LangChain Implementation Example

This guide shows how to integrate Boson Protocol commerce capabilities into a LangChain AI agent. The bosonprotocol/agent-builder repository contains different AI agent examples using Boson tools, with the LangChain example at src/examples/standalone/langchain/index.ts.

Integration Code Snippets

1. Getting Boson Tools

import { bosonProtocolPlugin } from "@bosonprotocol/agentic-commerce";
import { BOSON_MCP_URL, CHAIN_MAP } from "@common/chains.ts";
import { getOnChainTools } from "@goat-sdk/adapter-langchain";
import { viem } from "@goat-sdk/wallet-viem";

// Get tools with the Boson Protocol plugin
const tools = await getOnChainTools({
  wallet: viem(walletClient),
  plugins: [bosonProtocolPlugin({ url: bosonMcpUrl })],
});

console.log(
  "Available tools:",
  tools.map((tool: any) => tool.name),
);

2. LangChain Agent Integration

import { ChatAnthropic } from "@langchain/anthropic";
import { AgentExecutor, createStructuredChatAgent } from "langchain/agents";
import { pull } from "langchain/hub";

// Initialize LLM
const llm = new ChatAnthropic({
  apiKey: anthropicApiKey,
  model: "claude-4-sonnet-20250514", // change model as needed,
  temperature: 0,
});

// Pull the structured chat agent system prompt from LangChain Hub
const systemPrompt = await pull<ChatPromptTemplate>(
  "hwchase17/structured-chat-agent",
);

// Create structured chat agent
const agent = await createStructuredChatAgent({
  llm,
  tools: tools as any, // Type assertion to resolve complex type inference
  prompt: systemPrompt,
});

const agentExecutor = new AgentExecutor({
  agent,
  tools: tools as any,
});

Transaction Signing

The example shows how wallet setup enables automatic transaction signing through the GOAT SDK plugin:

import { createPublicClient, createWalletClient, http } from "viem";
import { privateKeyToAccount } from "viem/accounts";

// Validate and format private key
const privateKey = rawPrivateKey.startsWith("0x")
  ? rawPrivateKey
  : `0x${rawPrivateKey}`;

if (privateKey.length !== 66) {
  throw new Error(
    `Invalid private key length: expected 66 characters (0x + 64 hex), got ${privateKey.length}`,
  );
}

if (!/^0x[0-9a-fA-F]{64}$/.test(privateKey)) {
  throw new Error("Invalid private key format: must be hex string");
}

const account = privateKeyToAccount(privateKey as `0x${string}`);

const walletClient = createWalletClient({
  account,
  chain,
  transport: http(rpcUrl),
});

// Check wallet balance before proceeding
const publicClient = createPublicClient({
  chain,
  transport: http(rpcUrl),
});

const balance = await publicClient.getBalance({ address: account.address });

if (balance === 0n) {
  console.error("❌ Wallet has no balance!");
  console.log("💳 Your address:", account.address);
  process.exit(1);
}

When you provide this wallet client to the GOAT SDK plugin, it handles all transaction signing automatically when the agent calls Boson tools.

Required Environment Variables

BOSON_MCP_URL=https://boson-mcp-server-staging-170470978472.europe-west2.run.app/mcp
CHAIN_ID=80002
PRIVATE_KEY=0x1234567890abcdef1234567890abcdef1234567890abcdef1234567890abcdef
ANTHROPIC_API_KEY=sk-ant-api03-...

Agent Usage Example

const result = await agentExecutor.invoke({
  input: prompt,
  chat_history: chatHistory,
});

console.log(result.output);

// Add messages to chat history for context in next interaction
chatHistory.push(new HumanMessage(prompt));
chatHistory.push(new AIMessage(result.output));

Key Dependencies

{
  "dependencies": {
    "@bosonprotocol/agentic-commerce": "^1.0.0-alpha.90",
    "@goat-sdk/adapter-langchain": "^0.2.12",
    "@goat-sdk/wallet-viem": "^0.3.0",
    "@langchain/anthropic": "^0.3.26",
    "@langchain/core": "^0.3.72",
    "langchain": "^0.3.6"
  }
}

Additional Examples

Other framework implementations in the repository:

• Vercel AI SDK

• Telegram Bot

• Email Integration

Next Steps

1. Clone the Repository: Get the complete working example

2. Set Environment Variables: Configure for your target network

3. Optional - Local Development Setup: For local testing, fork the agentic-commerce repository and follow these steps:

   Step 1: Install and Build

   npm ci
   npm run build

   Step 2: Start E2E Services

   npm run e2e:boson:services
   # Keep this terminal running

   Step 3: Start MCP Server (New Terminal)

   npm run dev:boson:http
   # Keep this terminal running

   Step 4: Optional - Start Inspector (New Terminal)

   npm run dev:boson:http:inspector

   Prerequisites:

   • Make sure you have .env file configured

   • Ensure mcpServer.json exists in project root

4. Run the Example: Test the integration with your setup