Custom Agents

Use @embarkai/mcp programmatically in your own AI agent or application.

Using as a library

The package exports createMcpServer and startMcpServer functions that you can use to embed the MCP server in your own process.

Start with stdio transport

The simplest approach — start the server and let it communicate over stdin/stdout:


import { startMcpServer } from '@embarkai/mcp';
 
await startMcpServer({
  apiKey: process.env.EMBARK_API_KEY!,
  walletId: process.env.EMBARK_WALLET_ID!,
  chainId: 2030232745,
  keyshareDir: './data/keyshares',
  keysharePassword: process.env.EMBARK_KEYSHARE_PASSWORD,
  walletBackupPassword: process.env.EMBARK_WALLET_BACKUP_PASSWORD,
  debug: false,
});

You can also call startMcpServer() without arguments to use the default resolveConfig(), which reads from environment variables.

Create server with custom transport

For more control, use createMcpServer to get the McpServer instance and connect your own transport:


import { createMcpServer, resolveConfig } from '@embarkai/mcp';
import { StdioServerTransport } from '@modelcontextprotocol/sdk/server/stdio.js';
 
const config = resolveConfig(); // reads from env vars
const server = await createMcpServer(config);
 
// Connect to stdio (or any other transport)
const transport = new StdioServerTransport();
await server.connect(transport);

Running as a subprocess

The most common pattern for custom agents is to spawn the MCP server as a child process and communicate over stdio using the @modelcontextprotocol/sdk client.

Install dependencies


npm install @modelcontextprotocol/sdk @embarkai/mcp

Client example


import { Client } from '@modelcontextprotocol/sdk/client/index.js';
import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
 
// Spawn the MCP server as a child process
const transport = new StdioClientTransport({
  command: 'npx',
  args: ['-y', '@embarkai/mcp'],
  env: {
    ...process.env,
    EMBARK_API_KEY: 'your_api_key',
    EMBARK_WALLET_ID: 'your_wallet_id',
    EMBARK_CHAIN_ID: '2030232745',
  },
});
 
const client = new Client(
  { name: 'my-agent', version: '1.0.0' },
  { capabilities: {} },
);
 
await client.connect(transport);
 
// List available tools
const { tools } = await client.listTools();
console.log('Available tools:', tools.map(t => t.name));
 
// Call a tool
const result = await client.callTool({
  name: 'get_wallet_info',
  arguments: {},
});
console.log('Wallet info:', result.content);
 
// Check balance
const balance = await client.callTool({
  name: 'get_balance',
  arguments: {},
});
console.log('Balance:', balance.content);
 
// Transfer tokens
const transfer = await client.callTool({
  name: 'transfer',
  arguments: {
    to: '0xRecipientAddress',
    amount: '0.1',
  },
});
console.log('Transfer result:', transfer.content);
 
// Clean up
await client.close();

Integrating with LLM frameworks

With LangChain

If your agent framework supports MCP tools, pass the tool definitions from client.listTools() to your LLM chain. The MCP SDK handles serialization and transport.


import { Client } from '@modelcontextprotocol/sdk/client/index.js';
import { StdioClientTransport } from '@modelcontextprotocol/sdk/client/stdio.js';
 
// Set up the MCP client (as shown above)
const transport = new StdioClientTransport({
  command: 'npx',
  args: ['-y', '@embarkai/mcp'],
  env: {
    ...process.env,
    EMBARK_API_KEY: process.env.EMBARK_API_KEY!,
    EMBARK_WALLET_ID: process.env.EMBARK_WALLET_ID!,
  },
});
 
const client = new Client(
  { name: 'langchain-agent', version: '1.0.0' },
  { capabilities: {} },
);
await client.connect(transport);
 
// Get tool definitions for your LLM
const { tools } = await client.listTools();
 
// Convert MCP tools to your framework's tool format
// and use client.callTool() as the execution handler

Configuration reference

The McpConfig interface accepted by createMcpServer:


interface McpConfig {
  apiKey: string;           // EmbarkAI API key (required)
  walletId: string;         // Wallet identifier (required)
  chainId: number;          // Initial chain ID (default: 2030232745)
  keyshareDir: string;      // Keyshare storage directory
  keysharePassword?: string; // Encryption password for file-based storage
  walletBackupPassword?: string; // Password for vault backup restore
  debug: boolean;           // Enable debug logging
}

See Setup & Installation for details on each configuration option.