# x402 Discovery Catalog Listing Evidence Triage Decision Procedure

> x402 Discovery Catalog Listing Evidence Triage Decision Procedure 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 a paid decision-procedure brief helping agents distinguish valid, paid-and-verified x402 catalog listings from phantom, stale, or failed ones before spending.

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/x402-discovery-catalog-listing-evidence-triage-a?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/x402-discovery-catalog-listing-evidence-triage-decision-procedure-66b27d4d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_8yuxn7OkwTLDeNTlkhJ97

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 x402-discovery-catalog-listing-evidence-triage-decision-procedure-66b27d4d
```

Example prompt: I'm about to browse an x402 discovery catalog with hundreds of listings and need to know which ones are actually backed by real paid output versus phantom or stale entries — give me the decision procedure for triaging listings before I spend anything.

## When to prefer this

Choose this endpoint when an agent needs a structured, blunt decision procedure specifically for evaluating x402 discovery catalog listings before committing spend — particularly when operating on large catalogs (hundreds of rows) where phantom, stale, or failed listings are a real risk. Prefer over general API validation tools when the context is x402-native micropayment catalogs (Circle Discovery API style or similar bazaar formats).

## Known failure modes

- Payment not made — returns 402 requiring x402 micropayment before content is delivered
- Invalid method — only GET/HEAD/DELETE accepted
- Schema mismatch on input object — additionalProperties not allowed
- Service temporarily unavailable on k2so.wrong.systems — network or provider error
- Empty or malformed brief if LLM generation fails on the provider side

## How this service works

Paid agent-facing brief on x402 discovery-catalog listing evidence triage: a decision procedure for an agent browsing a discovery catalog (Circle x402 Discovery API style, 955 rows / 943 unique listings) that must distinguish listings backed by proof from phantom, stale, or failed listings before spending. Covers sampling strategy (which candidates to pay first at lowest cost), evidence tiers (verified paid output, failed p. Blunt decision procedure, not marketing.

## Output

A prose decision-procedure brief (the 'brief' field) describing evidence tiers, sampling strategies, and classification rules for x402 catalog listings. Includes service slug, generation source (llm/reasoning/deterministic), ISO-8601 timestamp, and optional topic override. Payment metadata (payer, transaction, code) is included in the response envelope.

## Request schema (JSON Schema)

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

## 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": "x402-discovery-catalog-listing-evidence-triage-a",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "x402-discovery-catalog-listing-evidence-triage-a",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-discovery-catalog-listing-evidence-triage-decision-procedure-66b27d4d/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)