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x402 Payment-Terms Health Validation & MCP Tool Cost Pre-Flight
x402
x402 Payment-Terms Health Validation & MCP Tool Cost Pre-Flight is a paid API for AI agents from k2so.wrong.systems, paid per call via x402, $0.002/call, status down (last checked 2026-10-30).
Returns a decision procedure brief for validating a 402 challenge's payment terms before paying and for evaluating whether an MCP/x402 tool call is worth its per-call cost under budget caps.
Price / call$0.002
Success—
StatusDown
How this service works
Paid agent-facing brief on agent-facing x402 payment-terms health validation and MCP tool cost pre-flight: a procedure for validating that a 402 challenge's payment terms are well-formed (WWW-Authenticate scheme, amount, asset, network, timeout, expiry) BEFORE paying, distinguishing up-but-malformed from up-and-payable, plus deciding whether an MCP/x402 tool call is worth its unknown per-call cost under budget caps. Distinc-0. Blunt decision procedure, not marketing.
Output
A structured brief containing a decision procedure in prose form: whether the 402 challenge's payment terms are well-formed across all required fields (scheme, amount, asset, network, timeout, expiry), a clear verdict distinguishing up-but-malformed from up-and-payable, and guidance on whether an MCP/x402 tool call is worth its cost under budget constraints. Response includes ok/paid flags, service slug, provider, generation source, and ISO-8601 timestamp.
Example use cases
Pre-flight check before agent pays 402
“I just got a 402 response from an API with a WWW-Authenticate header. Can you validate the payment terms — scheme, amount, asset, network, timeout, and expiry — and tell me if this is safe and well-formed enough to actually pay?”
MCP tool cost evaluation against budget
“I'm about to call an MCP tool that charges an unknown per-call fee. My budget cap is $0.05 per call — can you run a cost pre-flight and tell me whether this tool call is worth authorizing under that cap?”
Distinguishing malformed vs payable 402
“This endpoint is returning a 402 but something feels off about the payment challenge. Can you diagnose whether it's up-but-malformed or genuinely up-and-payable, and give me a blunt decision on whether to proceed?”
Technical details
Endpoint
GEThttps://k2so.wrong.systems/api/services/agent-facing-x402-payment-terms-health-validatio?utm_source=zero.xyzWhen to prefer
Choose this endpoint when an AI agent needs a structured, blunt decision procedure for validating x402 payment challenges before spending — especially when distinguishing malformed challenges from legitimate ones, or when evaluating whether an MCP tool's unknown per-call cost is within acceptable budget bounds. Prefer this over general payment libraries when you need reasoned prose guidance rather than a simple pass/fail boolean.
Side effects
- Malformed input object or missing required fields returns a validation error
- If the service is unavailable, no brief is generated
- LLM generation failure may result in an empty or partial brief field
- Ambiguous or missing topic parameter may yield a generic rather than targeted procedure
- Payment not completed results in a non-paid response without the full brief content
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Tags
x402
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