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Hermes Agent can browse the Nevermined Catalog and pay for services as it works, without you handing over an API key. You add one server, approve a single spending cap, and Hermes Agent does the rest. This is the per-host walkthrough; for the concept and the other assistants, see Using the Catalog from your web assistant.

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Before you connect

1

A Nevermined account

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

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 Hermes Agent at live.

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Add the Catalog to Hermes Agent

1

Add the server

Add the Catalog as an OAuth-protected HTTP server (no API key or client secret — OAuth with PKCE):
2

Sign in

Run hermes mcp login nevermined from a fresh terminal. Hermes opens Nevermined’s consent page (or prints a URL to paste when it runs headless). Check the tools loaded with hermes mcp test nevermined.

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Approve the spending cap

Hermes Agent opens Nevermined’s consent page when you run hermes mcp login. It is the one place a human is required.
1

Check who and where

The page shows the Sandbox / Live badge and who is asking. On live, the cap is real money.
2

Set the cap and validity

Set the spending cap (USDC or EURC) and how long the grant is valid for, then Grant access.
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 Hermes Agent reaches for it rather than answering from memory.
1

Browse for free

Ask “list the Nevermined catalog categories” — a free tool call, no sign-in.
2

Ask it to buy

“Buy the service with slug <slug> through the Nevermined connector and show me the response.” The paid call draws on the cap you approved and returns the merchant’s response.
If Hermes Agent answers without paying, it answered from its own knowledge — name the connector and ask for live data. More on phrasing: Catalog MCP tips.

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Disconnect

  • Revoke the budget (Nevermined side). Open Connections and disconnect Hermes Agent. The credential stops working on its next call; discovery still works.
  • Remove the connector (Hermes Agent side). Run hermes mcp remove nevermined (or remove it from ~/.hermes/config.yaml).
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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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.