x402 MCP Server

How payment fits an MCP request

1. The client requests a protected resource.
2. The server returns payment instructions instead of the resource.
3. The wallet reviews and authorizes the payment.
4. The client retries the request and inspects the response.

The payment response and the returned work should be checked separately.

What the client needs

The client needs to understand the payment challenge, use a wallet and network it supports, and resume the same request after payment. A service can still refuse or fail the underlying call, so inspect its response separately.

Check the current client and server documentation before enabling unattended payment.

What the receipt shows

The payment challenge describes the request and the amount due. A separate work receipt records the tool call and its returned status; it should not be treated as a wallet settlement confirmation.

Open the saved call at the receipt checker to inspect its recorded fields.

Try one call

Start with a small, non-sensitive request and review the payment prompt before authorizing it. After the client returns a result, open the linked receipt and compare the recorded status with the response you received.

Never approve a charge just to test a checkout flow.