How to integrate Calendly MCP with LangChain

Q: What are the differences in Tool Router MCP and Calendly MCP?

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

Q: Can I use Tool Router MCP with LangChain?

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 Calendly tools.

Q: Can I manage the permissions and scopes for Calendly while using Tool Router?

Yes, absolutely. You can configure which Calendly 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.

Q: How safe is my data with Composio Tool Router?

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 Calendly data and credentials are handled as safely as possible.

This guide walks you through connecting Calendly to LangChain using the Composio tool router. By the end, you'll have a working Calendly agent that can create a single-use scheduling link for your next meeting, cancel your 2pm event with a reason, mark an invitee as no-show for today's appointment through natural language commands. This guide will help you understand how to give your LangChain agent real control over a Calendly account through Composio's Calendly MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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Calendly

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Calendly is an appointment scheduling tool that automates meeting invitations, availability checks, and reminders. It helps individuals and teams avoid endless email back-and-forth when booking meetings.

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Introduction

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

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

Also integrate Calendly with

ChatGPT OpenAI Agents SDK Claude Agent SDK Claude Code Claude Cowork Codex OpenCode Cursor VS Code OpenClaw Hermes CLI Google ADK Vercel AI SDK Mastra AI LlamaIndex CrewAI

TL;DR

Here's what you'll learn:

Get and set up your OpenAI and Composio API keys
Connect your Calendly project to Composio
Create a Tool Router MCP session for Calendly
Initialize an MCP client and retrieve Calendly tools
Build a LangChain agent that can interact with Calendly
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 Calendly MCP server, and what's possible with it?

The Calendly MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Calendly account. It provides structured and secure access to your scheduling workflows, so your agent can perform actions like creating personalized scheduling links, managing events, handling invitee statuses, and automating reminders on your behalf.

Instant scheduling link creation: Direct your agent to generate single-use or shareable scheduling links so others can book time with you instantly—no more back-and-forth emails.
Automated event and invitee management: Have your agent cancel events, mark invitees as no-shows, or remove no-show statuses to keep your calendar accurate and up to date.
Custom one-off event setup: Empower your agent to create unique, one-off meeting types for special situations, bypassing your regular availability rules.
Webhook subscription automation: Let the agent set up webhook subscriptions to trigger notifications or workflows in real time when events happen in your Calendly account.
Data privacy and compliance actions: Instruct your agent to delete invitee data or scheduled event records as needed for privacy or regulatory compliance, especially for enterprise use cases.

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:

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

Step-by-step Guide

Step by step10 STEPS

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

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.

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

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

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 Calendly functionality through MCP

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 Calendly tools
Validating that COMPOSIO_USER_ID is also set before proceeding

Create a Tool Router session

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

const url = session.mcp.url;

What's happening:

We're creating a Tool Router session that gives your agent access to Calendly 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 Calendly tools as needed

Configure the agent with the MCP URL

const client = new MultiServerMCPClient({
    "calendly-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 Calendly MCP server via HTTP
The client is configured with a name and the URL from our Tool Router session
getTools() retrieves all available Calendly tools that the agent can use
We're creating a LangChain agent using the GPT-5 model

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 Calendly 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

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 Calendly 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: ['calendly']
        }
    );

    const url = session.mcp.url;
    
    const client = new MultiServerMCPClient({
        "calendly-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 Calendly 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 Calendly 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 Calendly action and event your agent gets out of the box.

Cancel scheduled event

Tool to cancel a scheduled Calendly event by creating a cancellation record.

Create Event Type

Tool to create a new one-on-one event type (kind: solo) in Calendly.

Create One-Off Event Type

Creates a temporary Calendly one-off event type for unique meetings outside regular availability, requiring valid host/co-host URIs, a future date/range for `date_setting`, and a positive `duration`.

Create scheduling link

Create a single-use scheduling link.

Create share

Creates a customizable, one-time share link for a Calendly event type, allowing specific overrides to its settings (e.

Create single use scheduling link

Creates a one-time, single-use scheduling link for an active Calendly event type, expiring after one booking.

Create webhook subscription

Tool to create a webhook subscription for receiving Calendly event notifications.

Delete invitee data

Permanently removes all invitee data associated with the provided emails from past organization events, for data privacy compliance (requires Enterprise subscription; deletion may take up to one week).

Delete invitee no show

Deletes an Invitee No-Show record by its `uuid` to reverse an invitee's 'no-show' status; the `uuid` must refer to an existing record.

Delete organization membership

Tool to remove a user from a Calendly organization by membership UUID.

Delete scheduled event data

For Enterprise users, initiates deletion of an organization's scheduled event data between a `start_time` and `end_time` (inclusive, where `start_time` must be <= `end_time`); actual data deletion may take up to 7 days to complete.

Delete webhook subscription

Deletes an existing webhook subscription to stop Calendly sending event notifications to its registered callback URL; this operation is idempotent.

Get event

Use to retrieve a specific Calendly scheduled event by its UUID, provided the event exists in the user's Calendly account.

Get event invitee

Retrieves detailed information about a specific invitee of a scheduled event, using their unique UUIDs.

Get event type

Retrieves details for a specific Calendly event type, identified by its UUID, which must be valid and correspond to an existing event type.

Get event type availability

Tool to retrieve availability schedules configured for a specific Calendly event type.

Get group

Retrieves all attributes of a specific Calendly group by its UUID; the group must exist.

Get group relationship

Retrieves a specific Calendly group relationship by its valid and existing UUID, providing details on user-group associations and membership.

Get invitee no show

Retrieves details for a specific Invitee No Show record by its UUID; an Invitee No Show is marked when an invitee does not attend a scheduled event.

Get organization

Tool to retrieve information about a specific Calendly organization.

Get organization invitation

Retrieves a specific Calendly organization invitation using its UUID and the parent organization's UUID.

Get organization membership

Retrieves a specific Calendly organization membership by its UUID, returning all its attributes.

Get routing form

Retrieves a specific routing form by its UUID, providing its configuration details including questions and routing logic.

Get routing form submission

Tool to retrieve details about a specific routing form submission by its UUID.

Get sample webhook data

Tool to retrieve sample webhook payload data for testing webhook subscriptions.

Get user

Retrieves comprehensive details for an existing Calendly user.

Get user availability schedule

Retrieves an existing user availability schedule by its UUID; this schedule defines the user's default hours of availability.

Get webhook subscription

Retrieves the details of an existing webhook subscription, identified by its UUID, including its callback URL, subscribed events, scope, and state.

Mark invitee as no-show

Tool to mark an invitee as a no-show for a scheduled event.

List activity log entries

Retrieves a list of activity log entries for a specified Calendly organization (requires an active Enterprise subscription), supporting filtering, sorting, and pagination.

List event invitees

Retrieves a list of invitees for a specified Calendly event UUID, with options to filter by status or email, and sort by creation time.

List event type available times

Fetches available time slots for a Calendly event type within a specified time range; results are not paginated.

List event type hosts

Tool to retrieve a list of event type hosts (memberships) for a specific event type.

List Event Types

Tool to list all Event Types associated with a specified User or Organization.

List group relationships

Retrieves a list of group relationships defining an owner's role (e.

List groups

Returns a list of groups for a specified Calendly organization URI, supporting pagination.

List organization invitations

Retrieves a list of invitations for a specific organization, identified by its UUID.

List organization memberships

Retrieves a list of organization memberships.

List outgoing communications

Retrieves a list of outgoing SMS communications for a specified organization; requires an Enterprise subscription and if filtering by creation date, both `min_created_at` and `max_created_at` must be provided to form a valid range.

List routing forms

Retrieves routing forms for a specified organization; routing forms are questionnaires used to direct invitees to appropriate booking pages or external URLs.

List scheduled events

Tool to retrieve a list of scheduled Calendly events.

List user availability schedules

Retrieves all availability schedules for the specified Calendly user.

List user busy times

Fetches a user's busy time intervals (internal and external calendar events) in ascending order for a period up to 7 days; keyset pagination is not supported.

List User Meeting Locations

Tool to retrieve configured meeting location information for a given Calendly user.

List webhook subscriptions

Retrieves webhook subscriptions for a Calendly organization; `scope` determines if `user` or `group` URI is also required for filtering.

Invite user to organization

Tool to invite a user to a Calendly organization via email.

Create Event Invitee

Tool to create a new Event Invitee with standard notifications, calendar invites, reschedules, and workflows.

Remove user from organization

Removes a user (who is not an owner) from an organization by their membership UUID, requiring administrative privileges.

Revoke a user's organization invitation

Revokes a pending and revokable (not yet accepted or expired) organization invitation using its UUID and the organization's UUID, rendering the invitation link invalid.

Update Event Type

Tool to update an existing one-on-one event type (kind: solo) in Calendly.

Update Event Type Availability

Tool to update an event type availability schedule in Calendly.

FRAMEWORKS

How to build Calendly MCP Agent with another framework

ChatGPT

Use Calendly MCP with ChatGPT

OpenAI Agents SDK

Use Calendly MCP with OpenAI Agents SDK

Claude Agent SDK

Use Calendly MCP with Claude Agent SDK

Claude Code

Use Calendly MCP with Claude Code

Claude Cowork

Use Calendly MCP with Claude Cowork

Codex

Use Calendly MCP with Codex

Cursor

Use Calendly MCP with Cursor

OpenClaw

Use Calendly MCP with OpenClaw

Hermes

Use Calendly MCP with Hermes

CLI

Use Calendly MCP with CLI

Google ADK

Use Calendly MCP with Google ADK

Vercel AI SDK

Use Calendly MCP with Vercel AI SDK

Mastra AI

Use Calendly MCP with Mastra AI

LlamaIndex

Use Calendly MCP with LlamaIndex

CrewAI

Use Calendly MCP with CrewAI

OpenCode

Use Calendly MCP with OpenCode

VS Code

Use Calendly MCP with VS Code

MORE TOOLKITS

Explore Other Toolkits

Toolkit marketplace

Google Calendar

Oauth2

Google Calendar is a time management service for scheduling meetings, events, and reminders. It streamlines personal and team organization with integrated notifications and sharing options.

Apaleo

Oauth2

Apaleo is a cloud-based property management platform for hospitality businesses. It centralizes reservations, billing, and daily operations for smoother hotel management.

Appointo

Api Key

Appointo is an appointment booking platform for Shopify stores. It lets businesses add online scheduling to their websites with zero coding.

Bart

Api Key

Bart is the Bay Area Rapid Transit system, providing fast public transportation across the San Francisco Bay Area. It helps commuters and travelers get real-time schedule info, plan routes, and stay updated on service changes.

FAQ

Frequently asked questions

With a standalone Calendly MCP server, the agents and LLMs can only access a fixed set of Calendly tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Calendly 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 Calendly tools.

Yes, absolutely. You can configure which Calendly 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 Calendly data and credentials are handled as safely as possible.

Start with Calendly.It takes 30 seconds.

Managed auth, hosted MCP servers, and every Calendly tool your agent needs.Free to start.

Start building

Customer stories

Teams ship real agents on Composio

GET STARTED FOR FREE BOOK A DEMO

Karan skipped his own birthday party to fix our critical issue. It was 10pm and he diverted his Waymo to help us instead. This really sets the bar — it shows the commitment you need when users rely on your software.

Harsha Gaddipati

Co-founder, Slashy

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.

Abhi Arya

Co-founder, Opennote

We chose Composio over Pipedream because it delivered depth where it mattered — niche tools and tricky edge cases other platforms simply ignored. That gave us confidence to scale without compromising.

Nirman Dave

CEO, Zams

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.

Ryan Yu

Founder, Extra Thursday

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.

Tomisin Jenrola

Founder & CEO, SwarmZero

With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

Jerome Leclanche

Co-Founder, Ingram Technologies

How to integrate Calendly MCP with LangChain

Connect Calendly without auth hassles

Introduction

Also integrate Calendly with

TL;DR

What is LangChain?

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

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

What is Composio SDK?

How the Composio SDK works

Step-by-step Guide

Prerequisites

Getting API Keys for OpenAI and Composio

Install dependencies

Set up environment variables

Import dependencies

Initialize Composio client

Create a Tool Router session

Configure the agent with the MCP URL

Set up interactive chat interface

Run the application

Complete Code

Conclusion

Supported Tools

How to build Calendly MCP Agent with another framework

ChatGPT

OpenAI Agents SDK

Claude Agent SDK

Claude Code

Claude Cowork

Codex

Cursor

OpenClaw

Hermes

CLI

Google ADK

Vercel AI SDK

Mastra AI

LlamaIndex

CrewAI

OpenCode

VS Code

Explore Other Toolkits

Google Calendar

Apaleo

Appointo

Bart

Frequently asked questions

What are the differences in Tool Router MCP and Calendly MCP?+

Can I use Tool Router MCP with LangChain?+

Can I manage the permissions and scopes for Calendly while using Tool Router?+

How safe is my data with Composio Tool Router?+

Start with Calendly.It takes 30 seconds.

Teams ship real agents on Composio