How to integrate Square MCP with OpenAI Agents SDK

This guide walks you through connecting Square to the OpenAI Agents SDK 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 OpenAI Agents SDK 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.

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Square

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Square is a platform for payment processing, POS, invoicing, and e-commerce. It empowers businesses to accept payments, manage sales, and streamline operations from one place.

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Introduction

This guide will help you understand how to give your OpenAI Agents SDK 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

Claude Agent SDK Claude Code Claude Cowork Codex OpenClaw Hermes CLI Google ADK LangChain Vercel AI SDK Mastra AI LlamaIndex CrewAI

TL;DR

Here's what you'll learn:

Get and set up your OpenAI and Composio API keys
Install the necessary dependencies
Initialize Composio and create a Tool Router session for Square
Configure an AI agent that can use Square as a tool
Run a live chat session where you can ask the agent to perform Square operations

What is OpenAI Agents SDK?

The OpenAI Agents SDK is a lightweight framework for building AI agents that can use tools and maintain conversation state. It provides a simple interface for creating agents with hosted MCP tool support.

Key features include:

Hosted MCP Tools: Connect to external services through hosted MCP endpoints
SQLite Sessions: Persist conversation history across interactions
Simple API: Clean interface with Agent, Runner, and tool configuration
Streaming Support: Real-time response streaming for interactive applications

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.

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:

Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Step by step09 STEPS

Prerequisites

Before starting, make sure you have:

Composio API Key and OpenAI API Key
Primary know-how of OpenAI Agents SDK
A live Square project
Some knowledge of Python or Typescript

Getting API Keys for OpenAI and Composio

OpenAI API Key

Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
Keep the API key safe.

Composio API Key

Log in to the Composio dashboard.
Go to Settings and copy your API key.

Install dependencies

npm install @composio/openai-agents @openai/agents dotenv

Install the Composio SDK and the OpenAI Agents SDK.

Set up environment variables

bash

OPENAI_API_KEY=sk-...your-api-key
COMPOSIO_API_KEY=your-api-key
USER_ID=composio_user@gmail.com

Create a .env file and add your OpenAI and Composio API keys.

Import dependencies

import 'dotenv/config';
import { Composio } from '@composio/core';
import { OpenAIAgentsProvider } from '@composio/openai-agents';
import { Agent, hostedMcpTool, run, OpenAIConversationsSession } from '@openai/agents';
import * as readline from 'readline';

What's happening:

You're importing all necessary libraries.
The Composio and OpenAIAgentsProvider classes are imported to connect your OpenAI agent to Composio tools like Square.

Set up the Composio instance

dotenv.config();

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.USER_ID;

if (!composioApiKey) {
  throw new Error('COMPOSIO_API_KEY is not set. Create a .env file with COMPOSIO_API_KEY=your_key');
}
if (!userId) {
  throw new Error('USER_ID is not set');
}

// Initialize Composio
const composio = new Composio({
  apiKey: composioApiKey,
  provider: new OpenAIAgentsProvider(),
});

What's happening:

dotenv.config() loads your .env file so COMPOSIO_API_KEY and USER_ID are available as environment variables.
Creating a Composio instance using the API Key and OpenAIAgentsProvider class.

Create a Tool Router session

// Create Tool Router session for Square
const session = await composio.create(userId as string, {
  toolkits: ['square'],
});
const mcpUrl = session.mcp.url;

What is happening:

You give the Tool Router the user id and the toolkits you want available. Here, it is only square.
The router checks the user's Square connection and prepares the MCP endpoint.
The returned session.mcp.url is the MCP URL that your agent will use to access Square.
This approach keeps things lightweight and lets the agent request Square tools only when needed during the conversation.

Configure the agent

// Configure agent with MCP tool
const agent = new Agent({
  name: 'Assistant',
  model: 'gpt-5',
  instructions:
    'You are a helpful assistant that can access Square. Help users perform Square operations through natural language.',
  tools: [
    hostedMcpTool({
      serverLabel: 'tool_router',
      serverUrl: mcpUrl,
      headers: { 'x-api-key': composioApiKey },
      requireApproval: 'never',
    }),
  ],
});

What's happening:

We're creating an Agent instance with a name, model (gpt-5), and clear instructions about its purpose.
The agent's instructions tell it that it can access Square and help with queries, inserts, updates, authentication, and fetching database information.
The tools array includes a hostedMcpTool that connects to the MCP server URL we created earlier.
The headers object includes the Composio API key for secure authentication with the MCP server.
requireApproval: 'never' means the agent can execute Square operations without asking for permission each time, making interactions smoother.

Start chat loop and handle conversation

// Keep conversation state across turns
const conversationSession = new OpenAIConversationsSession();

// Simple CLI
const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
  prompt: 'You: ',
});

console.log('\nComposio Tool Router session created.');
console.log('\nChat started. Type your requests below.');
console.log("Commands: 'exit', 'quit', or 'q' to end\n");

try {
  const first = await run(agent, 'What can you help me with?', { session: conversationSession });
  console.log(`Assistant: ${first.finalOutput}\n`);
} catch (e) {
  console.error('Error:', e instanceof Error ? e.message : e, '\n');
}

rl.prompt();

rl.on('line', async (userInput) => {
  const text = userInput.trim();

  if (['exit', 'quit', 'q'].includes(text.toLowerCase())) {
    console.log('Goodbye!');
    rl.close();
    process.exit(0);
  }

  if (!text) {
    rl.prompt();
    return;
  }

  try {
    const result = await run(agent, text, { session: conversationSession });
    console.log(`\nAssistant: ${result.finalOutput}\n`);
  } catch (e) {
    console.error('Error:', e instanceof Error ? e.message : e, '\n');
  }

  rl.prompt();
});

rl.on('close', () => {
  console.log('\n👋 Session ended.');
  process.exit(0);
});

What's happening:

The program prints a session URL that you visit to authorize Square.
After authorization, the chat begins.
Each message you type is processed by the agent using run().
The responses are printed to the console.
Typing exit, quit, or q cleanly ends the chat.

Complete Code

Here's the complete code to get you started with Square and OpenAI Agents SDK:

import 'dotenv/config';
import { Composio } from '@composio/core';
import { OpenAIAgentsProvider } from '@composio/openai-agents';
import { Agent, hostedMcpTool, run, OpenAIConversationsSession } from '@openai/agents';
import * as readline from 'readline';

const composioApiKey = process.env.COMPOSIO_API_KEY;
const userId = process.env.USER_ID;

if (!composioApiKey) {
  throw new Error('COMPOSIO_API_KEY is not set. Create a .env file with COMPOSIO_API_KEY=your_key');
}
if (!userId) {
  throw new Error('USER_ID is not set');
}

// Initialize Composio
const composio = new Composio({
  apiKey: composioApiKey,
  provider: new OpenAIAgentsProvider(),
});

async function main() {
  // Create Tool Router session
  const session = await composio.create(userId as string, {
    toolkits: ['square'],
  });
  const mcpUrl = session.mcp.url;

  // Configure agent with MCP tool
  const agent = new Agent({
    name: 'Assistant',
    model: 'gpt-5',
    instructions:
      'You are a helpful assistant that can access Square. Help users perform Square operations through natural language.',
    tools: [
      hostedMcpTool({
        serverLabel: 'tool_router',
        serverUrl: mcpUrl,
        headers: { 'x-api-key': composioApiKey },
        requireApproval: 'never',
      }),
    ],
  });

  // Keep conversation state across turns
  const conversationSession = new OpenAIConversationsSession();

  // Simple CLI
  const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout,
    prompt: 'You: ',
  });

  console.log('\nComposio Tool Router session created.');
  console.log('\nChat started. Type your requests below.');
  console.log("Commands: 'exit', 'quit', or 'q' to end\n");

  try {
    const first = await run(agent, 'What can you help me with?', { session: conversationSession });
    console.log(`Assistant: ${first.finalOutput}\n`);
  } catch (e) {
    console.error('Error:', e instanceof Error ? e.message : e, '\n');
  }

  rl.prompt();

  rl.on('line', async (userInput) => {
    const text = userInput.trim();

    if (['exit', 'quit', 'q'].includes(text.toLowerCase())) {
      console.log('Goodbye!');
      rl.close();
      process.exit(0);
    }

    if (!text) {
      rl.prompt();
      return;
    }

    try {
      const result = await run(agent, text, { session: conversationSession });
      console.log(`\nAssistant: ${result.finalOutput}\n`);
    } catch (e) {
      console.error('Error:', e instanceof Error ? e.message : e, '\n');
    }

    rl.prompt();
  });

  rl.on('close', () => {
    console.log('\nSession ended.');
    process.exit(0);
  });
}

main().catch((err) => {
  console.error('Fatal error:', err);
  process.exit(1);
});

Conclusion

This was a starter code for integrating Square MCP with OpenAI Agents SDK to build a functional AI agent that can interact with Square.

Key features:

Hosted MCP tool integration through Composio's Tool Router
SQLite session persistence for conversation history
Simple async chat loop for interactive testing

You can extend this by adding more toolkits, implementing custom business logic, or building a web interface around the agent.

TOOLS

Supported Tools

Every Square action and event your agent gets out of the box.

Accept Dispute

Accept a dispute and acknowledge liability, returning funds to the cardholder.

Add Group to Customer

Tool to add a customer to a customer group.

Calculate Order

Tool to preview order pricing without creating an order.

Cancel Invoice

Cancels a Square invoice, preventing further payments from being collected.

Cancel Payment

Cancels (voids) a payment that is in APPROVED status.

Create Bulk Customers

Tool to create multiple customer profiles in a single request.

Create Card

Tool to create a card on file.

Create Customer

Tool to create a new customer profile in Square.

Create Customer Custom Attribute Definition

Tool to create a customer-related custom attribute definition.

Create Customer Group

Tool to create a new customer group for a business.

Create Dispute Evidence File

Tool to upload a file as dispute evidence.

Create Dispute Evidence Text

Upload text evidence for a dispute challenge.

Create Invoice Attachment

Upload and attach a file to a Square invoice.

Create Location

Tool to create a new business location in a Square account.

Create Location Custom Attribute Definition

Tool to create a location-related custom attribute definition.

Delete Customer

Tool to delete a Square customer profile.

Delete Customer Custom Attribute

Tool to delete a custom attribute from a customer profile.

Delete Customer Custom Attribute Definition

Tool to delete a customer-related custom attribute definition.

Delete Customer Group

Tool to delete a customer group by its ID.

Bulk Delete Customers

Tool to bulk delete customer profiles from Square.

Delete Dispute Evidence

Removes a specific piece of evidence from a dispute.

Delete Invoice

Tool to delete a Square invoice (only DRAFT invoices can be deleted).

Delete Invoice Attachment

Tool to delete an attachment from a Square invoice.

Delete Location Custom Attribute

Tool to delete a custom attribute from a location.

Delete Location Custom Attribute Definition

Tool 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 Attribute

Tool to delete a custom attribute from a merchant profile.

Delete Merchant Custom Attribute Definition

Tool 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 Subscription

Permanently deletes a webhook subscription by its ID.

Get Business Booking Profile

Tool to retrieve the business booking profile for a Square merchant via GraphQL.

Get Current Merchant

Tool to retrieve merchant information associated with the access token using Square's GraphQL API.

Get Customer Custom Attribute

Retrieves a custom attribute from a customer profile in Square.

Get Customer Custom Attribute Definition

Tool to retrieve a customer-related custom attribute definition from Square.

Get Customers via GraphQL

Tool to retrieve customer profiles from Square Customer Directory using GraphQL API.

Get Dispute Evidence

Retrieves detailed information about a specific piece of evidence that was uploaded for a dispute.

Get Invoice

Retrieves detailed information about a specific Square invoice by its ID.

Get Merchant

Tool to retrieve detailed information about a specific Square merchant by ID.

Get Online Checkout Location Settings

Tool to retrieve location-level settings for Square online checkout.

List Channels

Tool to list requested channels from Square.

List Customer Custom Attribute Definitions

Tool 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 Attributes

Tool to list custom attributes for a customer profile.

List Customer Groups

Tool to retrieve the list of customer groups of a business.

List Customers

Tool to retrieve customer profiles associated with a Square account.

List Customer Segments

Tool to retrieve the list of customer segments of a business.

List Dispute Evidence

Tool to list evidence items associated with a given dispute.

List Invoices

Tool to list invoices for a Square location.

List Location Custom Attribute Definitions

Tool to list location-related custom attribute definitions from Square.

List Locations

Tool to retrieve all business locations from a Square account.

List Locations Custom Attributes

Tool to list custom attributes for a specific location in Square.

List Merchant Custom Attribute Definitions

Tool to list merchant-related custom attribute definitions from Square.

List Merchants

Tool to retrieve merchant account information associated with the access token.

List Merchants Custom Attributes

Tool to list custom attributes for a specific merchant in Square.

List Payments

Tool to list payments by location and time range to enable reconciliation and net sales reporting from Square POS.

List Webhook Event Types

Tool to list available webhook event types.

List Webhook Subscriptions

List all webhook subscriptions owned by your application.

Remove Group From Customer

Removes a customer from a customer group.

Retrieve Bulk Customers

Tool to retrieve multiple customer profiles in a single request.

Retrieve Channel

Retrieve a Square channel by its ID.

Bulk Retrieve Channels

Tool to bulk retrieve multiple Square channels by their IDs in a single request.

Retrieve Customer

Tool to retrieve detailed information about a specific Square customer by ID.

Retrieve Customer Group

Tool to retrieve a specific Square customer group by ID.

Retrieve Customer Segment

Tool to retrieve a specific customer segment by its ID.

Retrieve Dispute

Tool to retrieve a Square dispute by ID.

Retrieve Location

Tool to retrieve detailed information about a specific Square location by ID.

Retrieve Location Custom Attribute

Retrieves a custom attribute associated with a location in Square.

Retrieve Location Custom Attribute Definition

Tool to retrieve a location-related custom attribute definition.

Retrieve Merchant Custom Attribute

Retrieves a custom attribute associated with a merchant in Square.

Retrieve Merchant Custom Attribute Definition

Tool to retrieve a merchant-related custom attribute definition from Square.

Retrieve Merchants

Tool to retrieve merchant information including status, main location details, and capabilities using Square's GraphQL API.

Retrieve Order

Retrieves detailed information about a specific Square order by its ID.

Retrieve Payment Link

Retrieves a Square-hosted payment link by ID.

Retrieve Token Status

Tool to retrieve information about an OAuth access token or personal access token.

Retrieve Webhook Subscription

Retrieve a Square webhook subscription by its ID.

Search Customers

Tool to search customer profiles in Square Customer Directory.

Search Orders

Tool to search orders across one or more Square locations with filters.

Submit Dispute Evidence

Submits evidence for a dispute to the cardholder's bank.

Test Webhook Subscription

Tests a webhook subscription by sending a test event to the configured notification URL.

Update Customer

Tool to update an existing Square customer profile.

Update Customer Custom Attribute Definition

Tool to update a customer-related custom attribute definition in Square.

Update Customer Group

Tool to update a customer group's information by its ID.

Bulk Update Customers

Tool to update multiple customer profiles in a single batch operation.

Update Location

Tool to update an existing business location in a Square account.

Update Location Custom Attribute Definition

Tool to update a location-related custom attribute definition in Square.

Update Merchant Custom Attribute Definition

Tool to update a merchant-related custom attribute definition in Square.

Update Online Checkout Location Settings

Tool to update location-level settings for Square online checkout.

Update Order

Updates an existing Square order by adding, modifying, or removing fields.

Update Webhook Subscription

Tool to update a Square webhook subscription.

Update Webhook Subscription Signature Key

Tool to rotate the signature key for a webhook subscription.

Upsert Customer Custom Attribute

Tool to create or update a custom attribute for a customer profile.

Batch Upsert Customer Custom Attributes

Tool to create or update custom attributes for multiple customers in a single batch request.

Upsert Location Custom Attribute

Tool to create or update a custom attribute for a location.

Batch Upsert Locations Custom Attributes

Tool to create or update custom attributes for multiple locations in a single batch request.

Upsert Merchant Custom Attribute

Tool to create or update a custom attribute for a merchant profile.

Batch Upsert Merchants Custom Attributes

Tool to create or update custom attributes for multiple merchants in a single batch request.

FRAMEWORKS

How to build Square MCP Agent with another framework

Claude Agent SDK

Use Square MCP with Claude Agent SDK

Claude Code

Use Square MCP with Claude Code

Claude Cowork

Use Square MCP with Claude Cowork

Codex

Use Square MCP with Codex

OpenClaw

Use Square MCP with OpenClaw

Hermes

Use Square MCP with Hermes

CLI

Use Square MCP with CLI

Google ADK

Use Square MCP with Google ADK

LangChain

Use Square MCP with LangChain

Vercel AI SDK

Use Square MCP with Vercel AI SDK

Mastra AI

Use Square MCP with Mastra AI

LlamaIndex

Use Square MCP with LlamaIndex

CrewAI

Use Square MCP with CrewAI

MORE TOOLKITS

Explore Other Toolkits

Toolkit marketplace

Addresszen

Api Key

Addresszen is a real-time address autocomplete and verification service. It helps capture accurate, deliverable addresses with instant suggestions and validation.

Asin data api

Api Key

Asin data api gives you detailed, real-time product data from Amazon, including price, rank, and reviews. Perfect for e-commerce pros and data-driven marketers who need instant marketplace insights.

Baselinker

Api Key

BaseLinker is an all-in-one e-commerce management platform connecting stores, marketplaces, carriers, and more. It streamlines order processing, inventory control, and automates your sales operations.

Bestbuy

Api Key

Best Buy is a leading retailer offering APIs for product, store, and recommendation data. Instantly access up-to-date retail insights for smarter shopping and decision-making.

FAQ

Frequently asked questions

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.

Yes, you can. OpenAI Agents SDK 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.

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.

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.

Start with Square.It takes 30 seconds.

Managed auth, hosted MCP servers, and every Square tool your agent needs.Free to start.

Start building

Customer stories

Teams ship real agents on Composio

GET STARTED FOR FREE BOOK A DEMO

Karan skipped his own birthday party to fix our critical issue. It was 10pm and he diverted his Waymo to help us instead. This really sets the bar — it shows the commitment you need when users rely on your software.

Harsha Gaddipati

Co-founder, Slashy

A lot of students tell us that the moment their connected tools start talking to each other inside Opennote feels almost magical. The agent just knows them, and it's immensely helped keep new users on the platform.

Abhi Arya

Co-founder, Opennote

We chose Composio over Pipedream because it delivered depth where it mattered — niche tools and tricky edge cases other platforms simply ignored. That gave us confidence to scale without compromising.

Nirman Dave

CEO, Zams

As a solo builder, shipping fast is life or death. The only way I can outcompete incumbents is by outmanoeuvring them. Getting bogged down managing agent auth would have been a death sentence.

Ryan Yu

Founder, Extra Thursday

Before Composio, adding tool integrations was slow and resource-intensive. Each one could take weeks of engineering time, and maintaining them meant constantly keeping up with API changes.

Tomisin Jenrola

Founder & CEO, SwarmZero

With hands-on help from their founder, we integrated Gmail and Google Drive in just 30 minutes. This level of personal support and commitment is exactly what startups should strive for.

Jerome Leclanche

Co-Founder, Ingram Technologies

How to integrate Square MCP with OpenAI Agents SDK

Connect Square without auth hassles

Introduction

Also integrate Square with

TL;DR

What is OpenAI Agents SDK?

What is the Square MCP server, and what's possible with it?

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

What is Composio SDK?

How the Composio SDK works

Step-by-step Guide

Prerequisites

Getting API Keys for OpenAI and Composio

Install dependencies

Set up environment variables

Import dependencies

Set up the Composio instance

Create a Tool Router session

Configure the agent

Start chat loop and handle conversation

Complete Code

Conclusion

Supported Tools

How to build Square MCP Agent with another framework

Claude Agent SDK

Claude Code

Claude Cowork

Codex

OpenClaw

Hermes

CLI

Google ADK

LangChain

Vercel AI SDK

Mastra AI

LlamaIndex

CrewAI

Explore Other Toolkits

Addresszen

Asin data api

Baselinker

Bestbuy

Frequently asked questions

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

Can I use Tool Router MCP with OpenAI Agents SDK?+

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

How safe is my data with Composio Tool Router?+

Start with Square.It takes 30 seconds.

Teams ship real agents on Composio