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x402 Retry and Replay-Control Verification Pre-Payment Procedure
x402
x402 Retry and Replay-Control Verification Pre-Payment Procedure is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status unknown (last checked 2026-10-30).
Returns a paid decision brief for agents on how to verify a merchant's replay protection, idempotency keys, nonce/session binding, and retry semantics before settling USDC via x402, to prevent double-settlement.
Price / call$0.002
Success—
StatusUnknown
How this service works
Paid agent-facing procedure on x402 retry and replay-control verification: pre-payment checklist for agents to verify a merchant's replay protection (idempotency keys, nonce/session binding, receipt linkage, retry semantics) so a network retry or duplicated intent cannot double-settle USDC, plus spend-policy boundary checks on the facilitator margin. Blunt decision procedure, not marketing.
Output
A paid prose decision brief (the 'brief' field) containing a blunt go/no-go procedure for agents, covering: replay protection adequacy (idempotency keys, nonce/session binding, receipt linkage), retry semantics assessment, and spend-policy boundary checks on facilitator margin. Also returns metadata including service slug, generation source (llm/reasoning/deterministic), ISO-8601 timestamp, and payment confirmation details.
Example use cases
Pre-settlement double-payment risk check
“I'm about to send a USDC payment over x402 but the network has been flaky — can you verify whether the merchant has proper replay protection and idempotency controls so a retry won't charge me twice?”
Facilitator spend-policy boundary audit
“Before my agent finalizes this x402 transaction, check the facilitator margin spend-policy boundaries and confirm the replay controls are in place so we're not violating any spending limits.”
Duplicate intent safety gate for autonomous agent
“My autonomous agent is handling a batch of x402 payments and I need to make sure none of them can be double-settled due to a duplicated intent — run the retry and replay-control verification procedure and give me the blunt go/no-go decision.”
Technical details
Endpoint
GEThttps://k2so.wrong.systems/api/services/x402-retry-and-replay-control-verification-pre-p?utm_source=zero.xyzWhen to prefer
Choose this endpoint when an agent is about to execute an x402 USDC payment and needs a structured, blunt decision procedure specifically for verifying replay and retry safety — particularly when network conditions are unreliable, when the merchant is unknown, or when spend-policy compliance must be confirmed before settlement. Prefer this over generic payment validation when the specific concern is double-settlement via network retry or duplicated payment intent in the x402 protocol context.
Side effects
- Payment not provided — returns HTTP 402 requiring USDC micropayment before brief is delivered
- Invalid method — only GET/HEAD/DELETE accepted
- Merchant replay protection data unavailable — brief may be generated with incomplete context
- LLM generation failure — generationSource falls back to deterministic or returns error
- Topic override not recognized — defaults to standard x402 retry/replay procedure
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": "x402-retry-and-replay-control-verification-pre-p",
"procedure": "same as brief",
"generatedAt": "2026-01-01T00:00:00.000Z",
"generationSource": "deterministic"
},
"service": "x402-retry-and-replay-control-verification-pre-p",
"provider": "K-2SO"
}
}Tags
x402
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