How to integrate Square MCP with LlamaIndex

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Introduction

This guide walks you through connecting Square to LlamaIndex 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 LlamaIndex 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:
  • Set your OpenAI and Composio API keys
  • Install LlamaIndex and Composio packages
  • Create a Composio Tool Router session for Square
  • Connect LlamaIndex to the Square MCP server
  • Build a Square-powered agent using LlamaIndex
  • Interact with Square through natural language

What is LlamaIndex?

LlamaIndex is a data framework for building LLM applications. It provides tools for connecting LLMs to external data sources and services through agents and tools.

Key features include:

  • ReAct Agent: Reasoning and acting pattern for tool-using agents
  • MCP Tools: Native support for Model Context Protocol
  • Context Management: Maintain conversation context across interactions
  • Async Support: Built for async/await patterns

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 you begin, make sure you have:
  • Python 3.8/Node 16 or higher installed
  • A Composio account with the API key
  • An OpenAI API key
  • A Square account and project
  • Basic familiarity with async Python/Typescript

Getting API Keys for OpenAI, Composio, and Square

OpenAI API key (OPENAI_API_KEY)
  • Go to the OpenAI dashboard
  • Create an API key if you don't have one
  • Assign it to OPENAI_API_KEY in .env
Composio API key and user ID
  • Log into the Composio dashboard
  • Copy your API key from Settings
    • Use this as COMPOSIO_API_KEY
  • Pick a stable user identifier (email or ID)
    • Use this as COMPOSIO_USER_ID

Installing dependencies

pip install composio-llamaindex llama-index llama-index-llms-openai llama-index-tools-mcp python-dotenv

Create a new Python project and install the necessary dependencies:

  • composio-llamaindex: Composio's LlamaIndex integration
  • llama-index: Core LlamaIndex framework
  • llama-index-llms-openai: OpenAI LLM integration
  • llama-index-tools-mcp: MCP client for LlamaIndex
  • python-dotenv: Environment variable management

Set environment variables

bash
OPENAI_API_KEY=your-openai-api-key
COMPOSIO_API_KEY=your-composio-api-key
COMPOSIO_USER_ID=your-user-id

Create a .env file in your project root:

These credentials will be used to:

  • Authenticate with OpenAI's GPT-5 model
  • Connect to Composio's Tool Router
  • Identify your Composio user session for Square access

Import modules

import asyncio
import os
import dotenv

from composio import Composio
from composio_llamaindex import LlamaIndexProvider
from llama_index.core.agent.workflow import ReActAgent
from llama_index.core.workflow import Context
from llama_index.llms.openai import OpenAI
from llama_index.tools.mcp import BasicMCPClient, McpToolSpec

dotenv.load_dotenv()

Create a new file called square_llamaindex_agent.py and import the required modules:

Key imports:

  • asyncio: For async/await support
  • Composio: Main client for Composio services
  • LlamaIndexProvider: Adapts Composio tools for LlamaIndex
  • ReActAgent: LlamaIndex's reasoning and action agent
  • BasicMCPClient: Connects to MCP endpoints
  • McpToolSpec: Converts MCP tools to LlamaIndex format

Load environment variables and initialize Composio

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

if not OPENAI_API_KEY:
    raise ValueError("OPENAI_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:

This ensures missing credentials cause early, clear errors before the agent attempts to initialise.

Create a Tool Router session and build the agent function

async def build_agent() -> ReActAgent:
    composio_client = Composio(
        api_key=COMPOSIO_API_KEY,
        provider=LlamaIndexProvider(),
    )

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

    mcp_url = session.mcp.url
    print(f"Composio MCP URL: {mcp_url}")

    mcp_client = BasicMCPClient(mcp_url, headers={"x-api-key": COMPOSIO_API_KEY})
    mcp_tool_spec = McpToolSpec(client=mcp_client)
    tools = await mcp_tool_spec.to_tool_list_async()

    llm = OpenAI(model="gpt-5")

    description = "An agent that uses Composio Tool Router MCP tools to perform Square actions."
    system_prompt = """
    You are a helpful assistant connected to Composio Tool Router.
    Use the available tools to answer user queries and perform Square actions.
    """
    return ReActAgent(tools=tools, llm=llm, description=description, system_prompt=system_prompt, verbose=True)

What's happening here:

  • We create a Composio client using your API key and configure it with the LlamaIndex provider
  • We then create a tool router MCP session for your user, specifying the toolkits we want to use (in this case, square)
  • The session returns an MCP HTTP endpoint URL that acts as a gateway to all your configured tools
  • LlamaIndex will connect to this endpoint to dynamically discover and use the available Square tools.
  • The MCP tools are mapped to LlamaIndex-compatible tools and plug them into the Agent.

Create an interactive chat loop

async def chat_loop(agent: ReActAgent) -> None:
    ctx = Context(agent)
    print("Type 'quit', 'exit', or Ctrl+C to stop.")

    while True:
        try:
            user_input = input("\nYou: ").strip()
        except (KeyboardInterrupt, EOFError):
            print("\nBye!")
            break

        if not user_input or user_input.lower() in {"quit", "exit"}:
            print("Bye!")
            break

        try:
            print("Agent: ", end="", flush=True)
            handler = agent.run(user_input, ctx=ctx)

            async for event in handler.stream_events():
                # Stream token-by-token from LLM responses
                if hasattr(event, "delta") and event.delta:
                    print(event.delta, end="", flush=True)
                # Show tool calls as they happen
                elif hasattr(event, "tool_name"):
                    print(f"\n[Using tool: {event.tool_name}]", flush=True)

            # Get final response
            response = await handler
            print()  # Newline after streaming
        except KeyboardInterrupt:
            print("\n[Interrupted]")
            continue
        except Exception as e:
            print(f"\nError: {e}")

What's happening here:

  • We're creating a direct terminal interface to chat with your Square database
  • The LLM's responses are streamed to the CLI for faster interaction.
  • The agent uses context to maintain conversation history
  • You can type 'quit' or 'exit' to stop the chat loop gracefully
  • Agent responses and any errors are displayed in a clear, readable format

Define the main entry point

async def main() -> None:
    agent = await build_agent()
    await chat_loop(agent)

if __name__ == "__main__":
    # Handle Ctrl+C gracefully
    signal.signal(signal.SIGINT, lambda s, f: (print("\nBye!"), exit(0)))
    try:
        asyncio.run(main())
    except KeyboardInterrupt:
        print("\nBye!")

What's happening here:

  • We're orchestrating the entire application flow
  • The agent gets built with proper error handling
  • Then we kick off the interactive chat loop so you can start talking to Square

Run the agent

npx ts-node llamaindex-agent.ts

When prompted, authenticate and authorise your agent with Square, then start asking questions.

Complete Code

Here's the complete code to get you started with Square and LlamaIndex:

import asyncio
import os
import signal
import dotenv

from composio import Composio
from composio_llamaindex import LlamaIndexProvider
from llama_index.core.agent.workflow import ReActAgent
from llama_index.core.workflow import Context
from llama_index.llms.openai import OpenAI
from llama_index.tools.mcp import BasicMCPClient, McpToolSpec

dotenv.load_dotenv()

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

if not OPENAI_API_KEY:
    raise ValueError("OPENAI_API_KEY is not set")
if not COMPOSIO_API_KEY:
    raise ValueError("COMPOSIO_API_KEY is not set")
if not COMPOSIO_USER_ID:
    raise ValueError("COMPOSIO_USER_ID is not set")

async def build_agent() -> ReActAgent:
    composio_client = Composio(
        api_key=COMPOSIO_API_KEY,
        provider=LlamaIndexProvider(),
    )

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

    mcp_url = session.mcp.url
    print(f"Composio MCP URL: {mcp_url}")

    mcp_client = BasicMCPClient(mcp_url, headers={"x-api-key": COMPOSIO_API_KEY})
    mcp_tool_spec = McpToolSpec(client=mcp_client)
    tools = await mcp_tool_spec.to_tool_list_async()

    llm = OpenAI(model="gpt-5")
    description = "An agent that uses Composio Tool Router MCP tools to perform Square actions."
    system_prompt = """
    You are a helpful assistant connected to Composio Tool Router.
    Use the available tools to answer user queries and perform Square actions.
    """
    return ReActAgent(
        tools=tools,
        llm=llm,
        description=description,
        system_prompt=system_prompt,
        verbose=True,
    );

async def chat_loop(agent: ReActAgent) -> None:
    ctx = Context(agent)
    print("Type 'quit', 'exit', or Ctrl+C to stop.")

    while True:
        try:
            user_input = input("\nYou: ").strip()
        except (KeyboardInterrupt, EOFError):
            print("\nBye!")
            break

        if not user_input or user_input.lower() in {"quit", "exit"}:
            print("Bye!")
            break

        try:
            print("Agent: ", end="", flush=True)
            handler = agent.run(user_input, ctx=ctx)

            async for event in handler.stream_events():
                # Stream token-by-token from LLM responses
                if hasattr(event, "delta") and event.delta:
                    print(event.delta, end="", flush=True)
                # Show tool calls as they happen
                elif hasattr(event, "tool_name"):
                    print(f"\n[Using tool: {event.tool_name}]", flush=True)

            # Get final response
            response = await handler
            print()  # Newline after streaming
        except KeyboardInterrupt:
            print("\n[Interrupted]")
            continue
        except Exception as e:
            print(f"\nError: {e}")

async def main() -> None:
    agent = await build_agent()
    await chat_loop(agent)

if __name__ == "__main__":
    # Handle Ctrl+C gracefully
    signal.signal(signal.SIGINT, lambda s, f: (print("\nBye!"), exit(0)))
    try:
        asyncio.run(main())
    except KeyboardInterrupt:
        print("\nBye!")

Conclusion

You've successfully connected Square to LlamaIndex through Composio's Tool Router MCP layer. Key takeaways:
  • Tool Router dynamically exposes Square tools through an MCP endpoint
  • LlamaIndex's ReActAgent handles reasoning and orchestration; Composio handles integrations
  • The agent becomes more capable without increasing prompt size
  • Async Python provides clean, efficient execution of agent workflows
You can easily extend this to other toolkits like Gmail, Notion, Stripe, GitHub, and more by adding them to the toolkits parameter.

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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 LlamaIndex?

Yes, you can. LlamaIndex 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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