mcp2web — Building Web UI MCP Servers

Protocol Overview

mcp2web is a protocol standard for MCP servers that serve HTML/CSS web UIs. An Electron mini-browser connects to these servers and renders their HTML content.

URI Schemes

• Resources: mcp2web://<server-name>/<path> — HTML pages served as MCP resources with mimeType: "text/html"
• Tool Actions: mcp2web-tool://<tool-name> — used as <form action> attributes to trigger MCP tool calls

How It Works

1. MCP server registers resources (HTML pages) and tools (form handlers)
2. Electron browser connects via stdio, lists resources, renders them in a sandboxed iframe
3. Links (<a href="mcp2web://...">) trigger resource reads
4. Forms (<form action="mcp2web-tool://...">) trigger tool calls
5. Tool responses containing HTML are rendered as new pages

Project Scaffolding