ToolVet
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Sign Decode

by what-am-i-signing in Onchain & crypto

x402 APIPassing, checked 2 h ago

Decode an EVM signature request (EIP-712 typed data, Permit/Permit2, or ERC-20 approve calldata) into a structured intent: what token, which spender, how much, until when, plus risk_flags and an action_hint. Deterministic, no LLM. Answers an agent's question 'what am I about to sign?'

POST https://x402-store.dgdb.workers.dev/v1/sign-decode

Last 30 days

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Status and outage history · Atom feed

Uptime
100%
Response time
360 ms typical, 616 ms slowest 5%
Last check
2 h ago
Next check
any minute now

How to call it

POST https://x402-store.dgdb.workers.dev/v1/sign-decode

Each call costs $0.005 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://x402-store.dgdb.workers.dev/v1/sign-decode
content-type: application/json

{
  "domain": {
    "chainId": 8453,
    "name": "Permit2",
    "verifyingContract": "0x000000000022D473030F116dDEE9F6B43aC78BA3"
  },
  "message": {
    "details": {
      "amount": "1461501637330902918203684832716283019655932542975",
      "expiration": "1781176678",
      "nonce": "0",
      "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
    },
    "sigDeadline": "1749722278",
    "spender": "0x66a9893cC07D91D95644AEDD05D03f95e1dBA8Af"
  },
  "primaryType": "PermitSingle"
}

Parameters

ParameterTypeRequiredDescription
calldatastringNo
domainobjectNo
messageobjectNo
primaryTypestringNo

Example response

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

{
  "action_hint": "ask_for_confirmation",
  "amount": "unlimited",
  "confidence": 1,
  "expires_at": "2026-07-12T11:17:58Z",
  "intent": "grant_allowance",
  "risk_flags": [
    "unlimited_allowance"
  ],
  "spender": "0x66a9893cC07D91D95644AEDD05D03f95e1dBA8Af",
  "spender_known": "Uniswap Universal Router v2",
  "standard": "Permit2-AllowanceTransfer (PermitSingle)",
  "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
}

Call it from code

The curl command shows the payment challenge. The JavaScript and Python versions pay and call, and never pay more than $0.005.

curl: see the payment challenge
# bash or zsh: see the payment challenge. Nothing is charged.
curl -sS -g -i -X POST 'https://x402-store.dgdb.workers.dev/v1/sign-decode' \
  -H 'content-type: application/json' \
  --data-raw '{"domain":{"chainId":8453,"name":"Permit2","verifyingContract":"0x000000000022D473030F116dDEE9F6B43aC78BA3"},"message":{"details":{"amount":"1461501637330902918203684832716283019655932542975","expiration":"1781176678","nonce":"0","token":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"},"sigDeadline":"1749722278","spender":"0x66a9893cC07D91D95644AEDD05D03f95e1dBA8Af"},"primaryType":"PermitSingle"}'

# 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://x402-store.dgdb.workers.dev/v1/sign-decode' \
  -H 'content-type: application/json' \
  --data-raw '{"domain":{"chainId":8453,"name":"Permit2","verifyingContract":"0x000000000022D473030F116dDEE9F6B43aC78BA3"},"message":{"details":{"amount":"1461501637330902918203684832716283019655932542975","expiration":"1781176678","nonce":"0","token":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"},"sigDeadline":"1749722278","spender":"0x66a9893cC07D91D95644AEDD05D03f95e1dBA8Af"},"primaryType":"PermitSingle"}' \
  | 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 $0.005 per call.
const client = new x402Client().setSpendControls({ maxAmountPerPayment: "$0.005" });
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 $0.005 per payment. GET https://toolvet.app/api/v1/check?url=https%3A%2F%2Fx402-store.dgdb.workers.dev%2Fv1%2Fsign-decode&method=POST
const res = await pay("https://x402-store.dgdb.workers.dev/v1/sign-decode", {
  method: "POST",
  headers: { "content-type": "application/json" },
  body: JSON.stringify({
    "domain": {
      "chainId": 8453,
      "name": "Permit2",
      "verifyingContract": "0x000000000022D473030F116dDEE9F6B43aC78BA3"
    },
    "message": {
      "details": {
        "amount": "1461501637330902918203684832716283019655932542975",
        "expiration": "1781176678",
        "nonce": "0",
        "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913"
      },
      "sigDeadline": "1749722278",
      "spender": "0x66a9893cC07D91D95644AEDD05D03f95e1dBA8Af"
    },
    "primaryType": "PermitSingle"
  }),
});
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 $0.005 per call.
client = x402ClientSync().set_spend_controls({"max_amount_per_payment": "$0.005"})
register_exact_evm_client(client, EthAccountSigner(Account.from_key(os.environ["EVM_PRIVATE_KEY"])))

with x402_requests(client) as session:
    res = session.post(
        "https://x402-store.dgdb.workers.dev/v1/sign-decode",
        json={
            "domain": {
                "chainId": 8453,
                "name": "Permit2",
                "verifyingContract": "0x000000000022D473030F116dDEE9F6B43aC78BA3",
            },
            "message": {
                "details": {
                    "amount": "1461501637330902918203684832716283019655932542975",
                    "expiration": "1781176678",
                    "nonce": "0",
                    "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
                },
                "sigDeadline": "1749722278",
                "spender": "0x66a9893cC07D91D95644AEDD05D03f95e1dBA8Af",
            },
            "primaryType": "PermitSingle",
        },
    )
    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 agoPassed402565 ms$0.005
6 h agoPassed402201 ms$0.005
10 h agoPassed402416 ms$0.005
14 h agoPassed402348 ms$0.005
18 h agoPassed402309 ms$0.005
22 h agoPassed402486 ms$0.005
26 h agoPassed402578 ms$0.005
30 h agoPassed402616 ms$0.005
33 h agoPassed402392 ms$0.005
37 h agoPassed402330 ms$0.005
40 h agoPassed402320 ms$0.005
44 h agoPassed402360 ms$0.005
2 days agoPassed402632 ms$0.005
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2 days agoPassed402347 ms$0.005