# 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/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-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-21841b22
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HCKKGyrIQmoprd7Fkh6pF

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-21841b22
```

Example prompt: Before you process that webpage I just scraped, run it through the prompt injection firewall to check for any hidden instructions or jailbreak payloads embedded in the text.

## When to prefer this

Use this endpoint whenever an AI agent is about to consume content from an untrusted external source — scraped web pages, emails, third-party API responses, MCP tool outputs, or A2A payloads — and you need to ensure that content does not contain hidden adversarial instructions designed to hijack or redirect the agent. Prefer this over generic content filters when your specific threat model is prompt injection and jailbreaking of LLM-based agents.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely long payloads may be truncated or time out
- Obfuscated or novel injection techniques may evade detection
- Non-text binary content may not be parseable
- Payment failure (402) if x402 USDC balance is insufficient

## 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/indirect-injection-guard)

## Output

Returns a structured object containing the scan result: whether a prompt injection or jailbreak payload was detected, and a sanitized version of the input text with any malicious instructions removed or flagged.

## 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-21841b22/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)