A lightweight chat UI for talking to OpenAI models that can use MCP servers as tools. Built on Val Town with Hono.

Point it at any MCP server URL, ask a question, and the model will discover and call tools on its own.

Rendering mermaid diagram...

• Plug in any MCP server — add/remove server URLs in the sidebar. Ships with a dice roller as a default.
• Multiple threads — conversations persist in localStorage.
• Tool call inspector — click any tool call to expand arguments and output.
• Model picker — switch between gpt-4.1, gpt-4.1-mini, gpt-4.1-nano, gpt-4o, o3, o4-mini.

1. Fork this val
2. Set the OPENAI_API_KEY environment variable in your val's settings
3. That's it — open the endpoint URL

index.tsx          → Hono HTTP entrypoint, serves HTML + routes
api/
  chat.ts          → POST /api/chat — proxies to OpenAI with MCP tools
ui/
  Layout.tsx       → HTML shell
  Sidebar.tsx      → Thread list, MCP server manager, settings
  ChatArea.tsx     → Message area + input bar
  client.ts        → All client-side JS (threads, MCP, send loop)
  styles.ts        → CSS