# K-2SO Agent-Facing Decision Procedure for Choosing x402/Agent-Service

> K-2SO Agent-Facing Decision Procedure for Choosing x402/Agent-Service is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-09-13).

Generates a plain-prose decision procedure that guides an AI agent in selecting which x402 or agent-service paid API to call for a given task

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/agent-facing-decision-procedure-for-choosing-whi
- Price: $0.002/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/k-2so-agent-facing-decision-procedure-for-choosing-x402-agent-service-15a740f1
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NU9w_yl3dKEnFA992PW4O

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-choosing-x402-agent-service-15a740f1
```

Example prompt: Can you generate a decision procedure in plain prose that tells my AI agent how to choose which x402 paid service to call when it needs to run a market scan — use the topic 'market scan service selection'?

## When to prefer this

Choose this endpoint when an AI agent needs structured, prose-form guidance on how to evaluate and select among x402 paid APIs — particularly when the agent operates autonomously in the Base/USDC micropayment ecosystem and needs a portable, model-readable decision procedure rather than hard-coded routing logic. Prefer this over generic LLM prompting when you want a vendor-specific, x402-aware procedure with payment provenance attached.

## Known failure modes

- HTTP 402 returned if USDC payment is not settled before retry — agent must complete x402 payment flow first
- Invalid or missing 'input' object causes schema validation failure
- Topic override ignored if malformed or too long
- LLM generation may fall back to deterministic source if model unavailable
- Payment signature mismatch results in 402 rejection without service delivery

## How this service works

Paid agent-facing brief: a fixed-priority decision procedure for choosing among x402 discovery catalogs (Circle, Coinbase Bazaar, PayAI, mpp.dev) by service need type. Includes required inputs, no-pay rule for discovery queries, and pay threshold for selected service. Blunt, non-marketing, for autonomous agents.

## Output

A JSON object containing a plain-prose decision procedure (120+ words) under 'brief'/'procedure', the LLM model used, the topic, the service slug, an ISO-8601 generation timestamp, the generation source (llm/reasoning/deterministic), and top-level ok/paid/provider fields confirming successful settlement.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "Agent-facing decision procedure for choosing which x402/agent-service paid response",
     "$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-choosing-x402-agent-service-15a740f1/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)