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ChatGPT can browse the Nevermined Catalog and pay for services as it works, without you handing over an API key. You add one MCP app, approve a single spending cap, and ChatGPT does the rest. This is the per-host walkthrough; for the concept and the other assistants, see Using the Catalog from your web assistant.
This covers the manual connection — adding the Catalog as a custom MCP app in Developer mode, which works today. A one-click listing in ChatGPT’s connector directory is still in progress — see From the ChatGPT directory.

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See it in action

Connect the Catalog from ChatGPT.

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Before you connect

1

A Nevermined account

Free, at nevermined.app. You never share an API key with ChatGPT — the consent cap is the credential.
2

A paid ChatGPT plan

Developer mode, where custom MCP apps live, needs a paid plan (Plus or above).
3

A funded wallet

A paid call draws on a spending cap you approve during connect — a commerce grant: a capped, revocable budget funded from your own wallet, not a key. Fund that wallet first with the asset the service settles in — see Fund your wallet. You approve the cap itself in Approve the spending cap.
Start on sandbox, where you use testnet funds and nothing costs real money, before you point ChatGPT at live.

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Add the Catalog to ChatGPT

1

Turn on Developer mode

Settings → Security and login → Developer mode. Plugins then appears in the sidebar.
2

Create an MCP app

Plugins → ＋ → Create app → Create MCP app. (The ＋ menu’s Create plugin builds a plugin from scratch — not what you want.)
3

Fill in the dialog

  • Name — read the warning below first; you only get one shot at it.
  • Connection — leave it on Server URL and paste the URL for your environment:
  • Authentication — OAuth, with the client ID and secret empty. ChatGPT discovers the OAuth settings from the server itself; leave Advanced OAuth settings closed.
  • Tick I understand and want to continue under the “Custom MCP servers introduce risk” notice.
Choose the name carefully — a ChatGPT plugin cannot be deleted or renamed. Names are unique per account, so a name you have used is taken for good, and uninstalling does not free it.

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Approve the spending cap

ChatGPT runs Nevermined’s consent at creation — immediately, before any tool call. It is the one place a human is required.
1

Trigger the consent

When you create the MCP app, ChatGPT shows Add Nevermined … to ChatGPT? and opens the consent page.
2

Check who and where

The page shows the Sandbox / Live badge and that chatgpt.com is asking. On live, the cap is real money.
3

Set the cap and validity

Set the spending cap (USDC or EURC) and how long the grant is valid for, then Grant access. The plugin shows as connected.
That approval is a commerce grant: it spends only from the budget you just approved, only through the Router, and you can revoke it any time. Nevermined’s routing fee comes out of the same cap, and the grant can also read your payment history and wallet balance — the cap bounds what it can spend, not what it can see.

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Make your first paid call

Ask for something only live data can answer, and name the connector so ChatGPT reaches for it rather than answering from memory.
1

Browse for free

In a new chat the plugin is available automatically. Ask “list the Nevermined catalog categories” — a free call, no sign-in.
2

Ask it to buy

“Buy the service with slug <slug> through the Nevermined connector and show me the response.” Each paid call first asks Allow ChatGPT to use Nevermined …? — Allow (once, or always), and it returns the merchant’s response.
If ChatGPT answers without paying, it answered from its own knowledge — name the connector and ask for live data. Confirm the connection by asking for the Catalog categories, which is a free call that either works or doesn’t. More on phrasing: Catalog MCP tips.

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Disconnect

  • Revoke the budget (Nevermined side). Open Connections and disconnect ChatGPT. The credential stops working on its next call; discovery still works. On the next paid call ChatGPT shows a Reconnect Nevermined card (its wording says the connection “expired” even when you revoked it).
  • Remove the connector (ChatGPT side). Uninstall the plugin from Plugins. Note the plugin cannot be deleted or renamed, and uninstalling does not free its name.
To spend again — after you disconnect, or after a cap is used up — re-run the connect step and approve a new cap. A budget is never widened or extended in place.

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From the ChatGPT directory

A one-click listing in ChatGPT’s app directory — so you can add the Catalog without Developer mode — is coming. Until then, use the manual path above.

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Next

Using the Catalog from your web assistant

The concept and the other assistants.

Catalog MCP — full reference

Every click path, the consent details, and every refusal code.