Payments · x402 · early usage

For supplied field names, distinguish absent keys, explicit nulls, blank strings and po…

For supplied field names, distinguish absent keys, explicit nulls, blank strings and populated values across JSON records.

by penny-army-reference-mainnet.spruceboundgranitestudio.workers.dev · discovered, not yet claimed by its owner · updated 2026-09-30

30d calls1

30d payers1

MethodPOST

Outputjson

Mirrored from Coinbase's public x402 Bazaar. The description is the provider's own text and has not been reviewed here; the payment requirements are copied as published.

What it does

For supplied field names, distinguish absent keys, explicit nulls, blank strings and populated values across JSON records.

Tags: quality · column-completeness · bazaar · payment-identifier

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-09-30

Input example from Bazaar metadata

{
  "fields": [
    "sku",
    "title",
    "price"
  ],
  "rows": [
    {
      "price": 0,
      "sku": "A-100",
      "title": "Desk"
    },
    {
      "price": null,
      "sku": "A-101",
      "title": " "
    },
    {
      "sku": "A-102"
    },
    {
      "price": 19.5,
      "sku": "A-103",
      "title": "Lamp"
    }
  ]
}

Output example

{
  "result": {
    "columns": [
      {
        "absent": 0,
        "blanks": 0,
        "field": "sku",
        "nulls": 0,
        "populated": 4
      },
      {
        "absent": 1,
        "blanks": 1,
        "field": "title",
        "nulls": 0,
        "populated": 2
      },
      {
        "absent": 1,
        "blanks": 0,
        "field": "price",
        "nulls": 1,
        "populated": 2
      }
    ],
    "rows": 4
  },
  "schema_version": "research-1",
  "test_only": false,
  "utility_id": "column-completeness"
}

Use with an agent

Discover. Agents find this listing with GET https://bazaar.saylorinnovations.com/discovery/search?query=…, the MCP tool search_resources, or /discovery/resources.
Inspect. Fetch /resources/37842.json for the price and payment options.
Pay. Call GET https://penny-army-reference-mainnet.spruceboundgranitestudio.workers.dev/v1/probes/column-completeness. The provider answers 402 with its payment requirements. An x402 client signs one of the options below and retries with PAYMENT-SIGNATURE.
Execute. The provider returns 200 with the data. Agent Bazaar is not in the request path and never sees your payment.

For humans

You don't need an account or an API key; you need a wallet holding a small amount of USDC on Base, and an x402-capable client (see the examples below). Call the endpoint unpaid first to see exactly what it asks for.

Pricing & payment

Price: $0.05 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Demand: 1 calls · 1 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.05	0xce53bde2C7a639fc5526AC006a8A7866625d1342	60s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xce53bde2C7a639fc5526AC006a8A7866625d1342",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "50000",
    "amountUsd": 0.05,
    "maxTimeoutSeconds": 60
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "$schema": "https://json-schema.org/draft/2020-12/schema",
      "additionalProperties": false,
      "description": "Deterministic counts of own top-level keys. Blank means a string whose trim() is empty. Zero, false, empty arrays and empty objects are populated. Duplicate field names are counted once in first-occurrence order. At most 128 rows and 64 field names, subject to shared byte/complexity limits. No nested-path, type, schema, factual or source validation. Same valid input and implementation version produce the same result; this is not an external correctness certification. No upstream API or model call. Results may contain supplied fields and are retained in the shared result store. Do not submit secrets or private data. Recovery expires 24 hours after claim; physical deletion/backups follow existing environment policy.",
      "properties": {
        "result": {
          "additionalProperties": false,
          "properties": {
            "columns": {
              "items": {
                "additionalProperties": false,
                "properties": {
                  "absent": {
                    "maximum": 9007199254740991,
                    "minimum": -9007199254740991,
                    "type": "integer"
                  },
                  "blanks": {
                    "maximum": 9007199254740991,
                    "minimum": -9007199254740991,
                    "type": "integer"
                  },
                  "field": {
                    "type": "string"
                  },
                  "nulls": {
                    "maximum": 9007199254740991,
                    "minimum": -9007199254740991,
                    "type": "integer"
                  },
                  "populated": {
                    "maximum": 9007199254740991,
                    "minimum": -9007199254740991,
                    "type": "integer"
                  }
                },
                "required": [
                  "field",
                  "absent",
                  "nulls",
                  "blanks",
                  "populated"
                ],
                "type": "object"
              },
              "type": "array"
            },
            "rows": {
              "maximum": 9007199254740991,
              "minimum": -9007199254740991,
              "type": "integer"
            }
          },
          "required": [
            "rows",
            "columns"
          ],
          "type": "object"
        },
        "schema_version": {
          "const": "research-1",
          "type": "string"
        },
        "test_only": {
          "const": false,
          "type": "boolean"
        },
        "utility_id": {
          "const": "column-completeness",
          "type": "string"
        }
      },
      "required": [
        "schema_version",
        "utility_id",
        "test_only",
        "result"
      ],
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

Example shape — generated from the schema, not a captured live response

{
  "example": {
    "result": {
      "columns": [
        {
          "absent": 0,
          "blanks": 0,
          "field": "string",
          "nulls": 0,
          "populated": 0
        }
      ],
      "rows": 0
    },
    "schema_version": "string",
    "test_only": true,
    "utility_id": "string"
  },
  "type": "string"
}

Examples

curl

curl "https://penny-army-reference-mainnet.spruceboundgranitestudio.workers.dev/v1/probes/column-completeness"
# -> 402 Payment Required, accepts[] lists how to pay
# retry with a PAYMENT-SIGNATURE (or PAYMENT header) once paid

JavaScript

const res = await fetch("https://penny-army-reference-mainnet.spruceboundgranitestudio.workers.dev/v1/probes/column-completeness");
if (res.status === 402) {
  const { accepts } = await res.json();
  // pay one of accepts[] via an x402 client, then retry with the payment header
}

Python

import httpx
res = httpx.get("https://penny-army-reference-mainnet.spruceboundgranitestudio.workers.dev/v1/probes/column-completeness")
if res.status_code == 402:
    accepts = res.json()["accepts"]
    # pay one of accepts[] via an x402 client, then retry with the payment header

Details

Provider: penny-army-reference-mainnet.spruceboundgranitestudio.workers.dev
Endpoint: https://penny-army-reference-mainnet.spruceboundgranitestudio.workers.dev/v1/probes/column-completeness
Machine-readable: /resources/37842.json