Token Briefs Brief

{
  "brief": {
    "baselineStatus": "no_baseline",
    "changes": [],
    "schemaVersion": "1",
    "snapshot": {
      "claims": [
        {
          "claim": "Circle lists this exact contract as USDC on Base.",
          "evidenceIds": [
            "registry-source"
          ],
          "explanation": "Exact contract appears in the official mainnet registry.",
          "state": "supported"
        }
      ],
      "evidence": [
        {
          "excerpt": "Base mainnet registry entry for this contract.",
          "id": "registry-source",
          "url": "https://developers.circle.com/stablecoins/usdc-contract-addresses"
        }
      ],
      "facts": {
        "decimals": "6"
      },
      "token": {
        "contractAddress": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        "network": "eip155:8453"
      }
    },
    "unknowns": [
      "Reserves, safety, liquidity and holders are not assessed."
    ]
  },
  "receipt": {
    "status": "settled",
    "transactionHash": "0xaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
  }
}

# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://engine.beehivewebstudio.com/v1/token-briefs/brief?claim=Circle+lists+this+exact+contract+as+USDC+on+Base.&contractAddress=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913'

# 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 - 'https://engine.beehivewebstudio.com/v1/token-briefs/brief?claim=Circle+lists+this+exact+contract+as+USDC+on+Base.&contractAddress=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913' \
  | 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 $0.25 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.25" });
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 $0.25 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fengine.beehivewebstudio.com%2Fv1%2Ftoken-briefs%2Fbrief
const res = await pay("https://engine.beehivewebstudio.com/v1/token-briefs/brief?claim=Circle+lists+this+exact+contract+as+USDC+on+Base.&contractAddress=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913");
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 $0.25 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.25"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.get("https://engine.beehivewebstudio.com/v1/token-briefs/brief?claim=Circle+lists+this+exact+contract+as+USDC+on+Base.&contractAddress=0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913")
    print(res.status_code, res.text)