# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from x402-audit.agentdiet.dev, 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://x402-audit.agentdiet.dev/v1/injection-guard?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: x402-audit.agentdiet.dev
- Website: https://x402-audit.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/x402-audit-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-859758fc
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_i1JHhU9X67LVGKvJjyIuc

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 x402-audit-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-859758fc
```

Example prompt: Before you process that web page I just scraped, run the content through the injection-guard firewall to check for any hidden prompt injections or jailbreak payloads — here's the raw HTML text.

## When to prefer this

Use this endpoint whenever an AI agent needs to process text from untrusted external sources — scraped web pages, inbound emails, third-party tool responses, or A2A/MCP payloads — before acting on them. It is the right choice when protecting LLM pipelines against indirect prompt injection, jailbreaks, or hidden instruction attacks embedded in content the agent did not generate itself.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Extremely large payloads may be truncated or rejected
- False negatives possible for novel or obfuscated injection techniques
- Service unavailable or timeout if the x402 endpoint is unreachable
- Payment required (HTTP 402) if USDC balance is insufficient for the $0.005 per-call fee

## 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://x402-audit.agentdiet.dev/v1/injection-guard)

## Output

Returns a structured object indicating whether prompt injection or jailbreak content was detected, along with sanitized text with malicious instructions stripped or flagged, allowing the agent to safely continue processing the input.

## 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/x402-audit-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-859758fc/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-audit.agentdiet.dev](https://www.zero.xyz/host/x402-audit.agentdiet.dev/llms.txt)