ToolVet
80trust / 100

Counterparty Check

by Base Payee Safety in Onchain & crypto

x402 APIPassing, checked 2 h ago

Check a Base address before an agent pays or approves it. Input: one address. Output: allow or warn. Reports wallet or contract, whether the wallet has sent a transaction, whether a contract already had code 7 days ago, and whether it is a proxy (EIP-1967, EIP-1167, or implementation()). Warns on contract_is_new, proxy, or no_outgoing_transactions. Wallet age is unknown. A deleted contract looks like a wallet. Not proof of theft.

GET
https://base-token-check.fly.dev/v1/counterparty-check
Price
$0.01
per call in USDC
Uptime
100%
last 30 days
Response time
294 ms
378 ms slowest 5%
Last check
Passed
2 h ago, next any minute now

Run a free test callHow to call it

Reliability

All checks passedSome failedAll failedNot checked

Status and outage history · Atom feed

How to call it

GET https://base-token-check.fly.dev/v1/counterparty-check

Each call costs $0.01 in USDC on Base, paid with the request over x402.

Run a free test callOne unpaid request, the way an agent sends it. You see the payment challenge it gets back. Nothing is charged.

Example request

From the listing.

GET https://base-token-check.fly.dev/v1/counterparty-check?address=0x540c2aA2526C9c8c2fb4632f0fED668C36424Cd5

Parameters

ParameterTypeRequiredDescription
addressstringYesWallet or contract on Base to check before paying or approving it.

Example response

The provider's example. We can't check it without paying.

{
  "address": "0x540c2aA2526C9c8c2fb4632f0fED668C36424Cd5",
  "kind": "wallet",
  "reasons": [
    {
      "code": "no_outgoing_transactions",
      "detail": "This wallet has not sent a Base transaction."
    }
  ],
  "verdict": "warn"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.01.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i 'https://base-token-check.fly.dev/v1/counterparty-check?address=0x540c2aA2526C9c8c2fb4632f0fED668C36424Cd5'

# 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://base-token-check.fly.dev/v1/counterparty-check?address=0x540c2aA2526C9c8c2fb4632f0fED668C36424Cd5' \
  | grep -i '^payment-required:' | cut -d' ' -f2 | tr -d '\r' | base64 --decode
JavaScript: pay and call
// 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%2Fbase-token-check.fly.dev%2Fv1%2Fcounterparty-check
const res = await pay("https://base-token-check.fly.dev/v1/counterparty-check?address=0x540c2aA2526C9c8c2fb4632f0fED668C36424Cd5");
console.log(res.status, await res.text());
Python: pay and call
# 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.get("https://base-token-check.fly.dev/v1/counterparty-check?address=0x540c2aA2526C9c8c2fb4632f0fED668C36424Cd5")
    print(res.status_code, res.text)

Security scan

No findings

We scan names, descriptions and tool definitions for hidden instructions and other prompt-injection patterns.

Recent checks

WhenResultHTTPTimePrice
2 h agoPassed402344 ms$0.01
6 h agoPassed402367 ms$0.01
10 h agoPassed402270 ms$0.01
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