x402 payments for the Blockscout Pro API

cast wallet new

echo 'X402_PRIVATE_KEY=0xYOUR_PRIVATE_KEY_HERE' >> ~/.hermes/.env

pip install "x402[requests]" eth_account

#!/usr/bin/env python3
"""
Usage: x402_pay.py <url>

Calls a Blockscout Pro API URL, paying via x402 with the wallet in
$X402_PRIVATE_KEY if the endpoint returns a 402. Prints a single JSON
object to stdout with the response body and payment settlement info.
"""
import json
import os
import sys

from eth_account import Account
from x402 import x402ClientSync
from x402.http import x402HTTPClientSync
from x402.http.clients import x402_requests
from x402.mechanisms.evm import EthAccountSigner
from x402.mechanisms.evm.exact.register import register_exact_evm_client


def call_with_safe_retry(session, url, max_retries=2):
    response = session.get(url)
    signature = response.request.headers.get("PAYMENT-SIGNATURE")

    attempt = 0
    while (
        response.status_code >= 500
        and "PAYMENT-RESPONSE" not in response.headers
        and signature
        and attempt < max_retries
    ):
        attempt += 1
        response = session.get(url, headers={"PAYMENT-SIGNATURE": signature})

    return response


def main():
    if len(sys.argv) != 2:
        print(json.dumps({"error": "usage: x402_pay.py <url>"}))
        sys.exit(1)

    url = sys.argv[1]

    client = x402ClientSync()
    account = Account.from_key(os.environ["X402_PRIVATE_KEY"])
    register_exact_evm_client(client, EthAccountSigner(account))
    http_client = x402HTTPClientSync(client)

    with x402_requests(client) as session:
        response = call_with_safe_retry(session, url)

        settle_response = None
        if response.ok:
            settle_response = http_client.get_payment_settle_response(
                lambda name: response.headers.get(name)
            )

        print(json.dumps({
            "status": response.status_code,
            "body": response.text,
            "payment": settle_response,
        }))


if __name__ == "__main__":
    main()

chmod +x ~/.hermes/skills/x402_pay.py

cat >> ~/.hermes/AGENTS.md << 'EOF'

## x402 Payments
To call a Blockscout Pro API endpoint that may require payment, run:

    python3 ~/.hermes/skills/x402_pay.py "<url>"

This handles the 402 challenge, EIP-3009 signing, safe 5xx retries, and
payment verification. Parse its JSON stdout for `status`, `body`, and
`payment` (null if no payment was required).
EOF

{
  "status": 200,
  "body": "{...token data...}",
  "payment": {
    "success": true,
    "transaction": "0x339bccd1664bd7398add3df2450c9ca0acab9abf748f86dbbd6de1b78b9bbe04",
    "network": "eip155:8453",
    "payer": "0xe7878baE142Ef38B557540Ae62E5118A0da4a13D"
  }
}