# 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/indirect-injection-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-a448d4c2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_W8UXK_DnAUHcpYo0TC_T5

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-a448d4c2
```

Example prompt: Before you use this web page content to answer my question, run it through the prompt-injection firewall to make sure there are no hidden instructions trying to hijack you — here's the raw HTML: '<html>... [page content] ...</html>'.

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests content from untrusted external sources — web scrapes, emails, MCP tool outputs, or A2A agent responses — and you need to sanitize that content before your LLM processes it. It is especially valuable in agentic workflows where indirect prompt injection (hidden instructions embedded in web pages or tool responses) poses a real security risk. Prefer it over generic content filters when you specifically need prompt-injection and jailbreak detection tuned for LLM agent contexts.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Very large text inputs may be truncated or rejected
- Novel or obfuscated injection techniques may evade detection
- Payment failure (x402) blocks the request if USDC balance is insufficient
- Non-text binary content may not be properly parsed or sanitized

## 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/indirect-injection-guard)

## Output

Returns a sanitized version of the input text with hidden prompt injections and jailbreak payloads detected and flagged or removed, along with detection metadata indicating whether threats were 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/mcp-compiler-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-a448d4c2/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)