# 402Sentinel Counterparty Risk Assessment

> 402Sentinel Counterparty Risk Assessment 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 0-100 for risk and returns an allow/review/block decision based purely on on-chain settlement behavior before you pay.

## Facts

- Endpoint: POST https://402sentinel.com/api/assess
- 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-counterparty-risk-assessment-99c4219f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fPGxy-INCD30KlSnl0Rr7

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-counterparty-risk-assessment-99c4219f -d '<json body>'
```

Example prompt: Before I pay this x402 API, run a 402Sentinel risk check on the counterparty address 0xAbC123... and tell me the risk score and whether I should allow, review, or block the payment.

## When to prefer this

Use 402Sentinel when your AI agent is about to make an x402 micropayment on Base and you want to gate the transaction on counterparty risk before committing funds — especially when dealing with unknown or newly encountered x402 endpoints. It is distinct from generic wallet screening tools because it uses facilitator-aware, x402-specific on-chain settlement signals rather than sanctions lists or token-transfer heuristics.

## Known failure modes

- Address has no on-chain settlement history — score may default to high-risk or review
- Invalid or malformed address input returns an error
- Address on an unsupported network (not Base) may return incomplete data
- Service unavailable if x402 payment for the call itself fails
- Rate limiting if payment is not processed correctly

## How this service works

Assess an x402 counterparty before paying. POST {target:{payto_address}, payment_context?, policy?}; payto may be a 0x EVM (Base) or base58 Solana seller. Returns risk_score 0-100, decision allow/review/block, confidence, coverage, per-dimension signals, key_factors (what drove the score) and a ready-to-apply recommended_policy. Scored from on-chain settlement behaviour, OFAC sanctions = hard block.

## Output

Returns a 0-100 risk score and an allow/review/block decision derived from on-chain signals including address age, facilitator-aware payer diversity, and settlement maturity for the queried counterparty address.

## 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",
   "description": "Optional caller policy hints."
  },
  "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"
    }
   },
   "description": "Optional context about the payment being considered."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/402sentinel-counterparty-risk-assessment-99c4219f/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)