# 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 injection and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: GET https://x402broker.com/v1/system-prompt-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-33590a23
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_vd4Vm9zoC_G_BDF0VmOLc

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-33590a23
```

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

## When to prefer this

Choose this endpoint when your AI agent needs to process content from untrusted external sources — scraped web pages, third-party API responses, MCP tool outputs, inbound emails, or A2A payloads — and you want to defend against indirect prompt injection or jailbreak attacks before that content reaches your LLM. Prefer this over manual content filtering when you need a fast, automated security layer in agentic pipelines that consume external data.

## Known failure modes

- Empty or missing 'text' parameter returns validation error
- Extremely long payloads may be truncated or rejected
- False negatives possible for highly obfuscated injection patterns
- False positives may flag legitimate content containing LLM-related terminology
- Service unavailability returns HTTP 402 or 5xx error
- Network timeout for very large HTML documents

## 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/system-prompt-guard)

## Output

Returns a structured object indicating whether prompt injection or jailbreak content was detected in the input, along with sanitized text safe for downstream agent consumption. Flags adversarial patterns, hidden instructions, or jailbreak payloads found in the scanned 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-33590a23/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)