# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from mcp-security.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 attacks, returning sanitized output.

## Facts

- Endpoint: GET https://mcp-security.agentdiet.dev/v1/llm-jailbreak-defense?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: mcp-security.agentdiet.dev
- Website: https://mcp-security.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/mcp-security-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-04ba0838
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nl3AWFxjAEkS4xgq48P9O

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-security-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-04ba0838
```

Example prompt: Before you process this scraped webpage content, run it through the prompt injection firewall to check for any hidden jailbreak instructions or malicious overrides embedded in the HTML, then give me the sanitized version.

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests content from untrusted external sources — web pages, emails, third-party API responses, MCP tool outputs, or A2A payloads — and you need a dedicated security layer to detect and strip hidden prompt injection or jailbreak instructions before they reach your LLM context. Especially valuable in autonomous agent architectures where compromised tool outputs could cascade into harmful actions.

## Known failure modes

- Missing required 'text' parameter returns a 400 validation error
- Empty string input rejected due to minLength:1 constraint
- Very large payloads may be truncated or time out
- Novel or obfuscated injection techniques may evade detection
- Non-text binary content may not be properly parsed
- Payment not processed (402) blocks the request

## 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-security.agentdiet.dev/v1/llm-jailbreak-defense)

## Output

Returns a JSON object containing the scan result, indicating whether prompt injection or jailbreak content was detected, along with sanitized/cleaned 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-security-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-04ba0838/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mcp-security.agentdiet.dev](https://www.zero.xyz/host/mcp-security.agentdiet.dev/llms.txt)