# SpendGuard x402 Pre-Payment Honesty Check

> SpendGuard x402 Pre-Payment Honesty Check is a paid API for AI agents from spendguard.panmediatech.workers.dev, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Live-probes a resource URL for a valid x402 Payment Required challenge and returns allow/caution/block verdict with signals before an AI agent pays

## Facts

- Endpoint: POST https://spendguard.panmediatech.workers.dev/x402/check
- Price: $0.005/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/spendguard-x402-pre-payment-honesty-check-9dbab5c0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QcUnzQWy8XrLo9_whNEpw

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability spendguard-x402-pre-payment-honesty-check-9dbab5c0 -d '<json body>'
```

Example prompt: Before I pay that x402 endpoint at https://api.example.com/data, run a SpendGuard honesty check on it — my budget is $0.10 USDC on Base — and tell me whether I should allow, treat with caution, or block the payment.

## When to prefer this

Use this endpoint whenever an AI agent is about to make an x402 micropayment and needs a pre-payment sanity check — especially when the resource URL is unknown, third-party, or discovered dynamically (e.g. from a Bazaar listing). Prefer this over trusting raw 402 headers directly, particularly when budget constraints or wallet address verification matter. Not suitable as a post-payment delivery proof mechanism.

## Known failure modes

- Resource URL is unreachable or returns non-402 status — endpoint may return block verdict with signals indicating no valid challenge
- payTo address missing or malformed in 402 challenge — verdict likely caution or block
- Network mismatch between detected chain and expected budget network — caution signal raised
- Service itself unavailable or Worker error — HTTP 500 with no verdict
- Malicious resource attempts to spoof valid 402 headers — signals may not catch all sophisticated spoofs

## How this service works

Should I pay this x402 endpoint? Pre-payment honesty check for AI agents: live-probe any resource URL for a valid 402 Payment Required challenge, match payTo and budget, return allow/caution/block with signals. Bazaar seller readiness before spend. Not post-payment delivery proof. $0.005 USDC on Base.

## Output

Returns a JSON object with a numeric score, a verdict enum (allow/caution/block), an array of signals explaining the assessment, a human-readable summary, the resource URL that was checked, the detected network, the payTo wallet address found in the 402 challenge, a checked_at timestamp, and a cache hit/miss indicator.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/spendguard-x402-pre-payment-honesty-check-9dbab5c0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from spendguard.panmediatech.workers.dev](https://www.zero.xyz/host/spendguard.panmediatech.workers.dev/llms.txt)