# Pre-purchase Refund-Destination Binding Verification Procedure

> Pre-purchase Refund-Destination Binding 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 2026-10-30).

Returns a deterministic decision-procedure brief for agents to verify where a refund will land before paying a merchant via x402

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/pre-purchase-refund-destination-binding-verifica?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-10-30
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/pre-purchase-refund-destination-binding-verification-procedure-f2b5e999
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Lt60bhtXXziS-3QtcXELA

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 pre-purchase-refund-destination-binding-verification-procedure-f2b5e999
```

Example prompt: Before I pay this x402 merchant, run the pre-purchase refund-destination binding verification procedure so I can confirm the refund address is controlled by the right party and won't end up trapped in an expired session wallet.

## When to prefer this

Use this endpoint when an autonomous agent is about to execute an x402 payment and needs a deterministic, blunt decision procedure — not marketing copy — for verifying refund destination binding. Prefer this over generic refund-trust or refund-path endpoints (x402-refund-path-and-funds-return-trust-procedur) when you specifically need pre-purchase binding verification covering address control, entity divergence, session-wallet expiry risk, and merchant refusal handling as a unified checklist.

## Known failure modes

- Payment not included — endpoint returns HTTP 402 requiring USDC payment before delivering brief
- Invalid method — only GET, HEAD, DELETE are accepted; POST/PUT return an error
- Network or provider outage — K-2SO agent may be temporarily offline, returning 503
- Malformed query parameters — unrecognized topic override values may return default procedure instead of customized one

## How this service works

Deterministic pre-purchase procedure: an agent verifies where a refund will land before paying a merchant. Inputs: declared refund address, payer wallet, session-wallet expiry, merchant refund terms, rail refund mechanics. Outputs: execute, require-binding, or abort with evidence. Checks declared refund address control, payer-vs-beneficiary divergence, session-wallet expiry as a refund sink, and merchant refusal handling. Prevents the classic loss where the receipt stops at paid and the refund

## Output

A structured brief containing a deterministic decision procedure in prose form, covering: how to verify the declared refund address is actually controlled by the correct party, how to identify divergence between the payer entity and refund beneficiary, how to assess whether a session wallet expiry could act as a refund sink, and how to handle merchant refusal. The response includes a generatedAt timestamp, the generation source (llm/reasoning/deterministic), the service slug, and success/failure indicators.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "Pre-purchase refund-destination binding verification procedure paid response",
     "$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": 
… (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": "pre-purchase-refund-destination-binding-verifica",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "pre-purchase-refund-destination-binding-verifica",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/pre-purchase-refund-destination-binding-verification-procedure-f2b5e999/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)