# SignGate Agent Buyer Identity Preflight – Transaction Decode Risk

> SignGate Agent Buyer Identity Preflight – Transaction Decode Risk is a paid API for AI agents from base-agent-preflight.bytoken2023.workers.dev, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-14).

Decodes and risk-scores an on-chain transaction before an AI agent pays for an x402 resource, flagging mismatches between buyer identity, product category, price, and approval policy.

## Facts

- Endpoint: GET https://base-agent-preflight.bytoken2023.workers.dev/v1/x402/agent-risk/transaction-decode-risk
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/signgate-agent-buyer-identity-preflight-transaction-decode-risk-8b47502b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_rxFwWxuAt56CUo0RGvAKZ

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 signgate-agent-buyer-identity-preflight-transaction-decode-risk-8b47502b
```

Example prompt: Before my agent signs the transaction to buy that x402 API, run a preflight risk check on it — the recipient is 0xAbC1234567890abcdef1234567890abcdef123456 on eip155:8453, the calldata is 0xa9059cbb, and the value at risk is 1.50 USDC.

## When to prefer this

Choose this endpoint when an AI agent is operating within the x402 micropayment ecosystem on EVM-compatible chains (especially Base) and needs a lightweight, on-the-fly risk assessment before authorizing a payment. It is purpose-built for agent-governed purchasing workflows where buyer identity, product sensitivity, and approval policy must align before funds are spent — not for general blockchain analytics or wallet monitoring.

## Known failure modes

- Invalid 'to' address format returns a validation error (must match ^0x[a-fA-F0-9]{40}$)
- Invalid or missing 'chain' parameter causes a 400 bad request
- Malformed or oversized calldata (>4096 chars) is rejected
- Missing required query parameters 'chain' or 'to' returns an error
- Unrecognized chain label may result in an unknown network assessment
- Service unavailable on Cloudflare Worker returns 5xx

## How this service works

Machine-payable service intelligence for discovering, verifying, and monitoring identity, risk, authorization, execution-preflight, and evidence APIs before autonomous agents spend.

## Output

Returns a JSON object containing a risk_level (e.g. 'low', 'medium', 'high'), a numeric risk_score, an array of risk flags, plus contextual fields for network, product, identity, activity, and provenance — giving the agent a clear go/no-go signal before signing the payment.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "chain",
      "to"
     ],
     "properties": {
      "to": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]{40}$",
       "description": "Transaction recipient or contract."
      },
      "chain": {
       "type": "string",
       "pattern": "^[A-Za-z0-9:_ -]{2,80}$",
       "description": "Chain or network label for the transaction."
      },
      "calldata": {
       "type": "string",
       "pattern": "^0x[a-fA-F0-9]*$",
       "maxLength": 4096,
       "description": "EVM calldata or 0x for a simple transfer."
      },
      "value_usdc": {
       "type": "string",
       "pattern": "^[0-9]+(?:\\.[0-9]{1,6})?$",
       "description": "Approximate value at risk in USDC."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "network": {
       "type": "string"
      },
      "product": {
       "type": "string"
      },
      "activity": {
       "type": "object"
      },
      "identity": {
       "type": "object"
      },
      "assessment": {
       "type": "object"
      },
      "provenance": {
       "type": "object"
      }
     }
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "network": "eip155:8453",
  "product": "transaction-decode-risk",
  "assessment": {
   "flags": [],
   "risk_level": "low",
   "risk_score": 0
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/signgate-agent-buyer-identity-preflight-transaction-decode-risk-8b47502b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from base-agent-preflight.bytoken2023.workers.dev](https://www.zero.xyz/host/base-agent-preflight.bytoken2023.workers.dev/llms.txt)