Quickstart

You need an MCP client and a wallet on Base that can sign messages. The agent does every step itself. You only add the server.

1. Add the MCP server

In Claude Code, run this once in a terminal:

claude mcp add --transport http 402lounge https://mcp.402lounge.com/mcp

Clients that read a JSON file take the same URL:

{
  "mcpServers": {
    "402lounge": { "url": "https://mcp.402lounge.com/mcp" }
  }
}

Cursor, OpenClaw, Hermes, Grok and others are on the MCP page, each with its exact setup.

2. Let the agent sign up

Tell it "sign up at 402lounge". It calls lounge.requirements for the current versions of the terms, then lounge.signup twice:

lounge.signup {
  name: "Research",
  address: "0x4b7e1d2c90a6f3e58d1c7b20e9a4f6d3c8b51e07",
  accept: { terms: "<version>", privacy: "<version>", business: true }
}

The first call answers auth_required with a challenge. The wallet signs challenge.message, and the same call with proof: {message, signature} creates the account. The answer carries a session token. The agent keeps it and sends it as Authorization: Bearer lg_... from then on.

The account is a company from this moment, named after the agent. Accounts and sign-in has the details.

3. Pay as usual, then report it

Your agent pays a seller over x402 exactly as before. The seller's answer carries the PAYMENT-RESPONSE header with the transaction hash. Right after, the agent calls:

receipts.record {
  tx_hash: "0xbcbca5c39efb57034965b0e84225f6264840c0c940f58e0980844a2bc888da4c",
  resource_url: "https://api.northpine.example/metrics/v2/projects",
  amount: "0.15"
}

The answer says pending until Base confirms the transfer.

4. See the receipt

The indexer reads Base every minute and waits for 12 confirmations. Then receipts.list shows the receipt: the seller from the register, what was bought, the agent that paid and a EUR value at the ECB rate of the day, marked provisional. lounge.dashboard.link gives the human behind the agent a browser link into the dashboard, valid for ten minutes.

5. Add the company data

Receipts work without it. For one voucher per seller every month, an admin agent calls company.update with the legal name, address, country and email, plus a VAT id if the company has one. Companies, agents and people says what each field does.