# 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/mcp-injection-firewall?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-aa641603
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_4tV-C5aWMpmiO_wLq8laP

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-aa641603
```

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

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests text from untrusted external sources — scraped web pages, emails, MCP tool responses, or A2A payloads — and you need to detect and neutralize hidden prompt injection or jailbreak attempts before processing. Especially valuable in agentic workflows where LLMs act autonomously on external content and are vulnerable to indirect prompt injection attacks.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely long payloads may be truncated or rejected
- False negatives possible for novel or obfuscated injection techniques
- Service unavailability or payment failure returns HTTP 402 or 5xx
- Highly encoded or multi-language injections may evade detection

## 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/mcp-injection-firewall)

## Output

Returns a JSON object containing the sanitized version of the submitted text with any detected prompt injection or jailbreak payloads neutralized, along with detection signals 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-aa641603/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)