Security · x402 · early usage

Deterministic pre-sign risk screening for unsigned Base EVM transactions

Deterministic pre-sign risk screening for unsigned Base EVM transactions. Detects ERC20 transfers, token approvals, unlimited approvals, setApprovalForAll, malformed calldata and OFAC SDN and configured address matches. Returns machine-readable ALLOW, REVIEW…

by agent-sign-guard-main-production.up.railway.app · discovered, not yet claimed by its owner · updated 2026-09-26

30d calls7

30d payers7

MethodPOST

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

Tags: bazaar · builder-code · eip2612GasSponsoring · erc20ApprovalGasSponsoring

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-09-26

Input example from Bazaar metadata

{}

No output exampleProvider did not publish one in Bazaar metadata.

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/57076.json for the price and payment options.
Pay. Call GET https://agent-sign-guard-main-production.up.railway.app/risk-check. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base Sepolia, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: see accepts
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base Sepolia
Demand: 7 calls · 7 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base Sepolia eip155:84532	USDC	10000	0xf211b7F28bD788f8E76C7a1d7440601E00647526	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:84532",
    "payTo": "0xf211b7F28bD788f8E76C7a1d7440601E00647526",
    "asset": "0x036CbD53842c5426634e7929541eC2318f3dCF7e",
    "amount": "10000",
    "maxTimeoutSeconds": 300
  }
]

Examples

curl

curl "https://agent-sign-guard-main-production.up.railway.app/risk-check"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://agent-sign-guard-main-production.up.railway.app/risk-check");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://agent-sign-guard-main-production.up.railway.app/risk-check")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: agent-sign-guard-main-production.up.railway.app
Endpoint: https://agent-sign-guard-main-production.up.railway.app/risk-check
Machine-readable: /resources/57076.json