Use with ChatGPT & Claude

Free services work with a plain HTTP tool. Paid services need an x402 wrapper that holds a wallet — the model never signs.

The key idea

A chat model can call HTTP tools, but it cannot sign crypto payments. So free services work with any HTTP tool, while paid services need a small wrapper that holds a funded wallet and does the x402 pay-and-retry. The model just calls a clean tool with deviceId, serviceId, and params.

Plain ChatGPT / Claude (discovery + free services)

Register two HTTP tools / Custom GPT Actions and you are done — no wallet:

• GET https://device-controller.0xbs.org/public/device/{deviceId} — discovery
• POST https://device-controller.0xbs.org/quote/device/{deviceId}/service/{serviceId} — call

Claude — MCP tool (paid services)

Expose an MCP tool whose handler runs the x402 wrapper and holds the wallet key. Input schema: { deviceId, serviceId, params, username?, password? }.

// mcp handler (holds AGENT_EVM_PRIVATE_KEY / AGENT_SOLANA_PRIVATE_KEY)
import { createSigner, wrapFetchWithPayment, decodeXPaymentResponse,
         type MultiNetworkSigner } from "x402-fetch";

export async function callDeviceService({ deviceId, serviceId, params, username, password }) {
  const evm = await createSigner("base", process.env.AGENT_EVM_PRIVATE_KEY!);
  const svm = await createSigner("solana", process.env.AGENT_SOLANA_PRIVATE_KEY!);
  const fetchWithPay = wrapFetchWithPayment(
    fetch, { evm, svm } as MultiNetworkSigner, 1_000_000n);

  const res = await fetchWithPay(
    `https://device-controller.0xbs.org/quote/device/${deviceId}/service/${serviceId}`,
    { method: "POST",
      headers: { "content-type": "application/json" },
      body: JSON.stringify({ params, username, password }) });

  const xpr = res.headers.get("x-payment-response");
  return { result: await res.json(),
           settlement: xpr ? decodeXPaymentResponse(xpr) : null };
}

ChatGPT — Custom GPT Action (paid services)

Host the same wrapper behind a public URL and register it as an Action. The Action backend holds the wallet key and performs the x402 flow; the GPT only passes deviceId, serviceId, params.

Agent frameworks

Coinbase AgentKit, LangChain/LangGraph, and similar already ship x402 tools. Give the agent a funded wallet and point its x402 tool at the call URL — the model can pay autonomously.

Prefer a machine-readable spec? Point your agent at skills.md — it documents the whole flow in one fetchable file. See also skills.md.