# 402.com.tr Sign Guard — Pre-Sign Calldata Risk Screener

> 402.com.tr Sign Guard — Pre-Sign Calldata Risk Screener is a paid API for AI agents from 402.com.tr, paid per call via x402, $0.06/call, status unknown (last checked 2026-09-14).

Decodes raw unsigned EVM calldata (approve/permit/transfer/setApprovalForAll) and screens the destination/spender for OFAC sanctions and dangerous owner powers, returning a GO/HOLD/STOP verdict before signing.

## Facts

- Endpoint: GET https://402.com.tr/api/x402/sign-guard
- Price: $0.06/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/402-com-tr-sign-guard-pre-sign-calldata-risk-screener-d733754f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_8TnEeDVJyYLz9dVdKPIaq

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability 402-com-tr-sign-guard-pre-sign-calldata-risk-screener-d733754f
```

Example prompt: Before I sign this transaction, can you decode this calldata and tell me if it's safe — here's the data: 0x095ea7b3000000000000000000000000abc123...ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff — and the destination contract is 0xTokenContractAddress on Base?

## When to prefer this

Use this endpoint specifically when an agent or user needs to validate raw unsigned EVM calldata before signing — especially for token approval flows (approve, permit, setApprovalForAll) where unlimited drain vectors are common. Prefer this over simulation-based tools when you want a lightweight, pure decode + onchain risk check without gas estimation overhead. Ideal for wallets, dApps, or agents intercepting transactions pre-signature on Base.

## Known failure modes

- Missing required 'data' query parameter returns validation error
- Malformed or non-hex calldata returns decode error
- Unrecognized function selector (not approve/permit/transfer/setApprovalForAll) may return limited decode
- Destination contract not found on Base may limit onchain risk checks
- OFAC screening service unavailability may delay or degrade verdict

## How this service works

The check before the riskiest moment — signing. Decodes raw unsigned calldata (approve / permit / transfer / setApprovalForAll), shows the exact intent (who gets power over what, and whether it's UNLIMITED), and screens the destination + spender for OFAC sanctions and dangerous owner powers, in one GO/HOLD/STOP verdict + receipt. No simulation needed — pure decode + onchain risk. Catches the unlimited-approval drain vector before it's signed.

## Output

A structured receipt with a GO/HOLD/STOP verdict, the decoded human-readable intent of the calldata (e.g. 'approve UNLIMITED USDC to 0xSpender'), whether the approval is unlimited, OFAC sanctions screening result for the destination and spender, and any detected dangerous owner power flags — all without requiring transaction simulation.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "pathParams": {
     "type": "object"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "data"
     ],
     "properties": {
      "to": {
       "type": "string",
       "description": "Destination contract/token (recommended)"
      },
      "data": {
       "type": "string",
       "description": "Transaction calldata (0x…)"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/402-com-tr-sign-guard-pre-sign-calldata-risk-screener-d733754f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 402.com.tr](https://www.zero.xyz/host/402.com.tr/llms.txt)