# 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, $0.02/call, status unknown (last checked 2026-09-15).

Scores an x402 payment counterparty's on-chain settlement behaviour (0-100 risk score) and returns an allow/review/block decision before you pay

## Facts

- Endpoint: POST https://402sentinel.com/api/verify
- Price: $0.02/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-2e9b7a53
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_wDE2EvoxJVlBOo5SyL3fH

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-2e9b7a53 -d '<json body>'
```

Example prompt: Before I pay that x402 API at address 0x6a5e7d954f49712abf3f873f037ec845b7b8c666 on Base for $12 USDC, run a 402Sentinel risk check on it — flag it for review if the score is low or block it if the payment exceeds $50.

## When to prefer this

Use this endpoint when an AI agent is about to make an x402 micropayment and needs an automated pre-payment risk gate — especially when the counterparty address is unknown, the payment amount is non-trivial, or you want a policy-enforceable allow/review/block decision based purely on on-chain settlement behaviour rather than off-chain reputation.

## Known failure modes

- Unknown or brand-new address with no on-chain history — low confidence score returned, decision may be 'review'
- Invalid or malformed payto_address — request rejected with validation error
- Network not supported — error if non-Base network specified and not yet supported
- Insufficient on-chain data to score confidently — confidence below min_confidence threshold triggers conservative block
- Payment for the 402Sentinel call itself fails — no result returned if x402 payment is not fulfilled

## How this service works

Can my x402 service prove it is trustworthy to buyers? 402Sentinel Verified (opt-in trust badge for sellers): deep-audit a service and, if it passes, issue a signed time-boxed 'verified-organic' credential + list it publicly at /api/verified. POST {payto, resource_url?, claimed_buyers?}. Positive-only - failing audits are returned privately, never published.

## Output

A 0-100 risk score derived purely from on-chain settlement behaviour (address age, facilitator-aware payer diversity, settlement maturity) plus a categorical decision of allow, review, or block, optionally conditioned on the requested payment amount and a minimum confidence threshold.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "payto": {
   "type": "string",
   "description": "0x EVM address of the service/seller to deep-audit."
  },
  "resource_url": {
   "type": "string",
   "description": "Optional canonical URL of the service being verified."
  },
  "claimed_buyers": {
   "type": "integer",
   "description": "Optional number of distinct buyers the service claims, to cross-check against the on-chain graph."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/402sentinel-x402-counterparty-risk-gate-2e9b7a53/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)