# GateCheck by LarryBuildsAI – x402 Preflight Receipt Check

> GateCheck by LarryBuildsAI – x402 Preflight Receipt Check is a paid API for AI agents from x402-resource-scanner.vercel.app, paid per call via x402, $0.05/call, status unknown (last checked 2026-09-15).

Runs preflight seller-readiness checks and unpaid x402 paid-path probes on an agent tool before marketplace listing, returning a structured receipt of gate results.

## Facts

- Endpoint: POST https://x402-resource-scanner.vercel.app/v1/receipts/check
- Price: $0.05/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gatecheck-by-larrybuildsai-x402-preflight-receipt-check-538fd132
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_cqGpNspWUu4h4HlJtkBfO

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 gatecheck-by-larrybuildsai-x402-preflight-receipt-check-538fd132 -d '<json body>'
```

Example prompt: Run a GateCheck preflight on my paid agent tool at https://myagentapi.example.com/v1/generate — I want the full seller-readiness report and x402 paid-path probe results so I can see if it's ready to list on the marketplace.

## When to prefer this

Use this endpoint when you are a developer or agent builder who needs to validate that a paid x402 agent tool endpoint is correctly configured and seller-ready before submitting it to an agent marketplace. It is specifically designed for the x402 micropayment ecosystem and produces structured receipts with launch-pack artifacts, making it the right choice over generic HTTP probers or uptime checkers.

## Known failure modes

- Target URL is unreachable or returns non-x402 response — probe fails with connection or format error
- Tool endpoint is not x402-compliant — returns gate failure with specific misconfiguration details
- Invalid or missing target URL in request body — returns 400 bad request
- Endpoint times out during probe — returns timeout error in receipt
- x402 payment header misconfigured on target — probe reports payment-path failure

## How this service works

Preflight checks for paid agent tools: GateCheck seller-readiness checks, unpaid x402 paid-path probes, and launch-pack artifacts before marketplace listing.

## Output

Returns a structured receipt containing seller-readiness check results, x402 paid-path probe outcomes (unpaid probes only), and launch-pack artifacts indicating whether the tool is ready for marketplace listing, including any blocking issues or warnings.

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/gatecheck-by-larrybuildsai-x402-preflight-receipt-check-538fd132/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-resource-scanner.vercel.app](https://www.zero.xyz/host/x402-resource-scanner.vercel.app/llms.txt)