How to integrate Square MCP with Google ADK

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Introduction

This guide walks you through connecting Square to Google ADK using the Composio tool router. By the end, you'll have a working Square agent that can create and send an invoice to a customer, list all recent payments from last week, update item prices in your product catalog through natural language commands.

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

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

Also integrate Square with

TL;DR

Here's what you'll learn:
  • Get a Square account set up and connected to Composio
  • Install the Google ADK and Composio packages
  • Create a Composio Tool Router session for Square
  • Build an agent that connects to Square through MCP
  • Interact with Square 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 Square MCP server, and what's possible with it?

The Square MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Square account. It provides structured and secure access to your Square business tools, so your agent can perform actions like processing payments, managing invoices, tracking orders, handling customers, and managing inventory on your behalf.

  • Seamless payment processing: Let your agent accept card payments, issue refunds, and manage transactions across your business locations.
  • Automated invoice creation and management: Ask your agent to generate, send, and monitor invoices for your customers, streamlining your billing process.
  • Order and fulfillment tracking: Enable your agent to view, update, and manage orders, helping you keep tabs on fulfillment and delivery status with ease.
  • Customer profile management: Have your agent create, update, or search customer profiles, making it easier to personalize service and maintain up-to-date records.
  • Inventory and item catalog control: Allow your agent to track stock levels, update item details, and organize your catalog for smooth retail operations.

Supported Tools & Triggers

Tools
Accept DisputeAccept a dispute and acknowledge liability, returning funds to the cardholder.
Add Group to CustomerTool to add a customer to a customer group.
Calculate OrderTool to preview order pricing without creating an order.
Cancel InvoiceCancels a Square invoice, preventing further payments from being collected.
Cancel PaymentCancels (voids) a payment that is in APPROVED status.
Create Bulk CustomersTool to create multiple customer profiles in a single request.
Create CardTool to create a card on file.
Create CustomerTool to create a new customer profile in Square.
Create Customer Custom Attribute DefinitionTool to create a customer-related custom attribute definition.
Create Customer GroupTool to create a new customer group for a business.
Create Dispute Evidence FileTool to upload a file as dispute evidence.
Create Dispute Evidence TextUpload text evidence for a dispute challenge.
Create Invoice AttachmentUpload and attach a file to a Square invoice.
Create LocationTool to create a new business location in a Square account.
Create Location Custom Attribute DefinitionTool to create a location-related custom attribute definition.
Delete CustomerTool to delete a Square customer profile.
Delete Customer Custom AttributeTool to delete a custom attribute from a customer profile.
Delete Customer Custom Attribute DefinitionTool to delete a customer-related custom attribute definition.
Delete Customer GroupTool to delete a customer group by its ID.
Bulk Delete CustomersTool to bulk delete customer profiles from Square.
Delete Dispute EvidenceRemoves a specific piece of evidence from a dispute.
Delete InvoiceTool to delete a Square invoice (only DRAFT invoices can be deleted).
Delete Invoice AttachmentTool to delete an attachment from a Square invoice.
Delete Location Custom AttributeTool to delete a custom attribute from a location.
Delete Location Custom Attribute DefinitionTool to delete a location-related custom attribute definition.
Delete Locations Custom Attributes (Batch)Tool to delete custom attributes from multiple locations in a single batch request.
Delete Merchant Custom AttributeTool to delete a custom attribute from a merchant profile.
Delete Merchant Custom Attribute DefinitionTool to delete a merchant-related custom attribute definition.
Delete Merchants Custom Attributes (Batch)Tool to delete custom attributes from multiple merchants in a single batch request.
Delete Webhook SubscriptionPermanently deletes a webhook subscription by its ID.
Get Business Booking ProfileTool to retrieve the business booking profile for a Square merchant via GraphQL.
Get Current MerchantTool to retrieve merchant information associated with the access token using Square's GraphQL API.
Get Customer Custom AttributeRetrieves a custom attribute from a customer profile in Square.
Get Customer Custom Attribute DefinitionTool to retrieve a customer-related custom attribute definition from Square.
Get Customers via GraphQLTool to retrieve customer profiles from Square Customer Directory using GraphQL API.
Get Dispute EvidenceRetrieves detailed information about a specific piece of evidence that was uploaded for a dispute.
Get InvoiceRetrieves detailed information about a specific Square invoice by its ID.
Get MerchantTool to retrieve detailed information about a specific Square merchant by ID.
Get Online Checkout Location SettingsTool to retrieve location-level settings for Square online checkout.
List ChannelsTool to list requested channels from Square.
List Customer Custom Attribute DefinitionsTool to list customer-related custom attribute definitions from Square.
List Customer Custom Attribute Definitions (GraphQL)Tool to retrieve customer custom attribute definitions via Square's GraphQL API.
List Customer Custom AttributesTool to list custom attributes for a customer profile.
List Customer GroupsTool to retrieve the list of customer groups of a business.
List CustomersTool to retrieve customer profiles associated with a Square account.
List Customer SegmentsTool to retrieve the list of customer segments of a business.
List Dispute EvidenceTool to list evidence items associated with a given dispute.
List InvoicesTool to list invoices for a Square location.
List Location Custom Attribute DefinitionsTool to list location-related custom attribute definitions from Square.
List LocationsTool to retrieve all business locations from a Square account.
List Locations Custom AttributesTool to list custom attributes for a specific location in Square.
List Merchant Custom Attribute DefinitionsTool to list merchant-related custom attribute definitions from Square.
List MerchantsTool to retrieve merchant account information associated with the access token.
List Merchants Custom AttributesTool to list custom attributes for a specific merchant in Square.
List PaymentsTool to list payments by location and time range to enable reconciliation and net sales reporting from Square POS.
List Webhook Event TypesTool to list available webhook event types.
List Webhook SubscriptionsList all webhook subscriptions owned by your application.
Remove Group From CustomerRemoves a customer from a customer group.
Retrieve Bulk CustomersTool to retrieve multiple customer profiles in a single request.
Retrieve ChannelRetrieve a Square channel by its ID.
Bulk Retrieve ChannelsTool to bulk retrieve multiple Square channels by their IDs in a single request.
Retrieve CustomerTool to retrieve detailed information about a specific Square customer by ID.
Retrieve Customer GroupTool to retrieve a specific Square customer group by ID.
Retrieve Customer SegmentTool to retrieve a specific customer segment by its ID.
Retrieve DisputeTool to retrieve a Square dispute by ID.
Retrieve LocationTool to retrieve detailed information about a specific Square location by ID.
Retrieve Location Custom AttributeRetrieves a custom attribute associated with a location in Square.
Retrieve Location Custom Attribute DefinitionTool to retrieve a location-related custom attribute definition.
Retrieve Merchant Custom AttributeRetrieves a custom attribute associated with a merchant in Square.
Retrieve Merchant Custom Attribute DefinitionTool to retrieve a merchant-related custom attribute definition from Square.
Retrieve MerchantsTool to retrieve merchant information including status, main location details, and capabilities using Square's GraphQL API.
Retrieve OrderRetrieves detailed information about a specific Square order by its ID.
Retrieve Payment LinkRetrieves a Square-hosted payment link by ID.
Retrieve Token StatusTool to retrieve information about an OAuth access token or personal access token.
Retrieve Webhook SubscriptionRetrieve a Square webhook subscription by its ID.
Search CustomersTool to search customer profiles in Square Customer Directory.
Search OrdersTool to search orders across one or more Square locations with filters.
Submit Dispute EvidenceSubmits evidence for a dispute to the cardholder's bank.
Test Webhook SubscriptionTests a webhook subscription by sending a test event to the configured notification URL.
Update CustomerTool to update an existing Square customer profile.
Update Customer Custom Attribute DefinitionTool to update a customer-related custom attribute definition in Square.
Update Customer GroupTool to update a customer group's information by its ID.
Bulk Update CustomersTool to update multiple customer profiles in a single batch operation.
Update LocationTool to update an existing business location in a Square account.
Update Location Custom Attribute DefinitionTool to update a location-related custom attribute definition in Square.
Update Merchant Custom Attribute DefinitionTool to update a merchant-related custom attribute definition in Square.
Update Online Checkout Location SettingsTool to update location-level settings for Square online checkout.
Update OrderUpdates an existing Square order by adding, modifying, or removing fields.
Update Webhook SubscriptionTool to update a Square webhook subscription.
Update Webhook Subscription Signature KeyTool to rotate the signature key for a webhook subscription.
Upsert Customer Custom AttributeTool to create or update a custom attribute for a customer profile.
Batch Upsert Customer Custom AttributesTool to create or update custom attributes for multiple customers in a single batch request.
Upsert Location Custom AttributeTool to create or update a custom attribute for a location.
Batch Upsert Locations Custom AttributesTool to create or update custom attributes for multiple locations in a single batch request.
Upsert Merchant Custom AttributeTool to create or update a custom attribute for a merchant profile.
Batch Upsert Merchants Custom AttributesTool to create or update custom attributes for multiple merchants in a single batch request.

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

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 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 Square via MCP
  • 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 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
composio_client = Composio(api_key=COMPOSIO_API_KEY)

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

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

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 Square 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 Square 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=["square"],
)

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 Square operations."
    ),  
    tools=[composio_toolset],
)

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

Conclusion

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

Key takeaways:

  • The Tool Router approach dynamically routes requests to the appropriate Square 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 Square MCP Agent with another framework

FAQ

What are the differences in Tool Router MCP and Square MCP?

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

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

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

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