# Live Advertised-vs-Billed Price Divergence Index for x402 Merchants

> Live Advertised-vs-Billed Price Divergence Index for x402 Merchants is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-10-19).

Returns a live price-honesty index showing whether x402 merchants bill a different amount than they advertised in their HTTP 402 challenge, including a divergence ratio, severity classification, and pay/skip verdict.

## Facts

- Endpoint: GET https://k2so.wrong.systems/api/services/live-advertised-vs-billed-price-divergence-index?utm_source=zero.xyz
- Price: $0.002/call
- Payment: x402
- Status: down
- Last checked: 2026-10-19
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/live-advertised-vs-billed-price-divergence-index-for-x402-merchants-c12e0a23
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7GPNlxJfhepMqZoygNVlw

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 live-advertised-vs-billed-price-divergence-index-for-x402-merchants-c12e0a23
```

Example prompt: Before I pay this x402 merchant, check if there's a price divergence — they advertised 0.001 USDC in the 402 challenge but billed 0.01 USDC after settlement. The merchant ID is meme-generator-001. Is this a hard flag or should I skip payment?

## When to prefer this

Use this endpoint when an AI agent needs to verify price integrity for a specific x402 merchant before or after settlement — especially when the challenge price differs from the settlement amount. Prefer this over generic merchant lookup services when you need x402-specific severity classification (soft/hard/no-pay thresholds) and an actionable pay/skip verdict grounded in observed billing clusters from 2026.

## Known failure modes

- Missing or invalid merchant ID returns an error or empty result
- If challenge price or billed amount is not provided, the procedure may fall back to topic-level heuristics only
- LLM-generated briefs may vary in wording but deterministic severity classes remain stable
- Unknown merchants with no observed billing history may return inconclusive verdicts
- Rate limiting or payment verification failure may block the paid response

## How this service works

Live price-honesty index: which x402 merchants advertise one price in the 402 challenge and bill a different amount after settlement. Agent input: challenge price, billed amount, merchant id. Output: divergence ratio, severity class (soft flag >= 1.5x, hard flag >= 3x, no-pay >= 10x), pay/skip verdict, evidence row. Includes the observed 2026-08 cluster: Meme Generator, Useless Fact, Coin Flip, Riddle Oracle advertising 0.001 to 0.002 but billing 0.01, and onesource.io block-number billing 2x

## Output

A JSON object containing a divergence ratio (billed/advertised), a severity class label (none, soft-flag ≥1.5x, hard-flag ≥3x, or no-pay ≥10x), a pay/skip verdict for the agent, an evidence row with transaction details, and a plain-prose decision procedure (brief) explaining the reasoning — all generated deterministically or via LLM reasoning and timestamped.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET",
      "HEAD",
      "DELETE"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "properties": {
      "meta": {
       "enum": [
        "0",
        "1"
       ],
       "type": "string",
       "description": "Set to 1 for free metadata JSON (no payment required)"
      },
      "topic": {
       "type": "string",
       "description": "Optional topic override for the decision procedure"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "title": "live advertised-vs-billed price divergence index for x402 merchants paid response",
     "$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": {
         "ty
… (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": "live-advertised-vs-billed-price-divergence-index",
   "procedure": "same as brief",
   "generatedAt": "2026-01-01T00:00:00.000Z",
   "generationSource": "deterministic"
  },
  "service": "live-advertised-vs-billed-price-divergence-index",
  "provider": "K-2SO"
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/live-advertised-vs-billed-price-divergence-index-for-x402-merchants-c12e0a23/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)