# Sentinel URL Consensus Checker

> Sentinel URL Consensus Checker is a paid API for AI agents from sentinel.rootstuff.io, paid per call via x402, $0.02/call, status unknown (last checked 2026-09-15).

Runs a four-region distributed consensus probe on a URL to verify its reachability and behavior

## Facts

- Endpoint: GET https://sentinel.rootstuff.io/x402/check
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/sentinel-url-consensus-checker-a2a9febb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_G1aw0Hdm85J9cqXwXaM74

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 sentinel-url-consensus-checker-a2a9febb
```

Example prompt: Can you run a four-region consensus check on https://api.example.com/health to see if it's reachable globally?

## When to prefer this

Choose this endpoint when you need a geographically distributed, multi-region view of URL availability rather than a single-point ping. It is ideal for diagnosing whether a site is down globally versus locally, validating public endpoints before launch, or checking third-party dependency health from a consensus perspective.

## Known failure modes

- Private or reserved IP addresses are refused with an error
- Malformed or non-HTTP/HTTPS URLs are rejected
- Target host may time out in one or more regions, affecting consensus
- URL may be reachable in some regions but not others, resulting in split consensus
- Rate limiting or payment failure may block the request

## How this service works

Four-region consensus check of a URL

## Output

A consensus result from four geographic regions indicating whether the URL is reachable and consistent, including per-region probe outcomes and an overall availability verdict.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "url": {
   "type": "string",
   "description": "The http(s) URL to probe. Public hosts only; private and reserved addresses are refused."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/sentinel-url-consensus-checker-a2a9febb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from sentinel.rootstuff.io](https://www.zero.xyz/host/sentinel.rootstuff.io/llms.txt)