How to integrate Calendarhero MCP with LangChain

This guide walks you through connecting Calendarhero to LangChain using the Composio tool router. By the end, you'll have a working Calendarhero agent that can schedule a meeting with your project team, list all meetings i have this week, fetch details for your next scheduled meeting through natural language commands. This guide will help you understand how to give your LangChain agent real control over a Calendarhero account through Composio's Calendarhero MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Calendarhero is a powerful scheduling platform that streamlines your calendar management across multiple services. It helps you efficiently schedule, reschedule, and organize meetings without the back-and-forth.

38 Tools

Introduction

This guide walks you through connecting Calendarhero to LangChain using the Composio tool router. By the end, you'll have a working Calendarhero agent that can schedule a meeting with your project team, list all meetings i have this week, fetch details for your next scheduled meeting through natural language commands.

This guide will help you understand how to give your LangChain agent real control over a Calendarhero account through Composio's Calendarhero MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

Also integrate Calendarhero with

OpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenClawHermesCLIGoogle ADKVercel AI SDKMastra AILlamaIndexCrewAI

TL;DR

Here's what you'll learn:
  • Get and set up your OpenAI and Composio API keys
  • Connect your Calendarhero project to Composio
  • Create a Tool Router MCP session for Calendarhero
  • Initialize an MCP client and retrieve Calendarhero tools
  • Build a LangChain agent that can interact with Calendarhero
  • Set up an interactive chat interface for testing

What is LangChain?

LangChain is a framework for developing applications powered by language models. It provides tools and abstractions for building agents that can reason, use tools, and maintain conversation context.

Key features include:

  • Agent Framework: Build agents that can use tools and make decisions
  • MCP Integration: Connect to external services through Model Context Protocol adapters
  • Memory Management: Maintain conversation history across interactions
  • Multi-Provider Support: Works with OpenAI, Anthropic, and other LLM providers

What is the Calendarhero MCP server, and what's possible with it?

The Calendarhero MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Calendarhero account. It provides structured and secure access to your calendar management tools, so your agent can schedule meetings, manage contacts, fetch meeting details, and access your calendar integrations on your behalf.

  • Automated meeting scheduling and requests: Easily have your agent schedule new meetings, select participants, set time ranges, and include extra meeting details in just a few steps.
  • Contact creation and management: Let the agent create new contacts or fetch existing ones, so scheduling is always quick and accurate.
  • Meeting details retrieval: Ask your agent to fetch specific meeting details or get a list of all meetings within a defined timeframe, keeping you up-to-date.
  • Access and manage calendar integrations: Direct your agent to list all connected calendars, add new integrations, or access available calendars for streamlined scheduling.
  • Template and meeting type discovery: Quickly retrieve available meeting templates and types, letting your agent optimize scheduling based on your preferences and routines.

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

Composio's Composio SDK helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Composio SDK

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Composio SDK works

The Composio SDK follows a three-phase workflow:

  1. Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
  2. Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
  3. Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Step by step10 STEPS
1

Prerequisites

Before starting this tutorial, make sure you have:
  • Python 3.10 or higher installed on your system
  • A Composio account with an API key
  • An OpenAI API key
  • Basic familiarity with Python and async programming
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
  • Keep the API key safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Navigate to your API settings and generate a new API key.
  • Store this key securely as you'll need it for authentication.
3

Install dependencies

npm install @composio/langchain @langchain/core @langchain/openai @langchain/mcp-adapters dotenv

Install the required packages for LangChain with MCP support.

What's happening:

  • @composio/langchain provides Composio integration for LangChain
  • @langchain/mcp-adapters enables MCP client connections
  • @langchain/core is the core agent framework
  • dotenv/config loads environment variables
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_composio_user_id_here
OPENAI_API_KEY=your_openai_api_key_here

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your requests to Composio's API
  • COMPOSIO_USER_ID identifies the user for session management
  • OPENAI_API_KEY enables access to OpenAI's language models
5

Import dependencies

import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

dotenv.config();
What's happening:
  • We're importing LangChain's MCP adapter and Composio SDK
  • The dotenv/config import loads environment variables from your .env file
  • This setup prepares the foundation for connecting LangChain with Calendarhero functionality through MCP
6

Initialize Composio client

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });
What's happening:
  • We're loading the COMPOSIO_API_KEY from environment variables and validating it exists
  • Creating a Composio instance that will manage our connection to Calendarhero tools
  • Validating that COMPOSIO_USER_ID is also set before proceeding
7

Create a Tool Router session

const session = await composio.create(
    userId as string,
    {
        toolkits: ['calendarhero']
    }
);

const url = session.mcp.url;
What's happening:
  • We're creating a Tool Router session that gives your agent access to Calendarhero tools
  • The create method takes the user ID and specifies which toolkits should be available
  • The returned session.mcp.url is the MCP server URL that your agent will use
  • This approach allows the agent to dynamically load and use Calendarhero tools as needed
8

Configure the agent with the MCP URL

const client = new MultiServerMCPClient({
    "calendarhero-agent": {
        transport: "http",
        url: url,
        headers: {
            "x-api-key": process.env.COMPOSIO_API_KEY
        }
    }
});

const tools = await client.getTools();

const agent = createAgent({ model: "gpt-5", tools });
What's happening:
  • We're creating a MultiServerMCPClient that connects to our Calendarhero MCP server via HTTP
  • The client is configured with a name and the URL from our Tool Router session
  • getTools() retrieves all available Calendarhero tools that the agent can use
  • We're creating a LangChain agent using the GPT-5 model
9

Set up interactive chat interface

let conversationHistory: any[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
console.log("Ask any Calendarhero related question or task to the agent.\n");

const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: 'You: '
});

rl.prompt();

rl.on('line', async (userInput: string) => {
    const trimmedInput = userInput.trim();

    if (['exit', 'quit', 'bye'].includes(trimmedInput.toLowerCase())) {
        console.log("\nGoodbye!");
        rl.close();
        process.exit(0);
    }

    if (!trimmedInput) {
        rl.prompt();
        return;
    }

    conversationHistory.push({ role: "user", content: trimmedInput });
    console.log("\nAgent is thinking...\n");

    const response = await agent.invoke({ messages: conversationHistory });
    conversationHistory = response.messages;

    const finalResponse = response.messages[response.messages.length - 1]?.content;
    console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\n👋 Session ended.');
        process.exit(0);
    });
What's happening:
  • We initialize an empty conversationHistory list to maintain context across interactions
  • A readline interface is used to continuously accept user input from the command line
  • When a user types a message, it's added to the conversation history and sent to the agent
  • The agent processes the request using the invoke() method with the full conversation history
  • Users can type 'exit', 'quit', or 'bye' to end the chat session gracefully
10

Run the application

main().catch((err) => {
    console.error('Fatal error:', err);
    process.exit(1);
});
What's happening:
  • We call the main() function to start the application

Complete Code

Here's the complete code to get you started with Calendarhero and LangChain:

import { Composio } from '@composio/core';
import { LangchainProvider } from '@composio/langchain';
import { MultiServerMCPClient } from "@langchain/mcp-adapters";  
import { createAgent } from "langchain";
import * as readline from 'readline';
import 'dotenv/config';

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.COMPOSIO_USER_ID;

if (!composioApiKey) throw new Error('COMPOSIO_API_KEY is not set');
if (!userId) throw new Error('COMPOSIO_USER_ID is not set');

async function main() {
    const composio = new Composio({
        apiKey: composioApiKey as string,
        provider: new LangchainProvider()
    });

    const session = await composio.create(
        userId as string,
        {
            toolkits: ['calendarhero']
        }
    );

    const url = session.mcp.url;
    
    const client = new MultiServerMCPClient({
        "calendarhero-agent": {
            transport: "http",
            url: url,
            headers: {
                "x-api-key": process.env.COMPOSIO_API_KEY
            }
        }
    });
    
    const tools = await client.getTools();
  
    const agent = createAgent({ model: "gpt-5", tools });
    
    let conversationHistory: any[] = [];
    
    console.log("Chat started! Type 'exit' or 'quit' to end the conversation.\n");
    console.log("Ask any Calendarhero related question or task to the agent.\n");
    
    const rl = readline.createInterface({
        input: process.stdin,
        output: process.stdout,
        prompt: 'You: '
    });

    rl.prompt();

    rl.on('line', async (userInput: string) => {
        const trimmedInput = userInput.trim();
        
        if (['exit', 'quit', 'bye'].includes(trimmedInput.toLowerCase())) {
            console.log("\nGoodbye!");
            rl.close();
            process.exit(0);
        }
        
        if (!trimmedInput) {
            rl.prompt();
            return;
        }
        
        conversationHistory.push({ role: "user", content: trimmedInput });
        console.log("\nAgent is thinking...\n");
        
        const response = await agent.invoke({ messages: conversationHistory });
        conversationHistory = response.messages;
        
        const finalResponse = response.messages[response.messages.length - 1]?.content;
        console.log(`Agent: ${finalResponse}\n`);
        
        rl.prompt();
    });

    rl.on('close', () => {
        console.log('\nSession ended.');
        process.exit(0);
    });
}

main().catch((err) => {
    console.error('Fatal error:', err);
    process.exit(1);
});

Conclusion

You've successfully built a LangChain agent that can interact with Calendarhero through Composio's Tool Router.

Key features of this implementation:

  • Dynamic tool loading through Composio's Tool Router
  • Conversation history maintenance for context-aware responses
  • Async Python provides clean, efficient execution of agent workflows
You can extend this further by adding error handling, implementing specific business logic, or integrating additional Composio toolkits to create multi-app workflows.
TOOLS

Supported Tools

Every Calendarhero action and event your agent gets out of the box.

Add Calendar Connection

Add a new calendar directory/connection to the user's CalendarHero account.

Create Contact

Creates a new contact in CalendarHero with the provided contact information.

Create Meeting Request V2

Tool to create a new meeting request in CalendarHero.

Create Webhook

Creates or updates a webhook for a specific event type in CalendarHero.

Delete Contact

Tool to delete a contact from CalendarHero by its unique identifier.

Delete Meeting Task

Tool to delete a meeting task/request from CalendarHero.

Delete Meeting Type

Tool to delete a meeting type from the authenticated user's CalendarHero account.

Delete User Directory

Tool to delete a user directory by its UUID.

Delete Webhook

Tool to delete a webhook subscription for a specific event type.

Fetch Contact

Fetch Contact

Fetch Meeting Details

Tool to fetch details for meetings within a specified timeframe.

Fetch User Profile

Tool to fetch the profile details of the authenticated user.

Get Assistant Message

Tool to retrieve a reply message from the CalendarHero assistant.

Get Contact Count

Tool to get the total count of contacts in CalendarHero.

Get Meeting Categories

Retrieves the user's meeting categories' stats for a specified time period.

Get Meeting Tasks

Retrieves the user's meeting requests/tasks from CalendarHero.

Get Search Result

Tool to get a search result by ID.

Get User Directory

Tool to retrieve a user's directory by its unique identifier.

Get User Organization

Tool to retrieve the authenticated user's organization details.

Get User Savings

Tool to retrieve the authenticated user's savings information from CalendarHero.

Get Webhook Configuration

Tool to get webhook configuration for a specific event type.

Get Webhook Sample

Tool to retrieve a sample webhook payload for a specific event type.

List Meeting Templates

Retrieves all meeting templates (reusable meeting configurations) for the authenticated user.

List Meeting Types

Retrieves all meeting types configured for the authenticated CalendarHero user.

List User Calendars

Tool to list all calendar integrations connected to a user's CalendarHero account.

List User Directories

Tool to retrieve all directories configured for a user.

Search Contact

Tool to search for existing contacts.

Search Integrations

Tool to search across all user integrations for a query term.

Send Assistant Message

Tool to send a user's message into the CalendarHero assistant.

Send Reminder

Sends an email reminder to all contacts/participants about a scheduled meeting request.

Update Contact

Updates an existing contact in CalendarHero with new information.

Update Meeting Types

Tool to update meeting type configurations for the authenticated CalendarHero user.

Update Restricted Apps

Tool to update the authenticated user's restricted apps settings.

Update User

Tool to update the authenticated user's profile information.

Update User Address

Tool to update the authenticated user's address settings by providing latitude and longitude coordinates.

Update User Directory

Tool to update a user's directory in CalendarHero.

Update User Info

Updates the authenticated user's info settings in CalendarHero.

Update Work Location

Tool to update the user's work location settings in CalendarHero.

FRAMEWORKS

How to build Calendarhero MCP Agent with another framework

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Calendarhero MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Calendarhero MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Calendarhero MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Calendarhero MCP with Claude Cowork

Codex logo

Codex

Use Calendarhero MCP with Codex

OpenClaw logo

OpenClaw

Use Calendarhero MCP with OpenClaw

Hermes logo

Hermes

Use Calendarhero MCP with Hermes

CLI logo

CLI

Use Calendarhero MCP with CLI

Google ADK logo

Google ADK

Use Calendarhero MCP with Google ADK

Vercel AI SDK logo

Vercel AI SDK

Use Calendarhero MCP with Vercel AI SDK

Mastra AI logo

Mastra AI

Use Calendarhero MCP with Mastra AI

LlamaIndex logo

LlamaIndex

Use Calendarhero MCP with LlamaIndex

CrewAI logo

CrewAI

Use Calendarhero MCP with CrewAI

FAQ

Frequently asked questions

With a standalone Calendarhero MCP server, the agents and LLMs can only access a fixed set of Calendarhero tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Calendarhero and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. LangChain fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Calendarhero tools.

Yes, absolutely. You can configure which Calendarhero scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Calendarhero data and credentials are handled as safely as possible.

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A lot of students tell us that the moment their connected tools start talking to each other inside Opennote feels almost magical. The agent just knows them, and it's immensely helped keep new users on the platform.

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As a solo builder, shipping fast is life or death. The only way I can outcompete incumbents is by outmanoeuvring them. Getting bogged down managing agent auth would have been a death sentence.

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Before Composio, adding tool integrations was slow and resource-intensive. Each one could take weeks of engineering time, and maintaining them meant constantly keeping up with API changes.

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