How to integrate Calendly MCP with Google ADK

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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 my next meeting, cancel my 2pm event with a reason, mark an invitee as no-show for today's appointment, delete all invitee data for privacy compliance 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.

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.

Supported Tools & Triggers

Tools
Cancel eventPermanently cancels an existing, active scheduled event by its `uuid`, optionally providing a `reason`, which may trigger notifications to invitees.
Create an invitee no-showMarks an invitee, identified by their existing and valid uri, as a 'no show' for a scheduled event.
Create One-Off Event TypeCreates 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 linkCreate a single-use scheduling link.
Create shareCreates a customizable, one-time share link for a calendly event type, allowing specific overrides to its settings (e.
Create single use scheduling linkCreates a one-time, single-use scheduling link for an active calendly event type, expiring after one booking.
Create webhook subscriptionCreates a calendly webhook subscription to notify a specified `url` (which must be a publicly accessible https endpoint) for selected `events` within a given `organization` and `scope`.
Delete invitee dataPermanently 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 showDeletes 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 scheduled event dataFor 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 subscriptionDeletes an existing webhook subscription to stop calendly sending event notifications to its registered callback url; this operation is idempotent.
Get current userRetrieves detailed information about the currently authenticated calendly user.
Get eventUse to retrieve a specific calendly scheduled event by its uuid, provided the event exists in the user's calendly account.
Get event inviteeRetrieves detailed information about a specific invitee of a scheduled event, using their unique uuids.
Get event typeRetrieves details for a specific calendly event type, identified by its uuid, which must be valid and correspond to an existing event type.
Get groupRetrieves all attributes of a specific calendly group by its uuid; the group must exist.
Get group relationshipRetrieves a specific calendly group relationship by its valid and existing uuid, providing details on user-group associations and membership.
Get invitee no showRetrieves 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 invitationRetrieves a specific calendly organization invitation using its uuid and the parent organization's uuid.
Get organization membershipRetrieves a specific calendly organization membership by its uuid, returning all its attributes.
Get routing formRetrieves a specific routing form by its uuid, providing its configuration details including questions and routing logic.
Get userRetrieves comprehensive details for an existing calendly user.
Get user availability scheduleRetrieves an existing user availability schedule by its uuid; this schedule defines the user's default hours of availability.
Get webhook subscriptionRetrieves the details of an existing webhook subscription, identified by its uuid, including its callback url, subscribed events, scope, and state.
Invite user to organizationInvites a user to the specified calendly organization by email, if they aren't already a member and lack a pending invitation to it.
List activity log entriesRetrieves a list of activity log entries for a specified calendly organization (requires an active enterprise subscription), supporting filtering, sorting, and pagination.
List event inviteesRetrieves a list of invitees for a specified calendly event uuid, with options to filter by status or email, and sort by creation time.
List eventsRetrieves a list of scheduled calendly events; requires `user`, `organization`, `group`, or `invitee email` for scope, and admin rights may be needed when filtering by `organization` or `group`.
List event type available timesFetches available time slots for a calendly event type within a specified time range; results are not paginated.
List event type hostsRetrieves a list of hosts (users) assigned to a specific, existing calendly event type, identified by its uri.
List group relationshipsRetrieves a list of group relationships defining an owner's role (e.
List groupsReturns a list of groups for a specified calendly organization uri, supporting pagination.
List organization invitationsRetrieves a list of invitations for a specific organization, identified by its uuid.
List organization membershipsRetrieves a list of organization memberships.
List outgoing communicationsRetrieves 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 formsRetrieves routing forms for a specified organization; routing forms are questionnaires used to direct invitees to appropriate booking pages or external urls.
List user availability schedulesRetrieves all availability schedules for the specified calendly user.
List user busy timesFetches 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 event typesRetrieves event types for a user or organization; requires either the `user` or `organization` uri.
List webhook subscriptionsRetrieves webhook subscriptions for a calendly organization; `scope` determines if `user` or `group` uri is also required for filtering.
Remove user from organizationRemoves a user (who is not an owner) from an organization by their membership uuid, requiring administrative privileges.
Revoke a user's organization invitationRevokes a pending and revokable (not yet accepted or expired) organization invitation using its uuid and the organization's uuid, rendering the invitation link invalid.

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

What is Tool Router?

Composio's Tool Router 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 Tool Router

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

How the Tool Router works

The Tool Router 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

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

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.

Install dependencies

bash
pip install google-adk composio-google 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
  • composio-google provides the Google ADK provider
  • python-dotenv loads environment variables

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

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

Import modules and validate environment

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.")
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

Create Composio client and Tool Router session

python
print("Initializing Composio client...")
composio_client = Composio(api_key=COMPOSIO_API_KEY, provider=GoogleProvider())

print("Creating Composio session...")
composio_session = composio_client.create(
    user_id=COMPOSIO_USER_ID,
    toolkits=["calendly"],
)

COMPOSIO_MCP_URL = composio_session.mcp.url
print(f"Composio MCP HTTP 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

Set up the McpToolset and create the Agent

python
print("Creating Composio toolset for the agent...")
composio_toolset = McpToolset(
    connection_params=StreamableHTTPConnectionParams(
        url=COMPOSIO_MCP_URL,
        headers={"x-api-key": os.getenv("COMPOSIO_API_KEY")}
    )
)

root_agent = Agent(
    model="gemini-2.5-pro",
    name="composio_agent",
    description="An agent that uses Calendly 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

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

def main():
    try:
        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.")

        print("Initializing Composio client...")
        composio_client = Composio(api_key=COMPOSIO_API_KEY, provider=GoogleProvider())

        print("Creating Composio session...")
        composio_session = composio_client.create(
            user_id=COMPOSIO_USER_ID,
            toolkits=["calendly"],
        )

        COMPOSIO_MCP_URL = composio_session.mcp.url
        print(f"Composio MCP HTTP URL: {COMPOSIO_MCP_URL}")

        print("Creating Composio toolset for the agent...")
        composio_toolset = McpToolset(
            connection_params=StreamableHTTPConnectionParams(
                url=COMPOSIO_MCP_URL,
                headers={"x-api-key": os.getenv("COMPOSIO_API_KEY")}
            )
        )

        root_agent = Agent(
            model="gemini-2.5-pro",
            name="composio_agent",
            description="An agent that uses Calendly 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 ;)")

    except Exception as e:
        print(f"\nAn error occurred during agent setup: {e}")

if __name__ == "__main__":
    main()

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.

How to build Calendly MCP Agent with another framework

FAQ

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.

Can I use Tool Router MCP with Google ADK?

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.

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.

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.

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