ToolVet
78trust / 100

Allowance Exposure

by Agent Mercantile in Onchain & crypto

x402 APIPassing, checked 2 h ago

Inspect one Base ERC-20 owner/token/spender allowance with same-block balance and token metadata plus factual exposure flags. No wallet access, signing, or transaction execution. Call when you need a same-block Base allowance-versus-balance snapshot for one owner/token/spender triple.

POST
https://api.agentmercantile.com/v1/allowance-exposure
Price
$0.01
per call in USDC
Uptime
100%
last 30 days
Response time
281 ms
430 ms slowest 5%
Last check
Passed
2 h ago, next any minute now

Run a free test callHow to call it

Reliability

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Status and outage history · Atom feed · Watch with other listings

How to call it

POST https://api.agentmercantile.com/v1/allowance-exposure

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.

POST https://api.agentmercantile.com/v1/allowance-exposure
content-type: application/json

{
  "owner": "0x0000000000000000000000000000000000000001",
  "spender": "0x0000000000000000000000000000000000000002",
  "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
}

Parameters

ParameterTypeRequiredDescription
ownerstringYesERC-20 token owner address. 0x-prefixed 20-byte EVM address.
spenderstringYesSpender address. 0x-prefixed 20-byte EVM address.
tokenstringYesERC-20 token contract. 0x-prefixed 20-byte EVM address. Zero address is rejected.

Example response

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

Example response, 31 lines
{
  "allowance_adjusted": "1",
  "allowance_balance_exposure_adjusted": "0.5",
  "allowance_balance_exposure_raw": "500000",
  "allowance_covers_current_balance": true,
  "allowance_raw": "1000000",
  "balance_adjusted": "0.5",
  "balance_raw": "500000",
  "block_number": "12345678",
  "effectively_unlimited": false,
  "evidence": {
    "block_number": "12345678",
    "same_block_reads": true,
    "token_code_present": true
  },
  "limitations": [
    "Base Mainnet only (eip155:8453)."
  ],
  "machine": "VM02",
  "max_uint256_approval": false,
  "methodology_version": "allowance-exposure-0.1.0",
  "network": "eip155:8453",
  "owner": "0x0000000000000000000000000000000000000001",
  "spender": "0x0000000000000000000000000000000000000002",
  "status": "OK",
  "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
  "token_metadata": {
    "decimals": 6,
    "symbol": "USDC"
  }
}

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 -X POST 'https://api.agentmercantile.com/v1/allowance-exposure' \
  -H 'content-type: application/json' \
  --data-raw '{"owner":"0x0000000000000000000000000000000000000001","spender":"0x0000000000000000000000000000000000000002","token":"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 - -X POST 'https://api.agentmercantile.com/v1/allowance-exposure' \
  -H 'content-type: application/json' \
  --data-raw '{"owner":"0x0000000000000000000000000000000000000001","spender":"0x0000000000000000000000000000000000000002","token":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"}' \
  | 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%2Fapi.agentmercantile.com%2Fv1%2Fallowance-exposure&method=POST
const res = await pay("https://api.agentmercantile.com/v1/allowance-exposure", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "owner": "0x0000000000000000000000000000000000000001",
    "spender": "0x0000000000000000000000000000000000000002",
    "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
  }),
});
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.post(
        "https://api.agentmercantile.com/v1/allowance-exposure",
        json={
            "owner": "0x0000000000000000000000000000000000000001",
            "spender": "0x0000000000000000000000000000000000000002",
            "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
        },
    )
    print(res.status_code, res.text)

Security scan

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