Add Arqa to ChatGPT, step by step

This short guide adds Arqa to ChatGPT as a connector (ChatGPT now calls connectors apps). Once connected, ChatGPT can read your Arqa projects and saved plans, review plans and building ideas, and generate new floor plans. Use through ChatGPT spends the credits of your Arqa account, as the website does. The tools and their arguments are described in the MCP guide.

ChatGPT's menus change over time and differ between plans. If a name below does not match your screen, look for the closest equivalent.

Before you start

  • A ChatGPT account whose plan allows apps. In a business or education workspace, an admin may have to allow custom apps first.
  • An Arqa account with its own password: request access on the website waitlist if you have none, and set your password there if you still have the temporary one from your approval email. Connecting creates no account.
  • Only for a custom app (option B): the Arqa OAuth client ID and client secret, which you get from Arqa support. They are not your Arqa password. Never paste them into a chat message.

Option A: add Arqa from the app directory

If Arqa is listed in ChatGPT, this is the quickest way.

  1. In ChatGPT, open Settings, then Apps (Apps & Connectors on some plans).
  2. Search for Arqa, open it and select Connect.
  3. Sign in as described under "Sign in and authorize" below.

Option B: add Arqa as a custom app

Use this when Arqa is not listed for your account, or to test a connection.

  1. In ChatGPT, open Settings, then Apps, then Advanced settings, and turn on Developer mode.
  2. Back in Settings, then Apps, select Create app.
  3. Enter a name such as Arqa, a short description such as "Design and review house floor plans", and the MCP server URL https://app.arqa.ing/mcp.
  4. Under Authentication, choose OAuth, open the advanced OAuth settings and enter the values listed after these steps. ChatGPT may fill some of them from Arqa's discovery metadata; check that every value matches.
  5. Check the Callback URL that ChatGPT shows. Arqa accepts https://chatgpt.com/connector_platform_oauth_redirect. If ChatGPT shows a different one, send it to Arqa support before continuing; an unregistered callback fails with "Unrecognized OAuth client or redirect URI".
  6. Accept the warning about custom apps and select Create. ChatGPT opens the Arqa sign-in page.

Advanced OAuth settings for step 4:

Client registration method:  User-Defined OAuth Client
OAuth Client ID:             the client ID Arqa gave you
OAuth Client Secret:         the client secret Arqa gave you
Token endpoint auth method:  client_secret_post
Auth URL:                    https://app.arqa.ing/connect
Token URL:                   https://app.arqa.ing/mcp/oauth/token
Registration URL:            leave empty
Authorization server base:   https://app.arqa.ing
Resource:                    https://app.arqa.ing/mcp
Scopes:                      projects:read plans:generate
OIDC:                        off

Sign in and authorize

  1. On the Arqa /connect page, review the permissions ChatGPT asks for: reading your projects and plans, and generating plans.
  2. Enter the username and password of your Arqa account, the same ones you use on the website, and select Sign in and authorize.
  3. When the page confirms the connection, return to ChatGPT. Arqa now appears in your apps as connected.

Connecting never signs you in to the Arqa website, and a direct visit to /connect grants nothing: always start from ChatGPT.

Use Arqa in a chat

  1. Start a new chat. Open the + menu in the message box and select Arqa (under More, or Developer mode for a custom app).
  2. Ask for what you need, for example: "With Arqa, design a one-floor house of 1,200 sq ft with 2 bedrooms and 1 bathroom in Bogota, Colombia."
  3. ChatGPT asks for missing details and asks you to confirm the design before generating. Confirm each Arqa action ChatGPT proposes.
  4. Open the saved plan in the Arqa web app to edit it, add electrical or plumbing layouts, drawing sheets or 3D. Through ChatGPT, existing plans are read-only.

If something fails

  • "Unrecognized OAuth client or redirect URI": the client ID, client secret or callback URL does not match what Arqa registered. Check the values above or ask support.
  • "Reconnect your Arqa account": the connection expired or was revoked. A connection lasts at most 30 days. Open Settings, then Apps, then Arqa, and connect again.
  • "Wrong username or password, or this account cannot connect yet": check your website credentials; an account that still has its temporary password sets its own on the website first. A disabled account: write to Arqa support.
  • No Developer mode or Create app option: your plan or workspace does not allow custom apps. Use option A, or ask your workspace admin.
  • Arqa tools are missing: the connection was authorized with fewer permissions. Disconnect and connect again, accepting both permissions.

Disconnect

Open Settings, then Apps, then Arqa, and disconnect or delete it. ChatGPT stops using the connection immediately. To also invalidate tokens already issued, ask Arqa support.

Arqa produces concept floor plans, not permit sets or construction documents. Have a qualified professional review them before relying on them.