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Tereno x402 Endpoint Assurance
x402
Tereno x402 Endpoint Assurance is a paid API for AI agents from www.tereno.xyz, paid per call via x402, $0.03/call, status unknown (last checked 2026-09-14).
Probe and validate a third-party x402 endpoint's 402 challenge conformance, schema quality, availability history, and field-level changes since last observation without paying it.
Price / call$0.03
Success—
StatusUnknown
How this service works
Verify and monitor a third-party x402 endpoint without paying it. Probe the live 402 challenge and check conformance: price, payTo, network, scheme, schema and example quality, whether its own advertised input still reaches a challenge, and whether its description fits the facilitator limit that silently blocks settlement. Then get availability history and a field-level diff since the last observation. Optional recomputation against Base.
Output
Returns a conformance report covering the live 402 challenge fields (price, payTo, network, scheme), schema and example quality assessment, whether the endpoint's own advertised input triggers a 402, whether the description fits within facilitator settlement limits, availability history, and a field-level diff versus the last recorded observation. If an observed response and claims are supplied, also returns recomputed blockchain claim verdicts against Base.
Example use cases
Audit new x402 API before integration
“Before I integrate with this x402 API at https://api.partner.com/v1/feed, can you probe its 402 challenge and tell me if the price, payTo, network and schema all look correct, and whether the facilitator limit would silently block my payments?”
Detect x402 endpoint drift after update
“The x402 endpoint at https://service.xyz/premium-data changed something recently — can you compare it against the last observation and show me a field-level diff of whatever moved, especially price or payTo?”
Recompute Base claims from paid response
“I already have a paid response from https://data.defi.io/x402/prices — can you recompute the ERC-20 symbol and balance claims in it against Base to confirm they were accurate when I received them?”
Technical details
Endpoint
POSThttps://www.tereno.xyz/api/v1/x402/assurance/invokeWhen to prefer
Use this endpoint when you need to validate a third-party x402 endpoint's protocol conformance, monitor it for drift, or audit its challenge fields without incurring a payment. Prefer it over manual inspection when you need availability history, automated schema quality scoring, facilitator-limit risk detection, or Base claim recomputation from a held response. It is the right choice any time you want assurance about an x402 endpoint's correctness before committing funds or building an integration against it.
Side effects
- Target URL is unreachable or returns non-402 status unexpectedly
- x402 challenge response is malformed and cannot be parsed
- Facilitator limit check cannot be evaluated without sufficient description metadata
- Blockchain claim recomputation fails if Base RPC is congested or address is invalid
- Request times out if the target endpoint is slow to respond
- Invalid method enum value causes input validation error
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| body | object | JSON body to send with the probe, for POST resources. |
| query | object | Query parameters to send with the probe. |
| claims | array | What to recompute out of observedResponse. Supported kinds: erc20.symbol, erc20.decimals, erc20.totalSupply, erc20.balanceOf, native.balance, contract.hasCode, gas.priceGwei. |
| method | — | How that endpoint is normally called. Defaults to GET. |
| resource | string | Absolute HTTPS URL of the x402 endpoint to measure. |
| observedResponse | object | A paid response you already hold from that endpoint. Supply it to have its claims recomputed against Base. |
Tags
x402
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