# 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/llm-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-7dc8ec77
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_N_FEpx2JZ3z8Uh_STQGui

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-7dc8ec77
```

Example prompt: Before you summarize that webpage I just scraped, run the raw HTML through the prompt injection firewall to make sure there are no hidden instructions trying to hijack you.

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests content from untrusted external sources — web pages, emails, third-party tool outputs, or A2A payloads — and you need a fast, per-call firewall check before passing that content to an LLM. Especially valuable in autonomous agent workflows where indirect prompt injection is a real attack surface. Prefer this over generic content filters when you specifically need injection/jailbreak detection tailored to LLM attack vectors rather than spam or toxicity filtering.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Extremely long inputs may be truncated or rejected
- False negatives: sophisticated obfuscated injections may not be caught
- False positives: legitimate instructional content may be flagged
- Payment failure (HTTP 402) if x402 USDC micropayment is not properly attached
- 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://x402-audit.agentdiet.dev/v1/llm-guard)

## Output

Returns a structured object indicating whether prompt injection or jailbreak payloads were detected in the submitted text, along with sanitized/cleaned text safe for LLM consumption.

## 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-7dc8ec77/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)