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How to integrate Square using MCP

Payments, orders and inventory. This guide creates an MCP server from Arthur's Square template — tools preconfigured against https://connect.squareup.com/v2 — and finishes by sharing the server's MCP swagger documentation.

Steps

  1. Open the Secrets vault and create a secret named SQUARE_API_KEY holding your access token. Create an application at developer.squareup.com and use the Production or Sandbox Access Token.

    Open the Secrets vault to store the Square credential before using the template

    Start the New secret wizard

    Name the secret SQUAREAPIKEY — servers reference it by this name

  2. Go to the REST API Templates gallery and search for Square.

    Record what the credential is for so it stays recognizable

    Continue to the protected value step

  3. Click Use template on the Square card to open the server-creation dialog.

    Enter the credential value — a demo value here; use your real key when adopting the integration

    Review the generated secret reference syntax

  4. Review the server name and select SQUARE_API_KEY in the credential field — the dialog only accepts vault secrets, and it lists every tool that will be created.

    Store the SQUAREAPIKEY secret in the vault

    Open the REST API template gallery

    Search the gallery for the Square integration

  5. Click Create server. Arthur creates the server, applies the authentication, and generates all the tools.

    Open the Square template with its preconfigured tools

    Name the server after the integration it provides

    Pick the SQUAREAPIKEY secret from the vault suggestions

    Select the stored credential

    Create the Square server with its preconfigured tools

  6. Open the server's Tools tab to review the generated tools.

    Review the tools generated from the Square template

  7. Open the server's Connect section and click Share the MCP swagger documentation — Arthur generates the public documentation link and QR code for this server.

    Open the server's Connect section, where the MCP endpoint and its documentation live

    Open the MCP swagger documentation share panel

    Show the generated swagger documentation link and QR code for this server

Confirm it worked

The server appears with 4 preconfigured tool(s): list_payments, list_customers, search_catalog, list_locations. The Connect section offers the MCP swagger documentation — a shareable page with setup instructions for any AI client.

Good to know

  • Access Square payments, customers, catalog items, and locations via the Square REST API. Use the sandbox environment for testing.
  • This integration requires a credential (bearer). Get one at https://developer.squareup.com/apps.
  • Official API documentation: https://developer.squareup.com/reference/square
  • Editing a tool later never changes the template — templates are starting points, and the server is fully yours after creation.

Related

Tutorial video