> ## 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.

> ## Agent Instructions
> If you are an agent buying services: start with these steps. Every page has a .md version.
> 1. Install the Catalog MCP (live server https://mcp.live.nevermined.app/mcp, sandbox server https://mcp.sandbox.nevermined.app/mcp; rehearse on sandbox with a sandbox API key before live, as keys work only in their own environment; Claude Code and Cursor commands, Codex config.toml entry): https://nevermined.ai/docs/products/catalog/mcp.md
> 2. Get an API key: https://nevermined.ai/docs/agents-guide/get-api-key.md
> 3. Enroll a card and create a delegation (a payment method plus a spend mandate: an amount, an expiry and a number of purchases): https://nevermined.ai/docs/agents-guide/enroll-card.md
> 4. Buy and call a paid agent over x402: https://nevermined.ai/docs/getting-started/ai-agent-purchase.md
> SDK quickstart: https://nevermined.ai/docs/integrate/quickstart/typescript.md. Pricing: https://nevermined.ai/pricing/

# Connect the Catalog from v0

> Connect the Nevermined Catalog to v0 — add one MCP server, approve one spending cap, and v0 pays for services as it works. No API key.

v0 can browse the [Nevermined Catalog](/docs/products/catalog/overview) and pay for services as it works, without you handing over an API key. You add one server, approve a single spending cap, and v0 does the rest. This is the per-host walkthrough; for the concept and the other assistants, see [Using the Catalog from your web assistant](/docs/products/catalog/from-your-web-assistant).

## Before you connect

<Steps>
  <Step title="A Nevermined account">
    Free, at [nevermined.app](https://nevermined.app). You never share an API key with v0 — the consent cap *is* the credential.
  </Step>

  <Step title="A funded wallet">
    A paid call draws on a **spending cap** you approve during connect — a [commerce grant](/docs/mcp/catalog-mcp/overview#auth-&-transport): 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](/docs/products/catalog/router/quickstart#3-fund-your-wallet). You approve the cap itself in [Approve the spending cap](#approve-the-spending-cap).
  </Step>
</Steps>

<Note>
  Start on **sandbox**, where you use testnet funds and nothing costs real money, before you point v0 at **live**.
</Note>

## Add the Catalog to v0

<Steps>
  <Step title="Add the Catalog as a custom MCP server">
    In a v0 chat, open the **+** menu in the prompt form and choose **MCPs → add a custom server**. Enter the server URL for your environment and pick **OAuth** as the authentication method:

    | Environment | 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` |
  </Step>

  <Step title="Authorize">
    Complete the **OAuth** flow v0 shows and grant the permissions it asks for — this opens Nevermined's consent page. The first **paid** call is what triggers it; browsing and free tools need no sign-in.
  </Step>
</Steps>

<Note>
  If the **+ → MCPs** custom-server dialog is not available in your v0 build, check v0's current MCP docs — the custom-server UI is still rolling out.
</Note>

## Approve the spending cap

v0 opens Nevermined's consent page on your first **paid** call. Discovery and free tools need no credential. It is the one place a human is required.

<Steps>
  <Step title="Check who and where">
    The page shows the **Sandbox / Live** badge and **who is asking**. On **live**, the cap is real money.
  </Step>

  <Step title="Set the cap and validity">
    Set the **spending cap** (USDC or EURC) and how long the grant is **valid for**, then **Grant access**.
  </Step>
</Steps>

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. 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](/docs/mcp/catalog-mcp/overview#what-the-consent-page-asks).

## Make your first paid call

Ask for something only live data can answer, and name the connector so v0 reaches for it rather than answering from memory.

<Steps>
  <Step title="Browse for free">
    Ask *"list the Nevermined catalog categories"* — a free tool call, no sign-in.
  </Step>

  <Step title="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.
  </Step>
</Steps>

<Tip>
  If v0 answers without paying, it answered from its own knowledge — name the connector and ask for live data. More on phrasing: [Catalog MCP tips](/docs/mcp/catalog-mcp/overview#connect-from-your-assistant).
</Tip>

## Disconnect

* **Revoke the budget (Nevermined side).** Open [Connections](https://nevermined.app/connections) and disconnect v0. The credential stops working on its next call; discovery still works.
* **Remove the connector (v0 side).** Remove or disable the Nevermined custom server from the **+ → MCPs** menu in v0.

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.

## Next

<CardGroup cols={2}>
  <Card title="Using the Catalog from your web assistant" icon="comments" href="/docs/products/catalog/from-your-web-assistant">
    The concept and the other assistants.
  </Card>

  <Card title="Catalog MCP — full reference" icon="plug" href="/docs/mcp/catalog-mcp/overview#connect-from-your-assistant">
    Every click path, the consent details, and every refusal code.
  </Card>
</CardGroup>


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