# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from x402broker.com, paid per call via MPP, $0.005/call, status unknown (last checked 2026-10-21).

Scans untrusted text, HTML, emails, MCP responses, or A2A payloads for hidden prompt injections and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: GET https://x402broker.com/v1/guard?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: x402broker.com
- Website: https://x402broker.com
- Canonical page: https://www.zero.xyz/c/x402broker-com-a2a-indirect-prompt-injection-jailbreak-firewall-97548ffb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ywCMUDuMQ9165_d7SjYMM

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 x402broker-com-a2a-indirect-prompt-injection-jailbreak-firewall-97548ffb
```

Example prompt: Before you process this scraped web page content, run it through the prompt injection firewall to check for any hidden jailbreak instructions and give me the sanitized version: '<html>...untrusted content here...</html>'

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests content from untrusted external sources — scraped web pages, user-submitted text, third-party API responses, MCP tool outputs, or A2A payloads — and you need to sanitize them before passing to an LLM. Prefer this over manual filtering when you need automated, real-time detection of indirect prompt injection and jailbreak patterns specifically designed to exploit AI agents.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Extremely long input text may be truncated or rejected
- False negatives: novel or obfuscated injection patterns may not be detected
- False positives: legitimate instructional text may be incorrectly flagged
- Payment failure (402) if USDC balance is insufficient
- Service unavailability returns 5xx errors

## How this service works

Scans untrusted web pages, emails, MCP responses, or A2A payloads for hidden prompt injections and returns sanitized text. (Live x402 v2, IETF MPP & MCP endpoint at https://x402broker.com/v1/guard)

## Output

Returns a structured object containing the sanitized version of the input text with any detected prompt injection or jailbreak payloads removed or flagged, along with detection metadata indicating whether malicious content was found.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "text"
 ],
 "properties": {
  "text": {
   "type": "string",
   "minLength": 1,
   "description": "Untrusted text, HTML, or tool output to scan for hidden prompt injection or jailbreak payloads"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/x402broker-com-a2a-indirect-prompt-injection-jailbreak-firewall-97548ffb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402broker.com](https://www.zero.xyz/host/x402broker.com/llms.txt)