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X402 Quote Comparison and Selection Decision Procedure
x402
X402 Quote Comparison and Selection Decision Procedure is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-10-31).
Generates an AI-written decision procedure for agents to collect, normalize, and select the best quote from multiple x402 merchants without accounts or OAuth, including trust scoring and fallback logic.
Price / call$0.002
Success—
StatusDown
How this service works
Decision procedure for an agent buying one service from multiple x402 merchants without accounts or OAuth. Collects offers, probes each for real 402 challenges, normalizes quotes to comparable units (total cost incl fees, settlement latency, data freshness), applies merchant trust tier and kill criteria (404/405 weak contracts, mismatched payTo, stale offers), then selects the winning quote with explicit rationale and records a runner-up for re-quote fallback. Returns a ranked quote table with
Output
Returns a JSON object containing a prose decision procedure (120+ words) for agents to follow when comparing and selecting x402 merchant quotes, including ranked quote table logic, kill criteria, trust tier application, winner rationale, and runner-up fallback. Also includes metadata such as model used, generation source, timestamp, and service/provider identifiers.
Example use cases
Multi-merchant grocery service selection
“I have three x402 grocery shopping agents quoting me different prices and settlement speeds — give me a ranked comparison procedure so I can pick the best one, including how to spot mismatched payTo addresses and keep a runner-up in case the winner's quote goes stale.”
x402 fee and latency normalization
“My agent needs to buy a real-time data feed from one of five x402 merchants, but they all quote in different units and some charge extra fees — give me a procedure to normalize everything to total cost and settlement latency so I can make an apples-to-apples comparison.”
Merchant trust scoring before settlement
“Before my agent commits to paying any x402 merchant, I want it to apply trust tiers and kill criteria — like rejecting anyone with a 404 weak contract or a payTo mismatch — can you give me the decision procedure for that screening process with rationale?”
Technical details
Endpoint
GEThttps://k2so.wrong.systems/api/services/rt-nichxbt-x402-ai-agent-grocery-shopping-an-age?utm_source=zero.xyzWhen to prefer
Use this endpoint when an AI agent must autonomously choose one x402-priced service from multiple competing merchants without user accounts or OAuth, especially when offers differ in fee structure, settlement rails, or data freshness. Prefer this over generic comparison logic when you need x402-specific kill criteria (404 weak contracts, payTo mismatch detection) and a structured fallback to a runner-up quote. Not appropriate for non-x402 payment rails or scenarios requiring real-time streaming price feeds.
Side effects
- Payment not provided — endpoint returns HTTP 402 requiring USDC payment before content is delivered
- Invalid HTTP method — only GET, HEAD, DELETE accepted; POST/PUT will be rejected
- Stale or expired merchant offers — procedure may flag offers as invalid if probed 402 challenges are outdated
- No topic override provided — procedure defaults to the embedded grocery shopping service slug
- LLM generation failure — generationSource may fall back to deterministic mode with reduced prose quality
- Network timeout to k2so.wrong.systems — agent receives no response and must retry
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"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": "rt-nichxbt-x402-ai-agent-grocery-shopping-an-age",
"procedure": "same as brief",
"generatedAt": "2026-01-01T00:00:00.000Z",
"generationSource": "deterministic"
},
"service": "rt-nichxbt-x402-ai-agent-grocery-shopping-an-age",
"provider": "K-2SO"
}
}Tags
x402
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