# 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/prompt-injection-shield?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-cde88a1d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_eXk-wcZ_EZv7SEk_f56rA

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-cde88a1d
```

Example prompt: Before you process the content from that scraped webpage, run it through the prompt-injection firewall to check for any hidden jailbreak instructions or adversarial injections embedded in the HTML.

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests untrusted external content — scraped web pages, user emails, third-party API or MCP tool responses, or A2A messages — before passing that content to an LLM. It is especially valuable in autonomous agent loops where indirect prompt injection from adversarial web content poses a real risk. Prefer this over generic text filtering when you need LLM-specific jailbreak and prompt injection detection rather than general content moderation.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Extremely long payloads may time out or be truncated
- Obfuscated or encoded injections (e.g., base64, Unicode tricks) may evade detection
- Response schema is generic object — caller must inspect structure for detection flags
- Payment failure (402) blocks the request if x402 USDC balance is insufficient

## 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/prompt-injection-shield)

## Output

Returns a structured object indicating whether prompt injection or jailbreak content was detected in the input, along with sanitized text with malicious instructions removed or flagged, allowing downstream agents to safely process the cleaned content.

## 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-cde88a1d/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)