How to integrate Calendarhero MCP with Mastra AI

This guide walks you through connecting Calendarhero to Mastra AI 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 Mastra AI 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 Mastra AI 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 Mastra AI 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 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 Calendarhero tools
  • Connect Mastra's MCP client to the Composio generated MCP URL
  • Fetch Calendarhero 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 Calendarhero 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 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 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 Calendarhero 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 Calendarhero

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

  const composioMCPUrl = session.mcp.url;
  console.log("Calendarhero MCP URL:", composioMCPUrl);
What's happening:
  • create spins up a short-lived MCP HTTP endpoint for this user
  • The toolkits array contains "calendarhero" for Calendarhero 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 Calendarhero toolkit
8

Create the Mastra agent

typescript
const agent = new Agent({
    name: "calendarhero-mastra-agent",
    instructions: "You are an AI agent with Calendarhero 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: {
        calendarhero: 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 Calendarhero 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 Calendarhero 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: ["calendarhero"],
  });

  const composioMCPUrl = session.mcp.url;

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

  const composioTools = await mcpClient.getTools();

  const agent = new Agent({
    name: "calendarhero-mastra-agent",
    instructions: "You are an AI agent with Calendarhero 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: { calendarhero: 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 Calendarhero 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 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

LangChain logo

LangChain

Use Calendarhero MCP with LangChain

Vercel AI SDK logo

Vercel AI SDK

Use Calendarhero MCP with Vercel AI SDK

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. 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 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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