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    ChatGPT

    In ChatGPT you can ask about your own transactions and get a closed answer, a probability and an abstain flag back, from seven question tools: restricted merchant, spend type, receipt match, refund pairing, return window, support queue and your own closed question. The plugin offers no health tools.

    Not open yet. Opens with early access.

    On this page

    Before you start

    • Access. Custom MCP servers in ChatGPT are documented for ChatGPT Business and for Enterprise and Edu, on the web. On Business only admins and owners can turn on developer mode and add a server. On Enterprise and Edu an admin can hand that right to members. A workspace setting called Lockdown can hide the option.
    • An Understanding account. Sign up if you have none. New accounts get $5 of credit.
    • No API key. ChatGPT cannot send a pasted key. It signs you in instead, so there is nothing to copy.

    Set it up

    1. In ChatGPT on the web, open Plugins (chatgpt.com/plugins), press +, and choose Add custom MCP server.
    2. Name it Understanding. For the server URL enter https://api.theunderstanding.company/mcp/chatgpt.
    3. For Authentication choose OAuth. If ChatGPT asks how it should register itself, choose either. The server supports both Client ID Metadata Documents and dynamic client registration. Try the metadata document first, then dynamic registration.
    4. Accept the risk warning and choose Create as a plugin.
    5. Open the plugin's details page. You should see seven question tools and get_usage. Install the plugin.
    6. Start a new chat, type @ and pick Understanding.
    7. The first time a tool runs, ChatGPT sends you to our sign-in page. Sign in with your Understanding account. The approval screen names the app by its address (chatgpt.com) and asks you to Allow.

    The approval gives ChatGPT one permission, understand:read. It lets the app ask the questions and read your usage, and nothing else. After we change a tool, open the plugin's details page, choose Refresh, and start a new conversation.

    What we tuned for this service

    The /mcp/chatgpt address is the standard server with these changes. They change wording and result shape only, never behavior or billing.

    • Descriptions follow "Use this when... Do not use for...". OpenAI's plugin guidance asks for descriptions in that form.
    • The first 512 characters of the server's instructions stand on their own. They say what the server does, that every answer has a probability and an abstain flag, and that card and account numbers must not be sent.
    • Each result is one line led by the abstain flag, then the answer, the probability and the reasons, plus structured content that matches a declared output schema. Results carry no request ids or timestamps.
    • Every tool is marked read-only. ChatGPT treats a tool without that mark as an action and asks before running it. Ours are lookups: they do not change your bank, your transactions or your account settings. Each call does write a usage record (counts and cost, no request content), as the data and privacy page says.
    • Each tool names OAuth as its security scheme.
    • No pricing, trial or comparison wording appears in the descriptions. OpenAI's plugin rules do not allow it there. Plans are on our site.

    Check that it works

    Paste this into a new chat after typing @Understanding:

    Text
    My statement has a charge from DRAFTKINGS with merchant category code 7995. Is that a restricted merchant?

    ChatGPT should call Check restricted merchant (check_restricted_merchant). The tool result is one line:

    Text
    Abstain: false. Answer: yes. Probability: 0.97. Reasons: mcc_7995, rule_gambling_category, kind_sportsbook.

    ChatGPT then answers in its own words and should quote the probability. Now a case that abstains:

    Text
    My statement has a charge from LUCKY COINS LLC with merchant category code 5816. Is that a restricted merchant?
    Text
    Abstain: true, do not rely on this answer. Leaning: yes. Probability: 0.62. Reasons: mcc_5816, kind_sweepstakes_casino.

    ChatGPT should say it is unsure and leave the call to you. The numbers show the format. They are not measured results; yours come from the model.

    If it doesn't connect

    • There is no Add custom MCP server option. Check the plan and your role above. In a Business workspace an admin must turn on developer mode first. Lockdown can also hide it.
    • The sign-in page does not open, or fails after you approve. ChatGPT sends the sign-in back to an address on chatgpt.com. The approval screen shows where it will send you; cancel if it shows another host. Do not paste a key into ChatGPT to get around it.
    • ChatGPT says the client is invalid, or asks you to sign in again and again. If ChatGPT registered itself and you then deleted and re-added the plugin, the old registration is gone. Remove the plugin, add it again, and sign in once more.
    • The tools are missing or out of date. Open the plugin's details page, choose Refresh, and start a new conversation.
    • It asks to confirm every call. The tools are marked read-only, so this should be rare. ChatGPT lets you remember an approval inside one conversation.
    • It worked, then stopped. An access token lasts an hour and ChatGPT renews it with a refresh token. If you revoked the app under Connected apps in the console, or a refresh token was used twice, the connection is revoked. Connect again.
    • A tool returns out_of_credit. The account has no credit left. See Pricing.