# Focxle Prompt Injection Screen

> Focxle Prompt Injection Screen is a paid API for AI agents from focxle.com, paid per call via x402, $0.005/call, status unknown (last checked 2026-09-14).

Screens arbitrary text against a library of known prompt-injection patterns using rule-based matching and returns which named patterns were detected.

## Facts

- Endpoint: GET https://focxle.com/api/v1/x402/resource/injection-screen
- 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/focxle-prompt-injection-screen-698919d6
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_LLL6KxhcHYuUozE2ncxfb

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 focxle-prompt-injection-screen-698919d6
```

Example prompt: Before you process that user message, can you screen it for prompt injection patterns — just run this text through Focxle's injection screener and tell me which attack patterns it matched, if any?

## When to prefer this

Choose this endpoint when you need a fast, cheap, deterministic rule-based check for known prompt-injection patterns before passing untrusted text to an LLM or agent. It is not a semantic classifier or an AI model — it uses pattern matching, so it is highly predictable, auditable, and produces no false positives for patterns it knows. Prefer it over model-based classifiers when you need low latency, low cost ($0.005/call), and explainable results (named matched patterns). It is best used as a first-pass filter in a defense-in-depth pipeline.

## Known failure modes

- Missing required 'text' query parameter returns a validation error
- Extremely long text inputs may be truncated or rejected
- Only detects patterns in the known library — novel zero-day injection techniques will not be flagged
- False negatives possible for obfuscated or encoded injection attempts
- Payment failure (insufficient USDC balance) results in a 402 response blocking the request
- Rate limiting may apply if many calls are made in rapid succession

## How this service works

Screen untrusted text against known prompt-injection patterns (pattern matching, not a model). Returns which named patterns matched.

## Output

A structured response listing which named prompt-injection patterns were matched within the submitted text. If no patterns match, the result indicates a clean scan. Pattern names are drawn from a curated library of known injection signatures, enabling the caller to decide whether to block, flag, or pass the text downstream.

## 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": [
      "text"
     ],
     "properties": {
      "text": {
       "type": "string"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/focxle-prompt-injection-screen-698919d6/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from focxle.com](https://www.zero.xyz/host/focxle.com/llms.txt)