# 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 injection and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: GET https://mcp-compiler.agentdiet.dev/v1/mcp-injection-firewall?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-10a9d634
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Iu-1vbnWg-vW7G0IUDoQx

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-10a9d634
```

Example prompt: Before you process that scraped webpage, run it through the injection firewall first — I want to make sure there are no hidden prompt injection or jailbreak instructions embedded in the HTML that could hijack you.

## When to prefer this

Choose this endpoint when your AI agent processes untrusted external content — web scrapes, emails, MCP tool outputs, or A2A payloads — and you need a dedicated security layer to catch indirect prompt injection or jailbreak attempts before that content influences downstream LLM behavior. It is especially valuable in autonomous agent pipelines where the agent cannot manually review every external input.

## Known failure modes

- Empty or whitespace-only text input returns a validation error (minLength:1 not met)
- Very long payloads may time out or be truncated
- False negatives: sophisticated obfuscated injections may evade detection
- False positives: legitimate AI-related instructions in content flagged as injections
- Payment failure (HTTP 402) if x402 micropayment is not provided
- Malformed response schema if upstream firewall engine is unavailable

## 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/mcp-injection-firewall)

## Output

Returns a structured object containing the sanitized version of the input text with any detected prompt injection or jailbreak payloads removed or flagged, along with threat detection metadata.

## 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-10a9d634/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)