web2mcp

A system that automatically generates expressive Model Context Protocol (MCP) implementations for any web application (SaaS or consumer-facing).

Problem Statement

Design a system that, given any web application (SaaS or consumer-facing), can automatically generate an expressive Model Control Protocol (MCP) implementation.

This is a fairly hard problem for (at least) three reasons:

• Behavior tree size: Apps have many buttons and pages. We must traverse at least the important subset of these buttons and pages to establish an application's capabilities.

• Semantic gap: While links/buttons can be easily identified, it's not clear when these links/buttons correspond to a meaningful tool to expose via the MCP. Similarly, what textual information on the page is relevant for read operations?

• Under-specified hierarchy: We must infer the object hierarchy. What are the "resources" that the MCP should allow agents to act on? Which tools correspond to which resources?

I break the problem into two separate tasks: (1) define the MCP specification and (2) implement the specification.

Installation

Prerequisites

1. Python Dependencies (for the test application):

   cd test
   pip3 install -r requirements.txt

2. Node.js Setup:

   nvm use 18
   npm install

3. Environment Variables:

   cp .env.example .env

   Then edit .env and set the following variables:

   BROWSERBASE_PROJECT_ID="YOUR_BROWSERBASE_PROJECT_ID"
   BROWSERBASE_API_KEY="YOUR_BROWSERBASE_API_KEY"
   OPENAI_API_KEY="THIS_IS_OPTIONAL_WITH_OPENAI_KEY"
   # SPA Crawler Configuration
   SPA_CRAWLER_URL="http://localhost:8000"
   SPA_CRAWLER_USERNAME="[email protected]"
   SPA_CRAWLER_PASSWORD="password123"
   SPA_CRAWLER_MAX_DEPTH="1"
   SPA_CRAWLER_ENV="LOCAL"

   By default, the SPA_* environment variables work for the demo app.

Getting Started

Example MCP Implementation

You can try a derived MCP for the demo email application:

1. Run the demo app:

   cd test
   python3 app.py

2. In a new terminal in the root directory:

   npm run build:mcp
   npx @modelcontextprotocol/inspector node dist/dynamicMcpServer.js test/exampleMcpConfig.json test/exampleSummaryPageActions.json

3. Try the MCP in the launched browser window

Example MCP Derivation

1. Start the demo app:

   cd test
   python3 app.py

2. In the root directory, run the crawler:

   npx tsx spaCrawler.ts

3. The resulting output is in outputMcpConfig.json and outputSummaryPageActions.json

4. Use those with the MCP server:

   npm run build:mcp
   node dist/dynamicMcpServer.js outputMcpConfig.json outputSummaryPageActions.json

Project Structure

• spaCrawler.ts - Main crawler that analyzes web applications and generates MCP configurations
• dynamicMcpServer.ts - Dynamic MCP server implementation
• sharedUtils.ts - Shared utilities for the project
• test/ - Demo Flask application for testing
  • app.py - Simple email application demo
  • exampleMcpConfig.json - Example MCP configuration
  • exampleSummaryPageActions.json - Example page action definitions

How It Works

The system works in two phases:

1. Analysis Phase: The spaCrawler.ts analyzes a web application by:

   • Crawling through pages and identifying interactive elements
   • Inferring the application's object hierarchy
   • Determining which actions correspond to meaningful MCP tools
   • Generating configuration files that define the MCP interface

2. Execution Phase: The dynamicMcpServer.ts provides:

   • A dynamic MCP server that loads configurations at runtime
   • Tool execution that translates MCP calls into web application actions
   • Real-time interaction with the target web application

Development

Building

npm run build:mcp

Running in Development

npx tsx spaCrawler.ts
npx tsx dynamicMcpServer.ts

Testing with MCP Inspector

npx @modelcontextprotocol/inspector node dist/dynamicMcpServer.js config.json actions.json

License

See LICENSE.txt for details.