# Merchant Delivery Receipt Issuance Standard

> Merchant Delivery Receipt Issuance Standard is a paid API for AI agents from k2so-8080.on.ascii.dev, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-15).

Returns a decision procedure for x402 merchants on how to issue verifiable proof-of-delivery receipts after an agent pays for data, compute, or a service.

## Facts

- Endpoint: GET https://k2so-8080.on.ascii.dev/api/services/merchant-delivery-receipt-issuance-standard
- 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/merchant-delivery-receipt-issuance-standard-75430310
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_knAoQHF3gt2-z0dhqg02I

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 merchant-delivery-receipt-issuance-standard-75430310
```

Example prompt: I'm building an x402 merchant service and need to know the correct procedure for issuing verifiable proof-of-delivery receipts — including what schema to use, when to issue them, how to handle partial fulfillment, and how to respond to buyer disputes.

## When to prefer this

Choose this endpoint when you are an x402 merchant or merchant-side agent developer who needs authoritative, structured guidance on issuing delivery receipts — particularly when you need to cover receipt schema design, evidence binding, partial fulfillment edge cases, and dispute responses in a single lookup. Prefer this over generic payment documentation when you specifically need the buyer-verifiable proof-of-delivery layer of x402 compliance.

## Known failure modes

- Payment not included — returns 402 requiring USDC payment before content is served
- Invalid HTTP method — only GET/HEAD/DELETE accepted per schema enum
- Malformed query parameters — topic or meta values outside allowed types return validation errors
- LLM generation failure — generationSource may fall back or result field may lack 'brief' prose
- Service temporarily unavailable — upstream K-2SO reasoning service may be down

## How this service works

Decision procedure for x402 merchants issuing verifiable proof-of-delivery receipts when an agent pays for data, compute, or a service. Covers receipt schema, delivery evidence binding, issuance timing, partial fulfillment handling, and dispute response so buyer agents can prove the merchant actually delivered.

## Output

A structured decision procedure in prose form (the 'brief' field) covering: receipt schema definition, how to bind delivery evidence to receipts, correct issuance timing, how to handle partial fulfillment scenarios, and how to formulate dispute responses — returned alongside metadata like generation source, timestamp, model used, and service slug.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "Merchant delivery receipt issuance standard paid response",
     "$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)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/merchant-delivery-receipt-issuance-standard-75430310/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from k2so-8080.on.ascii.dev](https://www.zero.xyz/host/k2so-8080.on.ascii.dev/llms.txt)