# QuietSignal Public Page Safety Scanner

> QuietSignal Public Page Safety Scanner is a paid API for AI agents from 83-29-153-50.sslip.io, paid per call via x402, $0.01/call, status down (last checked 2026-09-15).

Screens a public HTTP/HTTPS URL for deterministic prompt-injection indicators and returns a risk level assessment.

## Facts

- Endpoint: GET https://83-29-153-50.sslip.io/v1/public-page-safety
- Price: $0.01/call
- Payment: x402
- Status: down
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/quietsignal-public-page-safety-scanner-8c8e6fcb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XycgRiB1Q5aOfJse6qmcw

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 quietsignal-public-page-safety-scanner-8c8e6fcb
```

Example prompt: Before my agent reads that article at https://example.com/blog/post, can you scan it for prompt injection indicators and tell me if it's safe — following up to 3 redirects?

## When to prefer this

Choose this endpoint when an AI agent needs a lightweight, deterministic pre-flight safety check on a URL before fetching or processing its content — particularly to guard against prompt injection attacks embedded in third-party web pages. It is well-suited for agentic pipelines that consume external URLs from users or untrusted sources. It is not a substitute for a full security audit and should not be used for deep vulnerability scanning or malware detection.

## Known failure modes

- Invalid or malformed URL returns a validation error
- URL is not publicly reachable returns a connection or timeout error
- Exceeding max_redirects limit causes the scan to abort with a redirect error
- Non-HTTP/HTTPS URLs (e.g. ftp://) are rejected by schema validation
- Payment not received results in HTTP 402 response before scan executes

## How this service works

QuietSignal Public Data: independent, read-only rollup, wallet, opportunity, and developer-data facts for agents, paid per request with USDC over HTTP 402 on Base.

## Output

Returns a JSON object with a scan schema identifier, the HTTP status code of the scanned page, a list of detected prompt-injection indicators (empty if none found), a risk level string (e.g. 'none', 'low', 'medium', 'high'), an indicator count, the scan engine version, and a disclaimer noting this is deterministic screening only and not a full security audit.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "url"
     ],
     "properties": {
      "url": {
       "type": "string",
       "format": "uri",
       "description": "Public HTTP(S) page to screen for deterministic prompt-injection indicators"
      },
      "max_redirects": {
       "type": "integer",
       "maximum": 5,
       "minimum": 0,
       "description": "Maximum validated public redirects to follow"
      }
     },
     "additionalProperties": false
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "json",
 "example": {
  "scan": {
   "engine": "deterministic-patterns/1",
   "indicators": [],
   "risk_level": "none",
   "indicator_count": 0
  },
  "schema": "public-page-safety/v1",
  "disclaimer": "Deterministic screening signals only; not a security audit or proof that a page is safe.",
  "status_code": 200
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/quietsignal-public-page-safety-scanner-8c8e6fcb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from 83-29-153-50.sslip.io](https://www.zero.xyz/host/83-29-153-50.sslip.io/llms.txt)