# x402 Evidence Crosscheck

> x402 Evidence Crosscheck is a paid API for AI agents from agente.revenuerecoveryai.app, paid per call via x402, $0.01/call, status unknown (last checked 2026-10-01).

Independently verifies an x402 payment endpoint by comparing what a seller declares (price, payTo, network, method) against what a live observer sees right now, returning field-level discrepancy evidence with classification and a signed receipt.

## Facts

- Endpoint: GET https://agente.revenuerecoveryai.app/v1/x402/evidence-crosscheck?utm_source=zero.xyz
- Price: $0.01/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-01
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-evidence-crosscheck-299786f5
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_sHRAOwe6RSkdJe7fz_jZG

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 x402-evidence-crosscheck-299786f5
```

Example prompt: Can you do a live crosscheck on https://api.example.com/premium-data to see if its x402 price, payTo address, and network match what's listed in the Bazaar catalogue — and tell me if any differences are protocol-legal or actual drift?

## When to prefer this

Use this endpoint when you need an independent, third-party audit of a specific x402 resource before paying or routing traffic through it, or when you suspect the declared payment parameters (price, payTo, network, method) may have drifted from what's actually live. Prefer this over purely trusting the seller's own manifest or Bazaar listing. It is especially valuable when distinguishing protocol-legal dynamic price changes from unauthorized tampering or misconfiguration. For auditing up to 25 endpoints at once, prefer the batch variant.

## Known failure modes

- Target URL is not reachable or returns non-x402 response — evidence returned as 'unavailable' for live fields
- Target URL uses unsupported HTTP method — 400 error; only GET, HEAD, DELETE are supported
- No Bazaar catalogue entry found for the target — comparison is partial, only manifest vs live
- Network timeout on live probe — timestamp recorded but live evidence fields marked as failed
- Malformed target_url parameter — validation error returned before any probe is attempted

## How this service works

Independent second opinion on an x402 resource: compares the seller's Bazaar listing and x402 manifest against the live observed price, payTo, network, method and paywall. Field-level evidence with source, timestamp and hash, plus a signed receipt. / Segunda opinión independiente sobre un recurso x402: compara la ficha pública del Bazaar y el manifiesto x402 del vendedor con el precio, destino, red, método y muro de pago observados en vivo. Evidencia por campo con fuente y recibo firmado.

## Output

Returns field-level evidence for each checked attribute (price, payTo address, network, HTTP method, paywall presence), each with its source, timestamp, and hash. Discrepancies are classified as protocol-legal dynamic behavior or real drift. A signed receipt is included for auditability.

## 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",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "target_url"
     ],
     "properties": {
      "target_url": {
       "type": "string",
       "description": "HTTPS URL of the x402 resource to check."
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "target": "https://api.example.com/v1/resource",
  "receipt": {
   "alg": "Ed25519",
   "key_id": "k1",
   "signature": "..."
  },
  "summary": {
   "status": "WARN",
   "actionable": 1,
   "differences": 1,
   "expected_behavior": 0
  },
  "declared": {
   "amount": "10000",
   "method": "GET",
   "pay_to": "0xabc...",
   "source": "bazaar",
   "network": "eip155:8453"
  },
  "observed": {
   "price": {
    "value": "10000",
    "source": "live_402_header",
    "confidence": "HIGH",
    "observed_at": "2026-08-10T14:03:11+00:00",
    "observations": 3,
    "evidence_hash": "sha256:7b21..."
   },
   "payable": {
    "value": "LIVE_PAYABLE",
    "source": "live_probe",
    "confidence": "HIGH",
    "observed_at": "2026-08-10T14:03:11+00:00",
    "observations": 3,
    "evidence_hash": "sha256:1f0c..."
   }
  },
  "surfaces": {
   "bazaar": {
    "present": true
   },
   "openapi": {
    "present": false
   },
   "live_402": {
    "probed": true,
    "post_policy": null,
    "observations": 3,
    "probed_method": "GET",
    "declared_method": "GET"
   },
   "well_known": {
    "present": true
   },
   "method_bypass": {
    "note": "the alternate method would be POST, which is never sent to a target solely to test for a bypass",
    "method": "POST",
    "probed": false
   }
  },
  "payability": {
   "live": "LIVE_PAYABLE",
   "note": "we never pay the target by design: post-payment delivery is not observable from here and is never inferred",
   "delivery_verified": "UNAVAILABLE_BY_DESIGN"
  },
  "differences": [
   {
    "field": "price",
    "reason": "the amount was stable across 3 observations and differs from the declared one (1.20x)",
    "rule_id": "XCC-010",
    "declared": "10000",
    "observed": "12000",
    "severity": "warning",
    "confidence": "HIGH",
    "evidence_refs": [
     "hash:sha256:7b21..."
    ],
    "classification": "STALE_CATALOG_PRICE"
   }
  ],
  "duration_ms": 2410,
  "observed_at": "2026-08-10T14:03:11+00:00",
  "rules_version": "2026.08.09.1",
  "schema_version": "1.0.0"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-evidence-crosscheck-299786f5/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agente.revenuerecoveryai.app](https://www.zero.xyz/host/agente.revenuerecoveryai.app/llms.txt)