Market Data · x402 · early usage

Deterministically score a task brief for deliverables, acceptance criteria, deadlines,…

Deterministically score a task brief for deliverables, acceptance criteria, deadlines, constraints, and usable scope before committing time. No AI calls; same brief always yields the same score.

by keystone-opportunity-api.keystone-opportunity.workers.dev · discovered, not yet claimed by its owner · updated 2026-10-11

30d calls3

30d payers3

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

Deterministically score a task brief for deliverables, acceptance criteria, deadlines, constraints, and usable scope before committing time. No AI calls; same brief always yields the same score.

Tags: agents · brief · validation · qa · tasks · bazaar

Call contract

Method: POST
Input: json
Output: json
Last paid call: 2026-10-11

Input example from Bazaar metadata

{
  "brief": "Deliverable: submit report.md within 24 hours. Acceptance: include three cited findings. Constraints: no confidential data."
}

Output example

{
  "characters": 121,
  "checks": [
    {
      "id": "deliverable",
      "message": "Name the exact file, artifact, or outcome to deliver.",
      "passed": true
    }
  ],
  "ready": false,
  "score": 80
}

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/29392.json for the price and payment options.
Pay. Call GET https://keystone-opportunity-api.keystone-opportunity.workers.dev/v1/brief-check. 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: $0.001 / request
Protocol: x402 v2
Auth: No account or API key. Pay per request.
Networks: Base
Demand: 3 calls · 3 unique payers in 30d (public x402 Bazaar data)

x402 payment requirements

Scheme	Network	Asset	Amount	Pay to	Timeout
exact	Base eip155:8453	USDC	$0.001	0xD3faD775704a0Ed209315A406c3D99ED589ee723	300s

accepts[] (raw JSON)

[
  {
    "scheme": "exact",
    "network": "eip155:8453",
    "payTo": "0xD3faD775704a0Ed209315A406c3D99ED589ee723",
    "asset": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
    "amount": "1000",
    "amountUsd": 0.001,
    "maxTimeoutSeconds": 300
  }
]

Schemas

Output schema (JSON Schema)

{
  "properties": {
    "example": {
      "type": "object"
    },
    "type": {
      "type": "string"
    }
  },
  "required": [
    "type"
  ],
  "type": "object"
}

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

{
  "example": {},
  "type": "string"
}

Examples

curl

curl -X POST 'https://keystone-opportunity-api.keystone-opportunity.workers.dev/v1/brief-check' -H 'Content-Type: application/json' --data '{"brief":"Deliverable: submit report.md within 24 hours. Acceptance: include three cited findings. Constraints: no confidential data."}'
# -> 402 Payment Required; read PAYMENT-REQUIRED
# retry the identical request with PAYMENT-SIGNATURE

JavaScript

const res = await fetch("https://keystone-opportunity-api.keystone-opportunity.workers.dev/v1/brief-check", {
  "method": "POST",
  "headers": {
    "content-type": "application/json"
  },
  "body": "{\"brief\":\"Deliverable: submit report.md within 24 hours. Acceptance: include three cited findings. Constraints: no confidential data.\"}"
});
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
import json
res = httpx.request("POST", "https://keystone-opportunity-api.keystone-opportunity.workers.dev/v1/brief-check", json=json.loads("{\"brief\":\"Deliverable: submit report.md within 24 hours. Acceptance: include three cited findings. Constraints: no confidential data.\"}"))
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: keystone-opportunity-api.keystone-opportunity.workers.dev
Endpoint: https://keystone-opportunity-api.keystone-opportunity.workers.dev/v1/brief-check
Machine-readable: /resources/29392.json