How to integrate Calendly MCP with Google ADK

This guide walks you through connecting Calendly to Google ADK 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 Google ADK 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 Google ADK 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 Google ADK 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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TL;DR

Here's what you'll learn:
  • Get a Calendly account set up and connected to Composio
  • Install the Google ADK and Composio packages
  • Create a Composio Tool Router session for Calendly
  • Build an agent that connects to Calendly through MCP
  • Interact with Calendly using natural language

What is Google ADK?

Google ADK (Agents Development Kit) is Google's framework for building AI agents powered by Gemini models. It provides tools for creating agents that can use external services through the Model Context Protocol.

Key features include:

  • Gemini Integration: Native support for Google's Gemini models
  • MCP Toolset: Built-in support for Model Context Protocol tools
  • Streamable HTTP: Connect to external services through streamable HTTP
  • CLI and Web UI: Run agents via command line or web interface

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:
  • A Google API key for Gemini models
  • A Composio account and API key
  • Python 3.9 or later installed
  • Basic familiarity with Python
2

Getting API Keys for Google and Composio

Google API Key
  • Go to Google AI Studio and create an API key.
  • Copy the key and keep it safe. You will put this in GOOGLE_API_KEY.
Composio API Key and User ID
  • Log in to the Composio dashboard.
  • Go to Settings → API Keys and copy your Composio API key. Use this for COMPOSIO_API_KEY.
  • Decide on a stable user identifier to scope sessions, often your email or a user ID. Use this for COMPOSIO_USER_ID.
3

Install dependencies

bash
pip install google-adk composio python-dotenv

Inside your virtual environment, install the required packages.

What's happening:

  • google-adk is Google's Agents Development Kit
  • composio connects your agent to Calendly via MCP
  • python-dotenv loads environment variables
4

Set up ADK project

bash
adk create my_agent

Set up a new Google ADK project.

What's happening:

  • This creates an agent folder with a root agent file and .env file
5

Set environment variables

bash
GOOGLE_API_KEY=your-google-api-key
COMPOSIO_API_KEY=your-composio-api-key
COMPOSIO_USER_ID=your-user-id-or-email

Save all your credentials in the .env file.

What's happening:

  • GOOGLE_API_KEY authenticates with Google's Gemini models
  • COMPOSIO_API_KEY authenticates with Composio
  • COMPOSIO_USER_ID identifies the user for session management
6

Import modules and validate environment

python
import os
import warnings

from composio import Composio
from dotenv import load_dotenv
from google.adk.agents.llm_agent import Agent
from google.adk.tools.mcp_tool.mcp_session_manager import StreamableHTTPConnectionParams
from google.adk.tools.mcp_tool.mcp_toolset import McpToolset

load_dotenv()

warnings.filterwarnings("ignore", message=".*BaseAuthenticatedTool.*")

GOOGLE_API_KEY = os.getenv("GOOGLE_API_KEY")
COMPOSIO_API_KEY = os.getenv("COMPOSIO_API_KEY")
COMPOSIO_USER_ID = os.getenv("COMPOSIO_USER_ID")

if not GOOGLE_API_KEY:
    raise ValueError("GOOGLE_API_KEY is not set in the environment.")
if not COMPOSIO_API_KEY:
    raise ValueError("COMPOSIO_API_KEY is not set in the environment.")
if not COMPOSIO_USER_ID:
    raise ValueError("COMPOSIO_USER_ID is not set in the environment.")
What's happening:
  • os reads environment variables
  • Composio is the main Composio SDK client
  • GoogleProvider declares that you are using Google ADK as the agent runtime
  • Agent is the Google ADK LLM agent class
  • McpToolset lets the ADK agent call MCP tools over HTTP
7

Create Composio client and Tool Router session

python
composio_client = Composio(api_key=COMPOSIO_API_KEY)

composio_session = composio_client.create(
    user_id=COMPOSIO_USER_ID,
    toolkits=["calendly"],
)

COMPOSIO_MCP_URL = composio_session.mcp.url,
print(f"Composio MCP URL: {COMPOSIO_MCP_URL}")
What's happening:
  • Authenticates to Composio with your API key
  • Declares Google ADK as the provider
  • Spins up a short-lived MCP endpoint for your user and selected toolkit
  • Stores the MCP HTTP URL for the ADK MCP integration
8

Set up the McpToolset and create the Agent

python
composio_toolset = McpToolset(
    connection_params=StreamableHTTPConnectionParams(
        url=COMPOSIO_MCP_URL,
        headers={"x-api-key": COMPOSIO_API_KEY}
    )
)

root_agent = Agent(
    model="gemini-2.5-flash",
    name="composio_agent",
    description="An agent that uses Composio tools to perform actions.",
    instruction=(
        "You are a helpful assistant connected to Composio. "
        "You have the following tools available: "
        "COMPOSIO_SEARCH_TOOLS, COMPOSIO_MULTI_EXECUTE_TOOL, "
        "COMPOSIO_MANAGE_CONNECTIONS, COMPOSIO_REMOTE_BASH_TOOL, COMPOSIO_REMOTE_WORKBENCH. "
        "Use these tools to help users with Calendly operations."
    ),
    tools=[composio_toolset],
)

print("\nAgent setup complete. You can now run this agent directly ;)")
What's happening:
  • Connects the ADK agent to the Composio MCP endpoint through McpToolset
  • Uses Gemini as the model powering the agent
  • Lists exact tool names in instruction to reduce misnamed tool calls
9

Run the agent

bash
# Run in CLI mode
adk run my_agent

# Or run in web UI mode
adk web

Execute the agent from the project root. The web command opens a web portal where you can chat with the agent.

What's happening:

  • adk run runs the agent in CLI mode
  • adk web . opens a web UI for interactive testing

Complete Code

Here's the complete code to get you started with Calendly and Google ADK:

python
import os
import warnings

from composio import Composio
from composio_google import GoogleProvider
from dotenv import load_dotenv
from google.adk.agents.llm_agent import Agent
from google.adk.tools.mcp_tool.mcp_session_manager import StreamableHTTPConnectionParams
from google.adk.tools.mcp_tool.mcp_toolset import McpToolset

load_dotenv()
warnings.filterwarnings("ignore", message=".*BaseAuthenticatedTool.*")

GOOGLE_API_KEY = os.getenv("GOOGLE_API_KEY")
COMPOSIO_API_KEY = os.getenv("COMPOSIO_API_KEY")
COMPOSIO_USER_ID = os.getenv("COMPOSIO_USER_ID")

if not GOOGLE_API_KEY:
    raise ValueError("GOOGLE_API_KEY is not set in the environment.")
if not COMPOSIO_API_KEY:
    raise ValueError("COMPOSIO_API_KEY is not set in the environment.")
if not COMPOSIO_USER_ID:
    raise ValueError("COMPOSIO_USER_ID is not set in the environment.")

composio_client = Composio(api_key=COMPOSIO_API_KEY, provider=GoogleProvider())

composio_session = composio_client.create(
    user_id=COMPOSIO_USER_ID,
    toolkits=["calendly"],
)

COMPOSIO_MCP_URL = composio_session.mcp.url


composio_toolset = McpToolset(
    connection_params=StreamableHTTPConnectionParams(
        url=COMPOSIO_MCP_URL,
        headers={"x-api-key": COMPOSIO_API_KEY}
    )
)

root_agent = Agent(
    model="gemini-2.5-flash",
    name="composio_agent",
    description="An agent that uses Composio tools to perform actions.",
    instruction=(
        "You are a helpful assistant connected to Composio. "
        "You have the following tools available: "
        "COMPOSIO_SEARCH_TOOLS, COMPOSIO_MULTI_EXECUTE_TOOL, "
        "COMPOSIO_MANAGE_CONNECTIONS, COMPOSIO_REMOTE_BASH_TOOL, COMPOSIO_REMOTE_WORKBENCH. "
        "Use these tools to help users with Calendly operations."
    ),  
    tools=[composio_toolset],
)

print("\nAgent setup complete. You can now run this agent directly ;)")

Conclusion

You've successfully integrated Calendly with the Google ADK through Composio's MCP Tool Router. Your agent can now interact with Calendly using natural language commands.

Key takeaways:

  • The Tool Router approach dynamically routes requests to the appropriate Calendly tools
  • Environment variables keep your credentials secure and separate from code
  • Clear agent instructions reduce tool calling errors
  • The ADK web UI provides an interactive interface for testing and development

You can extend this setup by adding more toolkits to the toolkits array in your session configuration.

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.

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. Google ADK 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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