01
Money facts
Price, protocol, network, asset, payment destination, and available machine-payment offers.
Agent task · payment preflight
Check an autonomous agent purchase before payment.
check_agent_purchase validates a real HTTP 402 challenge before the calling agent authorizes the target payment. The completed specialist check costs $0.01 USD on compatible stablecoin machine-payment rails.
What it verifies
Make the payment boundary explicit before funds move.
ExitProof normalizes the observed challenge and compares it to advertised terms when supplied. Material conflicts fail before ExitProof issues its own one-cent payment challenge.
02
Request binding
For x402 v2 exact challenges, verify that the payment resource URL matches the endpoint the agent intends to call.
03
Recovery signals
Surface published idempotent-retry, settled-delivery recovery, and refund or reversal metadata when the caller supplies it.
Safe observation
ExitProof never spends to test a purchase.
For GET or HEAD targets, ExitProof can make one anonymous request with no authorization, cookies, wallet proof, or payment credential and inspect the resulting 402. For POST, PUT, PATCH, or DELETE, ExitProof will not send an active probe: the calling agent supplies the 402 challenge it already observed.
Eligible evidence
- live anonymous GET or HEAD returning HTTP 402
- caller-observed PAYMENT-REQUIRED x402 v2 header
- caller-observed WWW-Authenticate MPP Payment challenge
- optional advertised payment and recovery metadata
Rejected before payment
- non-HTTPS, localhost, or private-address targets
- state-changing live probes
- missing or unparseable payment challenges
- conflicting price, protocol, network, asset, destination, or resource binding
Result
Two bounded outcomes, never a purchase recommendation.
eligible_to_attempt means the observed payment requirements are internally consistent with supplied expectations and a positive retry or recovery signal was supplied. review_required means no contradiction was found, but one or more safety facts remain unknown.
Price$0.01 per completed authorized check
HTTP paymentx402 v2 / USDC when configured
MCP paymentTempo stablecoin MPP when configured
No card fallbackthe one-cent route does not fall through to the ordinary card PaymentIntent path
Privacyno target payment credential, raw prompt, cookie, or authorization header is retained or forwarded
Decisionthe calling agent remains responsible for whether to spend