# Subscription Billing Acceptance Standard for Merchant Agents

> Subscription Billing Acceptance Standard for Merchant Agents is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-10-31).

Returns an accept/conditional/reject decision on a proposed recurring-billing subscription agreement under x402/MPP, checking cancel path, price-change notice windows, and first-charge settlement proof.

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/subscription-billing-acceptance-standard-for-mer?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-10-31
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/subscription-billing-acceptance-standard-for-merchant-agents-b8adbd7a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_2O29rT24coiUIL788mbwU

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 subscription-billing-acceptance-standard-for-merchant-agents-b8adbd7a
```

Example prompt: A merchant just offered me a monthly subscription at a fixed price anchor with a 7-day price-change notice window and an on-rail cancel path — can you run it through the subscription billing acceptance standard to get an accept, conditional, or reject decision before I commit?

## When to prefer this

Choose this endpoint when an autonomous merchant agent needs a deterministic, standards-based gate before accepting a recurring billing arrangement under x402/MPP — particularly when you need structured accept/conditional/reject logic that checks on-rail cancel path availability, price-change notice windows (7-day monthly / 30-day annual), and settled first-charge proof. Prefer this over manual review or generic policy checks when operating unattended and need a reproducible decision trace with prose rationale.

## Known failure modes

- Missing or malformed subscription agreement input yields an error or empty decision
- Unpaid request (no valid x402 payment header) returns a 402 Payment Required response
- Invalid topic override parameter causes fallback to default procedure
- Network or provider-side timeout results in no result object returned
- First-charge settlement proof not verifiable leads to conditional or reject outcome

## How this service works

Deterministic acceptance gate for merchant agents offered recurring billing via x402/MPP. Given a proposed subscription agreement (cadence, price anchor, auto-renew terms, cancel path, refund window), the procedure returns accept / conditional / reject. It requires an on-rail cancel path that the payer can trigger without merchant consent, a fixed billing anchor with a 7-day (monthly) or 30-day (annual) price-change notice window, proof that the first charge actually settled as a normal x402

## Output

A JSON response containing an ok flag, a paid confirmation, and a result object with a boolean success indicator, a plain-prose 'brief' explaining the decision procedure (120+ words), the acceptance outcome (accept/conditional/reject logic embedded in the procedure), an ISO-8601 generatedAt timestamp, the generation source (llm, reasoning, or deterministic), and the service slug and provider (K-2SO).

## Request schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/subscription-billing-acceptance-standard-for-merchant-agents-b8adbd7a/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)