OpenGenUI MCP

An MCP Apps-capable MCP server that turns a natural-language description into an interactive HTML/JS UI component, rendered in any compliant MCP host (Microsoft 365 Copilot declarative agents, Claude Desktop, VS Code, Copilot Cowork).

The server exposes a single tool — generate_ui_component(description) — that drives the OpenGenerativeUI LangGraph deep agent over the AG-UI protocol, captures the agent’s widgetRenderer tool call, and serves the result as a sandboxed MCP App view.

[!WARNING] This is a tech demo, not an enterprise-ready product. It deliberately ships with:

• Maximally permissive CSP in the rendered iframe ('unsafe-inline', 'unsafe-eval', several CDN domains) so the agent’s arbitrary HTML/JS executes without friction.
• No authentication on the HTTP transport — open to anything that can reach localhost:3101.
• No rate limiting, no input validation, no audit trail beyond per-call debug logs.
• Execution of unaudited LLM-generated JavaScript in the user’s host (sandboxed in an iframe, but still arbitrary code).

Do not deploy this as-is anywhere reachable from a network you don’t control. Hardening for production would need (at minimum) authentication, a narrow CSP scoped to specific CDNs with 'unsafe-eval' dropped, supply-chain review, and a careful look at how agent output flows into the host.

See spec.md for the full design, decisions log, and architecture diagram.

Prerequisites

• Node.js 20+

• The OpenGenerativeUI agent running at http://localhost:8123/. From a clone of CopilotKit/OpenGenerativeUI:

  make dev-agent
  

  The agent requires an OPENAI_API_KEY (or equivalent for whichever provider you configure) in apps/agent/.env. Strong models only — weak models produce broken visualizations (the agent’s own README spells out which models are supported).

Install, build, run

npm install
npm run build      # bundles the View into dist/mcp-app.html (single file)
npm run serve      # HTTP transport on http://localhost:3101/mcp
# or
npm run serve:stdio   # stdio transport for Claude Desktop

npm run dev runs Vite in watch mode plus tsx watching the server.

Configuration