# K-2SO Agent Decision Procedure for x402 Merchant Endpoints

> K-2SO Agent Decision Procedure for x402 Merchant Endpoints is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-09-15).

Generates a plain-prose decision procedure brief for AI agents on how to handle x402 merchant endpoints that return 402 Payment Required responses

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/agent-decision-procedure-for-x402-merchant-endpo
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/k-2so-agent-decision-procedure-for-x402-merchant-endpoints-0774d808
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Ip1Xx0VkCkiUIVBtmqt7k

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 k-2so-agent-decision-procedure-for-x402-merchant-endpoints-0774d808
```

Example prompt: Give me the decision procedure an autonomous agent should follow when it hits a 402 Payment Required from an x402 merchant endpoint — I need the full plain-prose brief on how to settle USDC and retry.

## When to prefer this

Choose this endpoint when an autonomous agent needs actionable, LLM-generated prose guidance specifically for navigating x402 payment-gated APIs on Base — particularly the pay-and-retry cycle using USDC. Prefer this over static documentation when the agent needs dynamically generated, topic-specific decision logic it can interpret and act on at runtime.

## Known failure modes

- Missing or invalid payment signature results in continued 402 response
- Network or RPC failure on Base when settling USDC returns a timeout or 5xx
- Malformed topic override parameter returns an error or falls back to default topic
- Free metadata request (meta=1) returns schema info without the decision procedure brief

## How this service works

Paid agent-facing brief on agent decision procedure for x402 merchant endpoints that fail to quote: HTTP 404/405/no-402-challenge handling, knock-or-backoff, retry policy, alternative merchant fallback, contract quality scoring-0. Blunt decision procedure, not marketing.

## Output

A JSON object containing a plain-prose decision procedure brief (120+ words) explaining exactly what an autonomous agent should do when it encounters a 402 Payment Required from an x402 merchant endpoint, along with the topic slug, model used to generate it, generation source (llm, reasoning, or deterministic), ISO-8601 timestamp, and provider identifier (K-2SO).

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "agent decision procedure for x402 merchant endpoints that fail to quot paid response",
     "$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": {
         
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/k-2so-agent-decision-procedure-for-x402-merchant-endpoints-0774d808/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)