LangChain Integration

Setup

npm install @bithaven/mcp-sdk langchain @langchain/openai

Create LangChain Tools

Wrap the BithavenClient methods as DynamicTool instances:

import { BithavenClient, PolicyDeniedError } from '@bithaven/mcp-sdk';
import { DynamicTool } from 'langchain/tools';
import { initializeAgentExecutorWithOptions } from 'langchain/agents';
import { ChatOpenAI } from '@langchain/openai';

const bithaven = new BithavenClient({
  apiKey: process.env.BITHAVEN_API_KEY!,
});

const tools = [
  new DynamicTool({
    name: 'bithaven_check_balance',
    description: 'Check USDC balance and remaining spend caps.',
    func: async () => JSON.stringify(await bithaven.checkBalance()),
  }),

  new DynamicTool({
    name: 'bithaven_send_payment',
    description:
      'Send USDC. Input: JSON { toAddress, amount, memo? }',
    func: async (input: string) => {
      try {
        const params = JSON.parse(input);
        return JSON.stringify(await bithaven.sendPayment(params));
      } catch (err) {
        if (err instanceof PolicyDeniedError) {
          return JSON.stringify({
            error: 'Denied by policy',
            violations: err.violations,
          });
        }
        return JSON.stringify({ error: String(err) });
      }
    },
  }),

  new DynamicTool({
    name: 'bithaven_get_tx_history',
    description: 'Get transaction history. Input: JSON { page?, limit? }',
    func: async (input: string) => {
      const params = input ? JSON.parse(input) : {};
      return JSON.stringify(await bithaven.getTxHistory(params));
    },
  }),

  new DynamicTool({
    name: 'bithaven_request_approval',
    description:
      'Request human approval. Input: JSON { toAddress, amount, memo?, reason? }',
    func: async (input: string) => {
      const params = JSON.parse(input);
      return JSON.stringify(await bithaven.requestApproval(params));
    },
  }),
];

// Create and run the agent
const model = new ChatOpenAI({ modelName: 'gpt-4o', temperature: 0 });
const executor = await initializeAgentExecutorWithOptions(tools, model, {
  agentType: 'openai-functions',
  verbose: true,
});

const result = await executor.invoke({
  input: 'Check my balance, then send 5 USDC to 0x742d...2bD68',
});
console.log(result.output);