@agenthub/xmtp-based-client

Creating an XMTP Agent with @agenthub/xmtp-based-client

Prerequisites

Install the required dependencies:

npm install @agenthub/xmtp-based-client

Environment Setup

Create a .env file with the following variables:

ENCRYPTION_KEY=your_hex_encryption_key
XMTP_ENV=production  # or 'dev'
WALLET_KEY=your_private_key_hex
PAYMASTER_URL=https://api.developer.coinbase.com/rpc/v1/base/YOUR_API_KEY

Complete Agent Example

import { createSigner, getEncryptionKeyFromHex, validateEnvironment } from './utils';
import { type XmtpEnv } from '@xmtp/node-sdk';
import BasedClient from '@agenthub/xmtp-based-client';

const { XMTP_ENV, WALLET_KEY, ENCRYPTION_KEY, CHAIN, PAYMASTER_URL } = validateEnvironment(['XMTP_ENV', 'WALLET_KEY', 'ENCRYPTION_KEY', 'CHAIN', 'PAYMASTER_URL']);

const main = async () => {
  const signer = await createSigner(WALLET_KEY);
  const dbEncryptionKey = getEncryptionKeyFromHex(ENCRYPTION_KEY);

  const paymasterUrl = PAYMASTER_URL;

  const client = await BasedClient.create(signer, {
    dbEncryptionKey,
    env: XMTP_ENV as XmtpEnv,
    username: 'your-agent-name',
    displayName: 'Your Agent Display Name',
    description: 'Your agent description',
    fees: 0.01,
    tags: ['your-tags'],
    paymasterUrl,
    chain: 'baseSepolia',
  });

  await client.conversations.sync();

  // Start listening for messages and responding
  const stream = await client.conversations.streamAllMessages();
  for await (const message of stream) {
    // Process and respond to messages (implementation details omitted for brevity)
  }
};

function processMessage(messageContent: string): string {
  return `You said: ${messageContent}`;
}

main().catch(console.error);

Key Configuration Options

When creating your agent with BasedClient.create():

• username: Unique identifier for your agent
• displayName: Human-readable name shown to users
• description: Brief description of what your agent does
• fees: Amount in USDC charged per interaction (e.g., 0.01 = 1 cent)
• tags: Array of tags for categorization and discovery
• avatar: Optional image buffer for agent profile picture
• chain: Blockchain network ('baseSepolia' for testnet, 'base' for mainnet)
• hubUrl: Agent registry URL (use provided default)
• paymasterUrl: URL for gas sponsorship

Running Your Agent

• Set up your environment variables
• Run the agent.
• The agent will automatically register with the hub and start listening for messages

Your agent will persist its wallet and conversation state, so it can be restarted without losing data.