┌─────────────────┐  WebSocket   ┌──────────────────────┐  HTTP/SSE   ┌──────────────┐
│  Tool Provider  │ ───────────→ │  Cloudflare Worker   │ ──────────→ │  MCP Client  │
│  (Extension,    │              │  (Durable Object)    │             │  (VS Code,   │
│   App, Script)  │  register    │                      │ tools/list  │   Claude,    │
│                 │  tools       │  dynamic registry    │ tools/call  │   Cursor)    │
│  execute        │─────────────→│  + bridge            │───────────→│              │
│  tools          │←─────────────│  forward calls       │←───────────│  AI agent    │
│                 │  callTool    │                      │             │  discovers   │
└─────────────────┘              └──────────────────────┘             └──────────────┘

git clone <this-repo>
cd mcp-bridge-cf
npm install
npx wrangler login
npm run deploy

const ws = new WebSocket("wss://mcp-bridge.<subdomain>.workers.dev/ws/extension")

// Register tools
ws.send(JSON.stringify({
  type: "registerTools",
  tools: [
    {
      name: "my_tool",
      description: "Does something useful",
      inputSchema: {
        type: "object",
        properties: {
          query: { type: "string", description: "Input query" }
        },
        required: ["query"]
      }
    }
  ]
}))

// Handle tool calls from MCP client
ws.onmessage = (event) => {
  const msg = JSON.parse(event.data)
  if (msg.type === "callTool") {
    // Execute the tool
    const result = executeMyTool(msg.name, msg.params)

    // Send result back
    ws.send(JSON.stringify({
      type: "toolResult",
      callId: msg.callId,
      result: {
        content: [{ type: "text", text: JSON.stringify(result) }]
      }
    }))
  }
}

{
  "mcp": {
    "servers": {
      "bridge": {
        "url": "https://mcp-bridge.<subdomain>.workers.dev/mcp"
      }
    }
  }
}

{
  "mcpServers": {
    "bridge": {
      "url": "https://mcp-bridge.<subdomain>.workers.dev/mcp"
    }
  }
}

{
  "type": "registerTools",
  "tools": [
    {
      "name": "tool_name",
      "description": "What it does",
      "inputSchema": { "type": "object", "properties": { ... } }
    }
  ]
}

{
  "type": "unregisterTools",
  "names": ["tool_name"]
}

{
  "type": "toolResult",
  "callId": "uuid-from-bridge",
  "result": {
    "content": [{ "type": "text", "text": "result data" }],
    "isError": false
  }
}

{
  "type": "callTool",
  "callId": "unique-id",
  "name": "tool_name",
  "params": { "query": "value" }
}

{ "type": "ping" }

npm run dev      # Local dev with wrangler
npm run typecheck

import OAuthProvider from "@cloudflare/workers-oauth-provider"

export default new OAuthProvider({
  apiRoute: "/mcp",
  apiHandler: createMcpHandler(createServer),
  // ... OAuth config
})