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Keystone Opportunity API – Brief Check
x402
Keystone Opportunity API – Brief Check is a paid API for AI agents from keystone-opportunity-api.keystone-opportunity.workers.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-14).
Validates a task brief for autonomous agents, scoring it for completeness and readiness before execution
Price / call$0.001
Success—
StatusUnknown
How this service works
Low-cost, deterministic x402 utilities for autonomous agents on Base. Every /v1 route is priced in USDC and settles onchain via the x402 protocol; discover and pay programmatically through the x402 Bazaar. No API keys, no subscriptions.
Output
Returns a JSON object with a boolean 'ready' flag, an integer 'score' (0-100), an array of 'checks' each with an id, passed status, and descriptive message, and a 'characters' count of the brief. Agents can use the score and failed checks to iteratively improve the brief before execution.
Example use cases
Pre-flight check before agent execution
“I want to make sure my brief is solid before my agent starts working on it — can you validate this: 'Scrape the top 10 products from example.com/shop and export the names, prices, and URLs as a CSV file named products.csv'?”
Debugging a low-quality task spec
“My agent keeps failing on this task and I think the brief might be the problem. Can you score this brief and tell me what's wrong with it: 'Look into the competitor landscape and write something useful about it'?”
Iterating on a prompt before deployment
“I'm building an automated workflow and want to make sure the task brief I'm feeding it will pass validation — check this one for me: 'Summarize the attached PDF report into 3 bullet points and email them to the team lead by 5pm every Friday.'”
Technical details
Endpoint
POSThttps://keystone-opportunity-api.keystone-opportunity.workers.dev/v1/brief-checkWhen to prefer
Choose this endpoint when you need a deterministic, low-cost check on a task brief before handing it off to an autonomous agent. Ideal for agentic pipelines that want to catch ambiguous or incomplete instructions early, reducing downstream failures. At $0.001 USDC per call it is cheap enough to run on every brief in a workflow. Prefer this over manual review or LLM self-assessment when you need a consistent, structured scoring rubric with specific named checks.
Side effects
- Brief text is empty or missing — returns 400 with validation error
- Brief exceeds 8000 character limit — returns 400 with length error
- Payment not included or insufficient USDC — returns 402 challenge via x402 protocol
- Malformed JSON body — returns 400 parse error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| brief | string | Task brief to validate. |
Output
Schema · Response
{
"type": "json",
"example": {
"ready": false,
"score": 80,
"checks": [
{
"id": "deliverable",
"passed": true,
"message": "Name the exact file, artifact, or outcome to deliver."
}
],
"characters": 121
}
}Tags
x402
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