# x402 Refund-Oracle Verification Procedure

> x402 Refund-Oracle Verification Procedure is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-10-21).

Grades merchant refund claims on x402 payment rails by verifying signed attestations and on-chain reversal records before an agent marks a refund as received.

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/x402-refund-oracle-verification-procedure?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-10-21
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-refund-oracle-verification-procedure-121f7644
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_k_C-7jqFAqfRMl4MmLzt8

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-refund-oracle-verification-procedure-121f7644
```

Example prompt: Check whether this merchant refund claim is legit before I mark it as received — verify that the refund attestation is signed by the correct payee key, that the on-rail reversal record sits on the same x402 rail and network as the original payment, and that it landed within 2 settlement cycles.

## When to prefer this

Use this endpoint when an AI agent needs to validate a merchant-issued refund on x402 payment rails before marking the reversal as received or completing reconciliation. Prefer this over generic refund checks when you need x402-specific rule enforcement: payee key signature verification, same-rail reversal confirmation, and settlement-window compliance. Particularly valuable for unattended agents that cannot manually inspect on-chain data.

## Known failure modes

- Attestation not signed by original payee key — claim fails rule 1
- Reversal record on different rail or network than original payment — claim fails rule 2
- Reversal landed outside 2-settlement-cycle window — claim fails rule 2
- Attestation present but no on-rail reversal record found — claim fails rule 3
- Missing or malformed payment ID — unable to look up original payment
- Payment required (402) if not including valid x402 payment header
- Topic override not recognized — falls back to default procedure

## How this service works

Decision procedure that grades merchant refund claims on x402 rails before an agent writes the reversal off as received. Inputs: merchant-signed refund attestation, on-rail reversal record, original payment id and settlement window. Rules: 1) attestation must be signed by the payee key that received the original payment; 2) reversal record must sit on the same rail and network as the original payment and land within 2 settlement cycles; 3) attestation without an on-rail reversal record means

## Output

A JSON object containing an ok boolean, a 'brief' field with plain-prose decision procedure text (120+ words) explaining whether the refund claim passes or fails verification, the topic, service slug, generation source (llm, reasoning, or deterministic), and an ISO-8601 timestamp. The result indicates whether the attestation and reversal record satisfy all three verification rules.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "x402 refund-oracle verification procedure paid response",
     "$schema": "https://json-schema.org/draft/2020-12/schema",
     "required": [
      "ok",
      "paid",
      "service",
      "provider",
      "result"
     ],
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "paid": {
       "type": "boolean"
      },
      "result": {
       "type": "object",
       "required": [
        "ok",
        "service"
       ],
       "properties": {
        "ok": {
         "type": "boolean",
         "description": "Handler success"
        },
        "brief": {
         "type": "string",
         "description": "Decision procedure prose for agents"
        },
        "model": {
         "type": "string"
        },
        "topic": {
         "type": "string"
        },
        "service": {
         "type": "string",
         "description": "Service slug"
        },
        "procedure": {
         "type": "string"
        },
        "generatedAt": {
         "type": "string",
         "description": "ISO-8601 timestamp"
        },
        "generationSource": {
         "enum": [
          "llm",
          "reasoning",
          "deterministic"
         ],
         "type": "string"
        }
       }
      },
      "payment": {
       "type": "object",
       "properties": {
        "code": {
         "type": "string"
        },
        "payer": {
         "type": "string"
        },
        "detail": {
         "type": "string"
        },
 
… (truncated)
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "ok": true,
  "paid": true,
  "result": {
   "ok": true,
   "brief": "plain prose decision procedure (120+ words)",
   "model": "deepseek/deepseek-v4-flash-0731",
   "topic": "string topic",
   "service": "x402-refund-oracle-verification-procedure",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "x402-refund-oracle-verification-procedure",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-refund-oracle-verification-procedure-121f7644/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from k2so.wrong.systems](https://www.zero.xyz/host/k2so.wrong.systems/llms.txt)