ChatGPTby OpenAI

Connect Marnie to ChatGPT

Add Marnie to ChatGPT as a custom app in Developer mode, then ask what you spent on food, what's due this week or how close you are to a savings goal. ChatGPT answers with Marnie's own cards.

Needs Marnie ProNeeds a ChatGPT plan with Developer mode.

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Pro

Paste this into your assistant as the server URL. It's also in the app under Profile → AI agents.

https://bimzexydbsqfvqthtrgl.supabase.co/functions/v1/mcp

Connecting an assistant needs Marnie Pro. You choose whether it can suggest transactions, and you can disconnect it any time in Profile → AI agents.

Watch the setup

Every step in ChatGPT, from copying the link to tapping Allow.

Set up ChatGPT in 3 steps

  1. Settings → Apps → Developer mode

    In ChatGPT on the web, open Settings → Apps → Advanced settings and turn on Developer mode.

  2. Create an app, paste the link, choose OAuth

    Choose Create app, name it Marnie, paste the link below as the MCP server URL and pick OAuth for authentication.

  3. Sign in to Marnie and tap Allow

    A Marnie page opens. Sign in with the account you use in the app, choose whether the assistant may suggest transactions, then tap Allow access.

Plan note: Needs a ChatGPT plan with Developer mode.

Before you start, in Marnie

Do this once. It covers every assistant you connect.

  1. Marnie Pro

    Connecting an assistant is part of Marnie Pro. Siri, widgets and capture stay free.

  2. Turn on sharing

    In Marnie, open Profile → AI agents and switch on Share with AI agents. Marnie then keeps a short summary for your assistants, refreshed when you use the app.

  3. Copy the link

    It's the same link for everyone, shown on this page and in Profile → AI agents. Signing in is what ties it to your account.

Step by step in ChatGPT

Turn on Developer mode

  1. Go to chatgpt.com in a browser and open Settings → Apps. Depending on your version, this area is called Apps, Connectors or Plugins.
  2. Open Advanced settings and switch on Developer mode. In a Business or Enterprise workspace, an admin may need to allow it first.

Create the Marnie app

  1. Back in Settings → Apps, choose Create app.
  2. Name it Marnie, paste the Marnie link as the MCP server URL and choose OAuth as the authentication method.
  3. Confirm that you trust the app, then choose Create. A Marnie sign-in page opens.
  4. Sign in, decide whether ChatGPT may suggest transactions, and tap Allow access. You're sent back to ChatGPT.

Use it in a chat

  1. Start a new chat, open the + menu under the message box and pick Marnie (it may sit under More or Developer mode).
  2. Ask your question. ChatGPT shows which Marnie tool it's calling and asks you to confirm anything that adds a draft.

On your phone

  1. Developer mode apps are created on the web, not in the ChatGPT phone app. Set Marnie up at chatgpt.com first.
  2. Whether the app then shows in ChatGPT on your phone depends on your plan and OpenAI's current rollout. If it doesn't, use chatgpt.com in your phone's browser.

What you can ask ChatGPT

Answers come back as Marnie cards: the spending, the bills or the goal, laid out the way the app shows them.

ChatGPT sees only the summary Marnie shares. Balances, net worth, notes, receipts, card and account numbers and your location never leave your phone.

  • “How much did I spend this month?”Your total and the top categories, with last month alongside. Also works for today, this week, last month and this year.
  • “What did I spend on coffee last month?”The matching payments from the last 90 days, filtered by category, merchant or type, with the total.
  • “Which bills are coming up?”The next bills and payday Marnie knows about, with dates and amounts.
  • “Am I safe to spend this weekend?”What's left in your budget for the period and how much that is per day.
  • “How close am I to my savings goals?”Each goal's progress, saved amount and target.
  • “Add a $12 lunch at Subway”A draft in Capture Review, if you allowed suggestions when you connected. It's saved once you approve it.

If something goes wrong

The usual fixes, starting with the ones specific to ChatGPT.

There's no Developer mode or Create app
Developer mode is only on some ChatGPT plans, and only on the web. In a Business or Enterprise workspace, ask an admin to allow custom apps.
ChatGPT says it can't reach the server
Check you pasted the whole link, with nothing after /mcp, and that OAuth is selected. Then delete the app and create it again.
The sign-in page says “This request has expired”
Connection requests last 10 minutes and work once. Go back to the assistant and start connecting again.
It says connecting is part of Marnie Pro
The account you signed in with doesn't have Marnie Pro. Upgrade in the app, or choose Not you? and sign in with the account that has it.
I sign in to Marnie with Apple or Google
Use the email option on the Marnie sign-in page: enter the email your Marnie account uses and type the code we send. Using Hide My Email? The code goes to that relay address and is forwarded to you.
The assistant says there's nothing to show
Check Share with AI agents is on in Profile → AI agents, then open Marnie once so it can send its first summary.
The numbers are a day or two old
Marnie refreshes the summary when you use the app. Open Marnie, then ask again.
A purchase I asked it to add isn't in Marnie
Suggestions arrive as drafts in Capture Review the next time you open Marnie. If the assistant says it can't add, reconnect and tick Suggest transactions on the Marnie page.

ChatGPT and Marnie: questions

Which ChatGPT plans can add Marnie?

Plans that include Developer mode on the web. OpenAI changes which plans get it, so check Settings → Apps → Advanced settings. In Business and Enterprise workspaces an admin may need to turn custom apps on.

Is it called Apps, Connectors or Plugins?

OpenAI has used all three names for the same area. Look for the option to create an app or add a custom MCP server, paste the Marnie link and choose OAuth.

Can ChatGPT change my budget or move money?

No. ChatGPT can read the summary Marnie shares and, if you allow it, suggest transactions. Those wait in Capture Review until you approve them in Marnie. It can't edit or delete anything, and Marnie never moves money.

How do I disconnect ChatGPT?

In Marnie, open Profile → AI agents and remove ChatGPT. Its next request is refused. You can also delete the app in ChatGPT's settings.

Other assistants

Ask ChatGPT how your money's doing.

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Marnie is free to start on iPhone and Android. Connecting AI agents is part of Marnie Pro.

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