X402 Mcp Sampling Exposure Card

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://api.blockchainmoneymap.com/api/x402/x402-mcp-sampling-exposure-card' \
  -H 'content-type: application/json' \
  --data-raw '{"facts":{"approvalFlow":"client asks user before sampling","mcpCapabilities":{"approvalRequired":true,"promptExposure":"summaries only","sampling":true},"promptExposureNotes":"No raw secrets; prompt summary only.","samplingDescription":"Server may request client sampling after user approval."},"mode":"audit"}'

# x402 v2 sends the challenge base64-encoded in the PAYMENT-REQUIRED header (v1 sends it in the body).
# To read the header:
curl -sS -g -o /dev/null -D - -X POST 'https://api.blockchainmoneymap.com/api/x402/x402-mcp-sampling-exposure-card' \
  -H 'content-type: application/json' \
  --data-raw '{"facts":{"approvalFlow":"client asks user before sampling","mcpCapabilities":{"approvalRequired":true,"promptExposure":"summaries only","sampling":true},"promptExposureNotes":"No raw secrets; prompt summary only.","samplingDescription":"Server may request client sampling after user approval."},"mode":"audit"}' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode

// npm i @x402/fetch @x402/evm viem
import { wrapFetchWithPayment, x402Client } from "@x402/fetch";
import { registerExactEvmScheme } from "@x402/evm/exact/client";
import { privateKeyToAccount } from "viem/accounts";

// Pays at most $0.01 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.01" });
registerExactEvmScheme(client, { signer: privateKeyToAccount(process.env.EVM_PRIVATE_KEY) });
const pay = wrapFetchWithPayment(fetch, client);

// Not sure it's safe to pay? ToolVet checks it first for $0.005. Pay for that from a separate
// client: this one is capped at $0.01 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fapi.blockchainmoneymap.com%2Fapi%2Fx402%2Fx402-mcp-sampling-exposure-card&method=POST
const res = await pay("https://api.blockchainmoneymap.com/api/x402/x402-mcp-sampling-exposure-card", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "facts": {
      "approvalFlow": "client asks user before sampling",
      "mcpCapabilities": {
        "approvalRequired": true,
        "promptExposure": "summaries only",
        "sampling": true
      },
      "promptExposureNotes": "No raw secrets; prompt summary only.",
      "samplingDescription": "Server may request client sampling after user approval."
    },
    "mode": "audit"
  }),
});
console.log(res.status, await res.text());

# pip install "x402[requests,evm]"
import os
from eth_account import Account
from x402 import x402ClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client

# Pays at most $0.01 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.01"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://api.blockchainmoneymap.com/api/x402/x402-mcp-sampling-exposure-card",
        json={
            "facts": {
                "approvalFlow": "client asks user before sampling",
                "mcpCapabilities": {
                    "approvalRequired": True,
                    "promptExposure": "summaries only",
                    "sampling": True,
                },
                "promptExposureNotes": "No raw secrets; prompt summary only.",
                "samplingDescription": "Server may request client sampling after user approval.",
            },
            "mode": "audit",
        },
    )
    print(res.status_code, res.text)