# GateCheck by LarryBuildsAI – x402 Agent Tool Preflight Scanner

> GateCheck by LarryBuildsAI – x402 Agent Tool Preflight Scanner is a paid API for AI agents from x402-resource-scanner.vercel.app, paid per call via x402, $0.25/call, status unknown (last checked 2026-09-14).

Performs preflight readiness checks on a URL to verify it is properly configured as a paid x402 agent tool before marketplace listing, including seller-readiness, unpaid path probes, and launch-pack artifact validation.

## Facts

- Endpoint: GET https://x402-resource-scanner.vercel.app/v1/x402/scan
- Price: $0.25/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/gatecheck-by-larrybuildsai-x402-agent-tool-preflight-scanner-21d28dbb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_xStBlLxzcJJEW2vU-Yg_1

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-agent-tool-preflight-scanner-21d28dbb
```

Example prompt: Run GateCheck preflight scans on https://my-agent-tool.example.com before I list it — I'm expecting 3 paid resources and my marketplace listing is at https://marketplace.example.com/tools/my-tool.

## When to prefer this

Use this endpoint when you need to programmatically verify that a paid x402 agent tool endpoint is correctly configured and ready for marketplace listing — specifically when you want automated seller-readiness checks, unpaid path probing, and launch-pack artifact validation in one call, rather than manually inspecting x402 headers or guessing at compliance.

## Known failure modes

- Target URL is unreachable or returns unexpected status codes
- URL does not implement x402 payment headers correctly, causing probe failures
- Expected resource count mismatch triggers validation error
- Marketplace URL is invalid or inaccessible
- Endpoint times out if target server is slow to respond
- Missing launch-pack artifacts cause listing readiness to fail

## 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 preflight report covering x402 seller-readiness status, results of unpaid path probes against the target URL, and validation of launch-pack artifacts required for marketplace listing, including pass/fail details for each check.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "url"
 ],
 "properties": {
  "url": {
   "type": "string"
  },
  "marketplace_url": {
   "type": "string"
  },
  "expected_resources": {
   "type": "integer"
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/gatecheck-by-larrybuildsai-x402-agent-tool-preflight-scanner-21d28dbb/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)