How to integrate Calendly MCP with Mastra AI

This guide walks you through connecting Calendly to Mastra AI 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 Mastra AI 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 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.

51 Tools

Introduction

This guide walks you through connecting Calendly to Mastra AI 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 Mastra AI 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

ChatGPTOpenAI Agents SDKClaude Agent SDKClaude CodeClaude CoworkCodexOpenCodeCursorVS CodeOpenClawHermesCLIGoogle ADKLangChainVercel AI SDKLlamaIndexCrewAI

TL;DR

Here's what you'll learn:
  • Set up your environment so Mastra, OpenAI, and Composio work together
  • Create a Tool Router session in Composio that exposes Calendly tools
  • Connect Mastra's MCP client to the Composio generated MCP URL
  • Fetch Calendly tool definitions and attach them as a toolset
  • Build a Mastra agent that can reason, call tools, and return structured results
  • Run an interactive CLI where you can chat with your Calendly agent

What is Mastra AI?

Mastra AI is a TypeScript framework for building AI agents with tool support. It provides a clean API for creating agents that can use external services through MCP.

Key features include:

  • MCP Client: Built-in support for Model Context Protocol servers
  • Toolsets: Organize tools into logical groups
  • Step Callbacks: Monitor and debug agent execution
  • OpenAI Integration: Works with OpenAI models via @ai-sdk/openai

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:

  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 step09 STEPS
1

Prerequisites

Before starting, make sure you have:
  • Node.js 18 or higher
  • A Composio account with an active API key
  • An OpenAI API key
  • Basic familiarity with TypeScript
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key.
  • You need credits or a connected billing setup to use the models.
  • Store the key somewhere safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Go to Settings and copy your API key.
  • This key lets your Mastra agent talk to Composio and reach Calendly through MCP.
3

Install dependencies

bash
npm install @composio/core @mastra/core @mastra/mcp @ai-sdk/openai dotenv

Install the required packages.

What's happening:

  • @composio/core is the Composio SDK for creating MCP sessions
  • @mastra/core provides the Agent class
  • @mastra/mcp is Mastra's MCP client
  • @ai-sdk/openai is the model wrapper for OpenAI
  • dotenv loads environment variables from .env
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
COMPOSIO_USER_ID=your_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
  • COMPOSIO_USER_ID tells Composio which user this session belongs to
  • OPENAI_API_KEY lets the Mastra agent call OpenAI models
5

Import libraries and validate environment

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({
  apiKey: composioAPIKey as string,
});
What's happening:
  • dotenv/config auto loads your .env so process.env.* is available
  • openai gives you a Mastra compatible model wrapper
  • Agent is the Mastra agent that will call tools and produce answers
  • MCPClient connects Mastra to your Composio MCP server
  • Composio is used to create a Tool Router session
6

Create a Tool Router session for Calendly

typescript
async function main() {
  const session = await composio.create(
    composioUserID as string,
    {
      toolkits: ["calendly"],
    },
  );

  const composioMCPUrl = session.mcp.url;
  console.log("Calendly MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "calendly" for Calendly access
  • session.mcp.url is the MCP URL that Mastra's MCPClient will connect to
7

Configure Mastra MCP client and fetch tools

typescript
const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      nasdaq: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

console.log("Fetching MCP tools from Composio...");
const composioTools = await mcpClient.getTools();
console.log("Number of tools:", Object.keys(composioTools).length);
What's happening:
  • MCPClient takes an id for this client and a list of MCP servers
  • The headers property includes the x-api-key for authentication
  • getTools fetches the tool definitions exposed by the Calendly toolkit
8

Create the Mastra agent

typescript
const agent = new Agent({
    name: "calendly-mastra-agent",
    instructions: "You are an AI agent with Calendly tools via Composio.",
    model: "openai/gpt-5",
  });
What's happening:
  • Agent is the core Mastra agent
  • name is just an identifier for logging and debugging
  • instructions guide the agent to use tools instead of only answering in natural language
  • model uses openai("gpt-5") to configure the underlying LLM
9

Set up interactive chat interface

typescript
let messages: AiMessageType[] = [];

console.log("Chat started! Type 'exit' or 'quit' to end.\n");

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

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;
  }

  messages.push({
    id: crypto.randomUUID(),
    role: "user",
    content: trimmedInput,
  });

  console.log("\nAgent is thinking...\n");

  try {
    const response = await agent.generate(messages, {
      toolsets: {
        calendly: composioTools,
      },
      maxSteps: 8,
    });

    const { text } = response;

    if (text && text.trim().length > 0) {
      console.log(`Agent: ${text}\n`);
        messages.push({
          id: crypto.randomUUID(),
          role: "assistant",
          content: text,
        });
      }
    } catch (error) {
      console.error("\nError:", error);
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    console.log("\nSession ended.");
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main().catch((err) => {
  console.error("Fatal error:", err);
  process.exit(1);
});
What's happening:
  • messages keeps the full conversation history in Mastra's expected format
  • agent.generate runs the agent with conversation history and Calendly toolsets
  • maxSteps limits how many tool calls the agent can take in a single run
  • onStepFinish is a hook that prints intermediate steps for debugging

Complete Code

Here's the complete code to get you started with Calendly and Mastra AI:

typescript
import "dotenv/config";
import { openai } from "@ai-sdk/openai";
import { Agent } from "@mastra/core/agent";
import { MCPClient } from "@mastra/mcp";
import { Composio } from "@composio/core";
import * as readline from "readline";

import type { AiMessageType } from "@mastra/core/agent";

const openaiAPIKey = process.env.OPENAI_API_KEY;
const composioAPIKey = process.env.COMPOSIO_API_KEY;
const composioUserID = process.env.COMPOSIO_USER_ID;

if (!openaiAPIKey) throw new Error("OPENAI_API_KEY is not set");
if (!composioAPIKey) throw new Error("COMPOSIO_API_KEY is not set");
if (!composioUserID) throw new Error("COMPOSIO_USER_ID is not set");

const composio = new Composio({ apiKey: composioAPIKey as string });

async function main() {
  const session = await composio.create(composioUserID as string, {
    toolkits: ["calendly"],
  });

  const composioMCPUrl = session.mcp.url;

  const mcpClient = new MCPClient({
    id: composioUserID as string,
    servers: {
      calendly: {
        url: new URL(composioMCPUrl),
        requestInit: {
          headers: session.mcp.headers,
        },
      },
    },
    timeout: 30_000,
  });

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "calendly-mastra-agent",
    instructions: "You are an AI agent with Calendly tools via Composio.",
    model: "openai/gpt-5",
  });

  let messages: AiMessageType[] = [];

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

  rl.prompt();

  rl.on("line", async (input: string) => {
    const trimmed = input.trim();
    if (["exit", "quit"].includes(trimmed.toLowerCase())) {
      rl.close();
      return;
    }

    messages.push({ id: crypto.randomUUID(), role: "user", content: trimmed });

    const { text } = await agent.generate(messages, {
      toolsets: { calendly: composioTools },
      maxSteps: 8,
    });

    if (text) {
      console.log(`Agent: ${text}\n`);
      messages.push({ id: crypto.randomUUID(), role: "assistant", content: text });
    }

    rl.prompt();
  });

  rl.on("close", async () => {
    await mcpClient.disconnect();
    process.exit(0);
  });
}

main();

Conclusion

You've built a Mastra AI agent that can interact with Calendly through Composio's Tool Router. You can extend this further by:
  • Adding other toolkits like Gmail, Slack, or GitHub
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-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 logo

ChatGPT

Use Calendly MCP with ChatGPT

OpenAI Agents SDK logo

OpenAI Agents SDK

Use Calendly MCP with OpenAI Agents SDK

Claude Agent SDK logo

Claude Agent SDK

Use Calendly MCP with Claude Agent SDK

Claude Code logo

Claude Code

Use Calendly MCP with Claude Code

Claude Cowork logo

Claude Cowork

Use Calendly MCP with Claude Cowork

Codex logo

Codex

Use Calendly MCP with Codex

Cursor logo

Cursor

Use Calendly MCP with Cursor

OpenClaw logo

OpenClaw

Use Calendly MCP with OpenClaw

Hermes logo

Hermes

Use Calendly MCP with Hermes

CLI logo

CLI

Use Calendly MCP with CLI

Google ADK logo

Google ADK

Use Calendly MCP with Google ADK

LangChain logo

LangChain

Use Calendly MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Calendly MCP with Vercel AI SDK

LlamaIndex logo

LlamaIndex

Use Calendly MCP with LlamaIndex

CrewAI logo

CrewAI

Use Calendly MCP with CrewAI

OpenCode logo

OpenCode

Use Calendly MCP with OpenCode

VS Code logo

VS Code

Use Calendly MCP with VS Code

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. Mastra AI 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.

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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.

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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.

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