AI Tool Calling & MCP

npm i @anthropic-ai/sdk @nangohq/node

import Anthropic from "@anthropic-ai/sdk";
import { Nango } from "@nangohq/node";

export async function runAnthropicAgent() {
  const client = new Anthropic({ apiKey: process.env.ANTHROPIC_API_KEY! });
  const nango = new Nango({ secretKey: process.env.NANGO_SECRET_KEY! });

  const userId = "user1";
  const integrationId = "hubspot";

  // Step 1: Ensure the user is authorized
  const connections = await nango.listConnections({
    integrationId,
    tags: { end_user_id: userId }
  });
  let connectionId = connections.connections[0]?.connection_id;

  // Step 2: If not authorized, redirect to the auth flow
  if (!connectionId) {
    const session = await nango.createConnectSession({
      allowed_integrations: [integrationId],
      tags: { end_user_id: userId }
    });
    console.log(`Authorize at: ${session.data.connect_link}`);

    const connection = await nango.waitForConnection(integrationId, userId);
    connectionId = connection!.connection_id;
  }

  // Step 3: Send a prompt with tool definitions
  const message = await client.messages.create({
    model: "claude-sonnet-4-5",
    max_tokens: 1024,
    messages: [
      {
        role: "user",
        content: "Using the who_am_i tool, provide the current user info."
      }
    ],
    tools: [
      {
        name: "who_am_i",
        description: "Get the current user info.",
        input_schema: {
          type: "object",
          properties: {},
          required: []
        }
      }
    ],
    tool_choice: { type: "auto" }
  });

  const toolUse = message.content.find((c) => c.type === "tool_use");

  if (toolUse && toolUse.type === "tool_use" && toolUse.name === "who_am_i") {
    // Step 4: Execute the tool via Nango
    const userInfo = await nango.triggerAction(integrationId, connectionId, "whoami");
    console.log("HubSpot user info:", userInfo);
  }
}

npm i ai @nangohq/node

import { generateText, tool } from "ai";
import { openai } from "@ai-sdk/openai";
import { Nango } from "@nangohq/node";
import { z } from "zod";

const nango = new Nango({ secretKey: process.env.NANGO_SECRET_KEY! });

const result = await generateText({
  model: openai("gpt-4o"),
  prompt: "Get the current HubSpot user info.",
  tools: {
    who_am_i: tool({
      description: "Get the current user info from HubSpot.",
      parameters: z.object({}),
      execute: async () => {
        return await nango.triggerAction("hubspot", "conn-user1", "whoami");
      }
    })
  }
});

console.log(result.text);

npm i langchain @langchain/openai @nangohq/node

import { ChatOpenAI } from "@langchain/openai";
import { DynamicTool } from "langchain/tools";
import { AgentExecutor, createOpenAIToolsAgent } from "langchain/agents";
import { ChatPromptTemplate } from "@langchain/core/prompts";
import { Nango } from "@nangohq/node";

const nango = new Nango({ secretKey: process.env.NANGO_SECRET_KEY! });

const whoAmITool = new DynamicTool({
  name: "who_am_i",
  description: "Get the current user info from HubSpot.",
  func: async () => {
    const result = await nango.triggerAction("hubspot", "conn-user1", "whoami");
    return JSON.stringify(result);
  }
});

const model = new ChatOpenAI({ model: "gpt-4o" });
const prompt = ChatPromptTemplate.fromMessages([
  ["system", "You are a helpful assistant."],
  ["human", "{input}"],
  ["placeholder", "{agent_scratchpad}"]
]);

const agent = await createOpenAIToolsAgent({ llm: model, tools: [whoAmITool], prompt });
const executor = new AgentExecutor({ agent, tools: [whoAmITool] });

const result = await executor.invoke({ input: "Who is the current HubSpot user?" });
console.log(result.output);