# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from mcp-compiler.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://mcp-compiler.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: mcp-compiler.agentdiet.dev
- Website: https://mcp-compiler.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/mcp-compiler-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-73bda6ae
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_RxY8fmts9M_zphRWMI9g1

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 mcp-compiler-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-73bda6ae
```

Example prompt: Before processing this scraped webpage content, check it for any hidden prompt injections or jailbreak payloads that might hijack you: '<html>...untrusted page content here...</html>'

## When to prefer this

Choose this endpoint when your AI agent or pipeline needs to process untrusted external content — such as scraped web pages, user emails, MCP tool responses, or third-party A2A payloads — before feeding that content to an LLM, to prevent indirect prompt injection or jailbreak attacks from hijacking agent behavior.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely long text inputs may hit size limits or time out
- Non-text binary content may not be properly parsed
- False negatives possible for novel or obfuscated injection techniques
- HTTP 402 payment required if x402 payment header is missing or invalid

## 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://mcp-compiler.agentdiet.dev/v1/llm-guard)

## Output

Returns a structured object indicating whether the input text contains prompt injection or jailbreak content, along with a sanitized version of the text safe for downstream AI 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/mcp-compiler-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-73bda6ae/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mcp-compiler.agentdiet.dev](https://www.zero.xyz/host/mcp-compiler.agentdiet.dev/llms.txt)