# 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 content.

## Facts

- Endpoint: GET https://mcp-compiler.agentdiet.dev/v1/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-2be101c9
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_INEyd4l0WKxpWek47dBpT

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-2be101c9
```

Example prompt: Before you process this web page I just scraped, run it through the prompt injection firewall to check for any hidden jailbreak instructions or adversarial prompts embedded in the HTML.

## When to prefer this

Choose this endpoint when your agent pipeline ingests text from untrusted external sources — web scrapes, emails, MCP tool responses, or A2A payloads — and you need a dedicated firewall layer to detect and strip indirect prompt injection or jailbreak attempts before the content reaches your LLM. It is purpose-built for A2A and MCP security contexts, making it more appropriate than general-purpose content filters when the threat model specifically involves adversarial prompt manipulation targeting AI agents.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely long inputs may be truncated or rejected
- False negatives: novel or obfuscated injection techniques may not be detected
- Service unavailable or payment required (HTTP 402) if micropayment not completed
- Ambiguous HTML encoding may cause inconsistent sanitization results

## 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/guard)

## Output

Returns an object containing the scan result, indicating whether the input contains hidden prompt injection or jailbreak payloads, along with sanitized text safe for downstream 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/mcp-compiler-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-2be101c9/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)