# x402 Discovery Price Compare Tool

> x402 Discovery Price Compare Tool is a paid API for AI agents from gpt55.558686.xyz, paid per call via x402, $0.003/call, status unknown (last checked 2026-09-15).

Fetches and compares x402 API pricing and discovery metadata across multiple URLs or origins in a single structured call.

## Facts

- Endpoint: GET https://gpt55.558686.xyz/v1/tools/x402-discovery-price-compare
- Price: $0.003/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/x402-discovery-price-compare-tool-eae8acac
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_D-KSN_2ziF4egmyTfM-4M

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-price-compare-tool-eae8acac
```

Example prompt: Compare x402 pricing across these three API discovery URLs for me: https://api1.example.com, https://api2.example.com, and https://api3.example.com — return a structured price comparison so I can pick the cheapest one.

## When to prefer this

Use this endpoint when you need to compare x402 payment pricing across multiple API endpoints or origins in one call. Prefer it over manual per-endpoint fetches when you have 2–10 candidate x402 APIs and want a unified structured price comparison without subscribing to a service.

## Known failure modes

- No urls/origins/discovery_urls provided — returns validation error
- Timeout exceeded for slow remote endpoints — partial or error response
- Invalid URL format in input list — schema validation failure
- Remote x402 endpoint returns non-standard response — parsing failure
- Exceeds 10 URL limit — request rejected

## How this service works

Fetch up to 10 x402 discovery documents or service origins, extract paid resources, normalize USDC atomic amounts, and rank resources by price, scheme, network, tags, and service metadata. This deterministic endpoint does not call an upstream model. GET variant for agents, crawlers, and wallets that prefer query parameters over a JSON body. Pay up to $0.003 per request with x402 USDC on Base.

## Output

A structured JSON object with ok status, tool name 'x402DiscoveryPriceCompare', a summary string describing the price comparison results, and a fetchedAt timestamp. Includes aggregated pricing metadata from the queried URLs or origins.

## 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"
    },
    "pathParams": {
     "type": "object",
     "additionalProperties": true
    },
    "queryParams": {
     "type": "object",
     "anyOf": [
      {
       "required": [
        "urls"
       ]
      },
      {
       "required": [
        "origins"
       ]
      },
      {
       "required": [
        "discovery_urls"
       ]
      }
     ],
     "properties": {
      "urls": {
       "type": "array",
       "items": {
        "type": "string",
        "maxLength": 2048,
        "minLength": 1
       },
       "maxItems": 10,
       "minItems": 1
      },
      "limit": {
       "type": "integer",
       "maximum": 100,
       "minimum": 1
      },
      "query": {
       "type": "string",
       "maxLength": 120
      },
      "origins": {
       "type": "array",
       "items": {
        "type": "string",
        "maxLength": 2048,
        "minLength": 1
       },
       "maxItems": 10,
       "minItems": 1
      },
      "max_bytes": {
       "type": "integer",
       "maximum": 1048576,
       "minimum": 4096
      },
      "timeout_ms": {
       "type": "integer",
       "maximum": 12000,
       "minimum": 1000
      },
      "discovery_urls": {
       "type": "array",
       "items": {
        "type": "string",
        "maxLength": 2048,
        "minLength": 1
       },
       "maxItems": 10,
       "minItems": 1
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "ok": {
       "type": "boolean"
      },
      "tool": {
       "type": "string"
      },
      "fetchedAt": {
       "type": "string"
      }
     },
     "additionalProperties": true
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402-discovery-price-compare-tool-eae8acac/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from gpt55.558686.xyz](https://www.zero.xyz/host/gpt55.558686.xyz/llms.txt)