# K-2SO Agent-Facing Decision Procedure for x402 Endpoints Returning No Payment Terms

> K-2SO Agent-Facing Decision Procedure for x402 Endpoints Returning No Payment Terms is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-16).

Generates a plain-prose decision procedure brief for AI agents on how to handle x402 endpoints that return a paid response without payment terms

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/agent-facing-decision-procedure-for-x402-endpoin
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-16
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/k-2so-agent-facing-decision-procedure-for-x402-endpoints-returning-no-fbd71b47
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0DJROlpwICIzFVZnQRDZH

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-facing-decision-procedure-for-x402-endpoints-returning-no-fbd71b47
```

Example prompt: Give me a decision procedure brief explaining what an autonomous agent should do when it calls an x402 endpoint and gets a paid response that includes no payment terms — use the default GET method.

## When to prefer this

Choose this endpoint when your AI agent needs a structured, LLM-generated decision procedure specifically for navigating x402 endpoints that return paid responses without payment terms — a niche but real edge case in autonomous payment flows. Prefer it over generic documentation lookups when you need actionable prose guidance your agent can directly interpret and act on, and when you are already operating within the x402/Base/USDC payment ecosystem.

## Known failure modes

- Missing or malformed required 'input' object returns a validation error
- Calling with an unsupported HTTP method (POST, PUT, etc.) returns an error
- Payment not settled before retry results in continued 402 response
- Topic override that is too vague may produce a generic or low-utility brief
- Service temporarily unavailable returns a non-200 error with no result payload

## How this service works

Decision procedure for when an x402 endpoint returns no payment terms: no 402 challenge, HTTP 404/405, or a weak merchant contract. Covers probe interpretation, knock-or-backoff thresholds, alternate rail fallback, retry budgets, and kill criteria, ending in a single verdict.

## Output

A JSON response containing a plain-prose decision procedure brief (120+ words) tailored to the topic of x402 endpoints returning paid responses without payment terms, including the generating model, generation source (llm/reasoning/deterministic), ISO-8601 timestamp, and service slug. The 'brief' and 'procedure' fields carry the actionable agent guidance.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "agent-facing decision procedure for x402 endpoints that return no payment terms paid response",
     "$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-facing-decision-procedure-for-x402-endpoints-returning-no-fbd71b47/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)