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x402 Payment-Security Posture Auditor
x402
x402 Payment-Security Posture Auditor is a paid API for AI agents from agent402.tools, paid per call via x402, $0.01/call, status unknown (last checked 2026-09-13).
Black-box audits an x402-protected URL for payment-security vulnerabilities without making a payment, scoring TLS transport, cache hygiene, and gated-response exposure against the Five Attacks on x402 failure modes.
Price / call$0.01
Success—
StatusUnknown
How this service works
Grade any x402 seller's payment-security posture from the outside - a read-only black-box check mapped to the 'Five Attacks on x402' failure modes. Probes the URL's 402 challenge (never pays) and scores TLS transport, gated-response cache hygiene (Attack III / cache leakage), error/info-leak hygiene, and payment-terms well-formedness, then returns a letter grade with per-check findings and an honest note on what only insider/active testing can confirm.
Output
Returns a structured security posture report for the probed x402 endpoint, including a numeric score, TLS transport grade, cache hygiene evaluation, and per-failure-mode findings mapped to the Five Attacks on x402 taxonomy — all derived without submitting any payment.
Example use cases
Example prompt
“Run a black-box x402 security audit on https://api.example.com/premium-data — check the TLS grade, cache hygiene, and whether it passes the Five Attacks failure mode tests without me actually paying anything.”
Technical details
Endpoint
GEThttps://agent402.tools/api/x402-auditWhen to prefer
Use this endpoint when you need a read-only, non-paying security assessment of any x402-gated resource — particularly when you want to verify that a seller's 402 implementation is hardened against known attack patterns (cache bypass, response leakage, weak TLS) before integrating with it or publishing it as a trusted service. Prefer this over manual inspection when you need a structured, scored report mapped to the Five Attacks taxonomy.
Side effects
- Target URL is not a valid x402 endpoint (no 402 challenge returned) — audit cannot proceed
- Target host is unreachable or times out — returns connection error
- URL is malformed or missing — returns 400 validation error
- Target blocks probe user-agent or IP — incomplete results with partial scoring
- TLS handshake failure at target — TLS score marked as failed with error detail
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| inputrequired | object | |
| output | object |
Output
Schema · Response
{
"type": "json",
"example": {
"url": "https://api.example.com/paid",
"grade": "A",
"score": 92,
"checks": [
{
"id": "transport-tls",
"title": "Payment challenge served over TLS",
"attack": "credential interception",
"detail": "https",
"status": "pass",
"severity": "high"
},
{
"id": "cache-hygiene",
"title": "Gated response is not shared-cacheable",
"attack": "III - cache leakage",
"detail": "Cache-Control: no-store, private",
"status": "pass",
"severity": "high"
}
],
"status": 402,
"summary": "A (92/100) - 6 passed, 1 warning, 0 failed. Note: replay/idempotency (II) and router Sybil (IV) can't be graded from outside.",
"reachable": true,
"x402Version": 2,
"paymentRequired": true
}
}Tags
x402
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