> ## Documentation Index
> Fetch the complete documentation index at: https://nevermined.ai/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Using the Catalog from your web assistant

> Connect the Nevermined Catalog to a web AI assistant like Claude.ai or ChatGPT — paste one URL, approve one spending cap, and it pays for services as it works.

Web AI assistants — **Claude.ai**, **ChatGPT**, **LangSmith Fleet** — can browse the [Nevermined Catalog](/docs/products/catalog/overview) and pay for services as they work, without you ever handing over an API key. You paste one URL, approve a single spending cap, and the assistant does the rest. This is the no-code, in-the-browser counterpart to [Using the Catalog from a harness](/docs/products/catalog/from-a-harness).

<Note>
  This is the **buyer** side — giving an assistant you already use a wallet. Driving the Catalog from your own code or a coding agent? See [Using the Catalog from a harness](/docs/products/catalog/from-a-harness). The exhaustive per-host click paths (name warnings, Fleet's OAuth provider table, every refusal code) live on the [Catalog MCP](/docs/products/catalog/mcp#connect-from-your-assistant) page — this page is the walkthrough that gets you there.
</Note>

## See it in action

Give an assistant a budget and ask it to go and buy what it needs — a search, a page fetch, a live forecast — and it pays per call, for a few cents, against a cap you set.

<Frame caption="Your AI assistant can now pay for things.">
  <iframe src="https://www.youtube.com/embed/KJxlW6qI6So" title="Your AI assistant can now pay for things" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowFullScreen style={{ width: "100%", aspectRatio: "16 / 9", borderRadius: "0.5rem", border: 0, display: "block" }} />
</Frame>

The per-assistant walkthroughs are below, and collected on the [Catalog videos](/docs/products/catalog/videos#connect-from-your-assistant) page.

## What you get

* **No API key, no client secret, no vendor account.** Claude and ChatGPT discover everything from one URL; Fleet takes the endpoints once.
* **One consent screen** sets who can spend, how much, and for how long. The grant *is* the credential — your assistant never holds a key.
* **Every payment is on the record** — merchant, amount, transaction hash, and what's left of the cap — in your [payment ledger](/docs/products/catalog/router/ledger).
* **Your assistant can pay any service it discovers**, not a fixed list you wire up in advance.
* **Revoking is instant and self-service**, from [Connections](https://nevermined.app/connections) in the Nevermined app.

## How it works — three moves

<Steps>
  <Step title="Point your assistant at one URL">
    The Catalog MCP server URL. In **Claude** and **ChatGPT** that's the whole configuration — paste it, leave the OAuth client ID and secret empty, and the assistant discovers the rest. **LangSmith Fleet** doesn't discover, so you enter its endpoints once.
  </Step>

  <Step title="Browse the Catalog for free">
    Discovery needs no sign-in. Ask for the categories, search for a service, read its price — all before you approve anything.
  </Step>

  <Step title="Approve a spending cap, once">
    Nevermined's consent page opens: check the **Sandbox / Live** badge, set the **cap** and how long it's **valid for**, then **Grant access**. That approval is a **commerce grant** — it spends only from the budget you just approved, only through the [Router](/docs/products/catalog/router/overview), and you can revoke it any time. Your assistant retries the call it was blocked on.
  </Step>
</Steps>

<Tip>
  **Ask in a way that makes the assistant reach for the Catalog.** All three will happily answer from their own knowledge and charge nothing — which looks like a broken connector and isn't. Name the connector in the prompt (*"using the Nevermined connector, …"*), ask for something only live data can answer, and name services in single words. More on phrasing in the [Catalog MCP tips](/docs/products/catalog/mcp#connect-from-your-assistant).
</Tip>

## Pick your assistant

The click paths differ; the mechanics underneath are identical. Each tab has the short version and a link to the full walkthrough.

<Tabs>
  <Tab title="Claude (claude.ai)">
    <Steps>
      <Step title="Add the connector">
        **Settings → Connectors → Add custom connector.** Name it and paste the server URL. Leave the OAuth client ID and secret **empty** — Claude identifies itself to Nevermined on its own, so there's nothing to register.
      </Step>

      <Step title="Ask for something free, then ask it to buy">
        Enable the connector and ask *"list the Nevermined catalog categories"* (no sign-in). Then ask it to buy a service — the paid call returns `401` and Claude shows an inline **Connect** card.
      </Step>

      <Step title="Approve the cap">
        **Connect** → the consent page opens. Set the **cap** and **validity**, **Grant access**, and Claude retries the call with the grant.
      </Step>
    </Steps>

    <Frame caption="Connect to the Catalog from claude.ai.">
      <iframe src="https://www.youtube.com/embed/uW-_V-dOeSw" title="Connect to the Catalog from claude.ai" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowFullScreen style={{ width: "100%", aspectRatio: "16 / 9", borderRadius: "0.5rem", border: 0, display: "block" }} />
    </Frame>

    Full click path: [Catalog MCP → Claude](/docs/products/catalog/mcp#connect-from-your-assistant).
  </Tab>

  <Tab title="ChatGPT">
    <Steps>
      <Step title="Turn on Developer mode">
        **Settings → Security and login → Developer mode** (needs a paid plan). *Plugins* then appears in the sidebar.
      </Step>

      <Step title="Create an MCP app">
        **Plugins → ＋ → Create app → Create MCP app.** Paste the server URL, choose **OAuth**, and leave the client ID and secret empty — ChatGPT discovers the OAuth settings from the server.
      </Step>

      <Step title="Approve the cap at creation">
        ChatGPT runs the consent **immediately**, before any tool call. Set the **cap** and **validity**, **Grant access**, and the plugin shows as connected.
      </Step>
    </Steps>

    <Frame caption="Connect to the Catalog from ChatGPT.">
      <iframe src="https://www.youtube.com/embed/fI_llp5BBYM" title="Connect to the Catalog from ChatGPT" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowFullScreen style={{ width: "100%", aspectRatio: "16 / 9", borderRadius: "0.5rem", border: 0, display: "block" }} />
    </Frame>

    <Warning>
      **Choose the plugin name carefully — a ChatGPT plugin cannot be deleted or renamed.** Full detail and the rest of the dialog: [Catalog MCP → ChatGPT](/docs/products/catalog/mcp#connect-from-your-assistant).
    </Warning>
  </Tab>

  <Tab title="LangSmith Fleet">
    Fleet doesn't discover, so you create two objects once: a LangSmith **OAuth provider** (ID exactly `nevermined`) and a **custom MCP server** pointed at the `mcp.api.<tier>` host so Fleet is challenged on connect.

    <Steps>
      <Step title="Create the OAuth provider">
        **Settings → OAuth providers → New** — provider ID `nevermined`, client ID `langsmith-fleet`, a placeholder secret, the authorization and token URLs, PKCE method **S256**. The exact values are in the provider table on the Catalog MCP page.
      </Step>

      <Step title="Add the MCP server">
        **Settings → Integrations → Add custom MCP** — paste `https://mcp.api.live.nevermined.app/mcp` (or the sandbox host), choose **OAuth 2.1 (Manual)**, and select the provider from step 1.
      </Step>

      <Step title="Connect and approve the cap">
        Fleet asks *Connect now?* → the consent page opens. Set the **cap** and **validity**, **Grant access**.
      </Step>
    </Steps>

    <Frame caption="Connect the Catalog to a LangSmith Fleet agent.">
      <iframe src="https://www.youtube.com/embed/A7HcBsnRYG8" title="Connect the Catalog to a LangSmith Fleet agent" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" allowFullScreen style={{ width: "100%", aspectRatio: "16 / 9", borderRadius: "0.5rem", border: 0, display: "block" }} />
    </Frame>

    Full provider table, the `mcp.api.` host requirement, and the cached-credential gotcha: [Catalog MCP → LangSmith Fleet](/docs/products/catalog/mcp#connect-from-your-assistant).
  </Tab>
</Tabs>

### Which URL to point at

| Where you point it                            | Server URL                                                                               |
| --------------------------------------------- | ---------------------------------------------------------------------------------------- |
| **Sandbox** — the right place for a first run | `https://mcp.sandbox.nevermined.app/mcp`                                                 |
| **Live** — real merchants, real money         | `https://mcp.live.nevermined.app/mcp`                                                    |
| **LangSmith Fleet** (either tier)             | `https://mcp.api.sandbox.nevermined.app/mcp` · `https://mcp.api.live.nevermined.app/mcp` |

Fleet needs the `mcp.api.` host so it's challenged for auth on connect; Claude and ChatGPT use the plain host and are prompted when they first try to pay.

## What the consent screen asks

One screen, and it's the only place a human is required. **You set** the spending **cap** (in USDC or EURC) and how long the grant is **valid for**. The **environment** badge (Sandbox or Live) and **who is asking** are shown, not chosen. Before you grant, know that:

* On **Live**, the cap is real money.
* The assistant may pay **any service it can reach**, not a fixed list.
* **Nevermined's routing fee comes out of the same cap** — the cap is the total debited, not what merchants receive.
* The grant also lets the assistant read your payment history and wallet balance. **The cap bounds what it can spend, not what it can see.**

Granting creates a budget confined to that cap and window, funded from your own wallet, and hands the assistant a credential that spends only through it — never a card mandate. Full breakdown of the consent screen: [Catalog MCP → What the consent page asks](/docs/products/catalog/mcp#what-the-consent-page-asks). What happens once the cap is spent or the window ends: [When the grant runs out](/docs/products/catalog/mcp#when-the-grant-runs-out).

## Revoke any time

Open [Connections](https://nevermined.app/connections) in the Nevermined app and disconnect the assistant — the credential stops working on its next call. To spend again after that, 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.

## Next

<CardGroup cols={2}>
  <Card title="Catalog MCP — full click paths" icon="plug" href="/docs/products/catalog/mcp#connect-from-your-assistant">
    Every step for Claude, ChatGPT and Fleet, the consent details, and every refusal code.
  </Card>

  <Card title="Using the Catalog from a harness" icon="terminal" href="/docs/products/catalog/from-a-harness">
    The code-free playbook for driving discovery and payment from your own agent or coding harness.
  </Card>

  <Card title="Catalog videos" icon="circle-play" href="/docs/products/catalog/videos#connect-from-your-assistant">
    The connect walkthroughs for each assistant, plus the Catalog overview and outcome examples.
  </Card>

  <Card title="Router: pay" icon="route" href="/docs/products/catalog/router/overview">
    Delegations, the spending cap, the rails, and every refusal code.
  </Card>
</CardGroup>