flows without constantly typing follow-up instructions.

• 5

  Companies like Shopify, Excalidraw, and Figma are already building this way: Shopify is focused on preserving brand identity inside chat, while Excalidraw and Figma use MCP apps for editable diagrams and generated components.

• 6

  Liam's flame graph demo shows the practical value: He profiles a Go app over 5 seconds via a local MCP server and renders the results as an interactive React UI in Copilot, replacing back-and-forth questions like "is this good or bad?" with a visual answer.