MCP Ethereum Address Info Server

This server provides information about Ethereum addresses across multiple chains using the Model Context Protocol (MCP). It includes a Server-Sent Events (SSE) endpoint for real-time updates.

Table of Contents

- Setup
- Running the Server
- Available Endpoints
- Using the SSE Endpoint
- Testing with Curl
- Example Workflow

Setup

1. Clone the repository:

   git clone <repository-url>

   cd mcp-0x-address

   

2. Install dependencies:

   npm install

   

3. Create a .env file with the following variables:

   MCP_PORT=3002

   

Running the Server

Start the HTTP MCP server:

npm run start:http

This will start the server on port 3002 (or the port specified in your .env file).

Available Endpoints

The server provides the following endpoints:

- GET /health - Server health check
- POST /mcp - MCP endpoint for tool calls
- GET /sse - Server-Sent Events endpoint for real-time updates
- GET /sse/clients - Get information about connected SSE clients
- POST /sse/subscribe/:clientId - Subscribe to address updates
- POST /sse/unsubscribe/:clientId - Unsubscribe from address updates

Using the SSE Endpoint

The SSE endpoint allows clients to receive real-time updates from the server. Here's how to use it:

1. Connect to the SSE endpoint
2. Get your client ID from the connection response
3. Subscribe to specific addresses
4. Receive real-time updates for those addresses

Testing with Curl

1. Connect to the SSE Endpoint

curl -N http://localhost:3002/sse

This will establish a connection to the SSE endpoint and start receiving events. The connection will remain open until you manually terminate it.

2. Check Connected Clients

curl http://localhost:3002/sse/clients

3. Subscribe to Address Updates

After connecting to the SSE endpoint, you'll receive a client ID. Use that ID to subscribe to address updates:

curl -X POST \
  http://localhost:3002/sse/subscribe/YOUR_CLIENT_ID \
  -H "Content-Type: application/json" \
  -d '{"addresses": ["0x742d35Cc6634C0532925a3b844Bc454e4438f44e", "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2"]}'

Replace YOUR_CLIENT_ID with the client ID you received when connecting to the SSE endpoint.

4. Unsubscribe from Address Updates

curl -X POST \
  http://localhost:3002/sse/unsubscribe/YOUR_CLIENT_ID \
  -H "Content-Type: application/json" \
  -d '{"addresses": ["0x742d35Cc6634C0532925a3b844Bc454e4438f44e"]}'

5. Trigger an Address Update

To trigger an address update (which will be sent to subscribed clients), call the get-address-info tool:

curl -X POST \
  http://localhost:3002/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "get-address-info",
      "arguments": {
        "address": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e"
      }
    }
  }'

6. Check Server Health

curl http://localhost:3002/health

7. Test the Ping Tool

curl -X POST \
  http://localhost:3002/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "ping",
      "arguments": {}
    }
  }'

Example Workflow

Here's a complete workflow for testing the SSE functionality:

1. Start the server:

   npm run start:http

   

2. In a new terminal, connect to the SSE endpoint:

   curl -N http://localhost:3002/sse

   

You'll receive a response like:

   data: {"type":"connection","clientId":"client-1234567890abcdef","message":"Connected to MCP SSE endpoint","timestamp":"2023-01-01T00:00:00.000Z"}

   

3. Note the clientId from the response.

4. In another terminal, subscribe to address updates:

   curl -X POST \

     http://localhost:3002/sse/subscribe/client-1234567890abcdef \

     -H "Content-Type: application/json" \

     -d '{"addresses": ["0x742d35Cc6634C0532925a3b844Bc454e4438f44e"]}'

   

5. Trigger an address update:

   curl -X POST \

     http://localhost:3002/mcp \

     -H "Content-Type: application/json" \

     -d '{

       "jsonrpc": "2.0",

       "id": 1,

       "method": "tools/call",

       "params": {

         "name": "get-address-info",

         "arguments": {

           "address": "0x742d35Cc6634C0532925a3b844Bc454e4438f44e"

         }

       }

     }'

   

6. In the terminal where you're connected to the SSE endpoint, you'll see updates for the address.

Automated Testing Script

For a more automated test, you can use this bash script:

#!/bin/bash
Start SSE connection in the background and capture the output
curl -N http://localhost:3002/sse > sse_output.txt &
SSE_PID=$!
Wait a moment for the connection to establish
sleep 2
Extract the client ID from the output
CLIENT_ID=$(grep -o '"clientId":"[^"]*"' sse_output.txt | head -1 | cut -d'"' -f4)
if [ -z "$CLIENT_ID" ]; then

  echo "Failed to get client ID"

  kill $SSE_PID

  exit 1

fi
echo "Connected with client ID: $CLIENT_ID"
Subscribe to an address
curl -X POST \
  http://localhost:3002/sse/subscribe/$CLIENT_ID \
  -H "Content-Type: application/json" \
  -d '{"addresses": ["0x742d35Cc6634C0532925a3b844Bc454e4438f44e"]}'
echo "Subscribed to address. Waiting for updates..."

echo "Press Ctrl+C to stop"
Keep the script running to see updates
tail -f sse_output.txt
Clean up on exit
trap "kill $SSE_PID; rm sse_output.txt" EXIT

Save this as test_sse.sh, make it executable with chmod +x test_sse.sh, and run it with ./test_sse.sh.