# 402Sentinel x402 Counterparty Risk Gate

> 402Sentinel x402 Counterparty Risk Gate is a paid API for AI agents from 402sentinel.com, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-15).

Scores an x402 payment counterparty address 0-100 for risk and returns an allow/review/block decision based on on-chain settlement behaviour before you pay

## Facts

- Endpoint: POST https://402sentinel.com/api/policy
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/402sentinel-x402-counterparty-risk-gate-2c9c20e6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4o1ULJTYuchWWEKyJMCpC

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 402sentinel-x402-counterparty-risk-gate-2c9c20e6 -d '<json body>'
```

Example prompt: Before I pay that x402 endpoint at address 0xAbC123..., run it through 402Sentinel and tell me its risk score and whether I should allow, review, or block the payment.

## When to prefer this

Use this endpoint when your AI agent is about to make an x402 pay-per-call payment and needs a pre-payment counterparty risk check based purely on on-chain settlement behaviour. Prefer this over generic blockchain analytics tools when the specific concern is x402 protocol counterparty trust and facilitator-aware risk scoring on Base.

## Known failure modes

- Unknown or brand-new address with no on-chain history may return low-confidence score
- Invalid or malformed address input returns validation error
- Address not on Base network may be unsupported
- x402 payment for the API call itself fails if caller wallet has insufficient USDC
- Rate limiting or service unavailability returns 5xx error

## How this service works

Same input as /api/assess, but returns a trimmed action-oriented view: the allow/limit/deny decision plus a wallet-ready spending policy (max_payment_usdc per-counterparty cap, daily_cap_usdc, add_to_denylist, require_human_approval) an agent can apply directly to its wallet limits.

## Output

Returns a 0-100 risk score and a categorical decision (allow, review, or block) for the queried counterparty address, derived from on-chain signals including address age, payer diversity, facilitator awareness, and settlement maturity on Base.

## Example request

```json
{
 "policy": {
  "min_confidence": 0.5,
  "max_payment_usdc": 50,
  "review_ceiling_usdc": 5
 },
 "target": {
  "payto_address": "0x6a5e7d954f49712abf3f873f037ec845b7b8c666"
 },
 "payment_context": {
  "asset": "USDC",
  "amount": 10
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "policy": {
   "type": "object",
   "properties": {
    "min_confidence": {
     "type": "number"
    },
    "max_payment_usdc": {
     "type": "number"
    },
    "review_ceiling_usdc": {
     "type": "number"
    }
   },
   "description": "Optional caller thresholds shaping the returned spending policy."
  },
  "target": {
   "type": "object",
   "required": [
    "payto_address"
   ],
   "properties": {
    "payto_address": {
     "type": "string",
     "description": "Address that receives the payment — 0x EVM (Base) OR base58 Solana."
    }
   },
   "description": "The x402 seller to score."
  },
  "payment_context": {
   "type": "object",
   "properties": {
    "asset": {
     "type": "string",
     "description": "e.g. \"USDC\""
    },
    "amount": {
     "type": "number"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/402sentinel-x402-counterparty-risk-gate-2c9c20e6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 402sentinel.com](https://www.zero.xyz/host/402sentinel.com/llms.txt)