# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from 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://agentdiet.dev/v1/system-prompt-guard?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: agentdiet.dev
- Website: https://agentdiet.dev
- Canonical page: https://www.zero.xyz/c/agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-firewall-e2ed75b0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_QIW247EBV3scGV8OVBpT8

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 agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-firewall-e2ed75b0
```

Example prompt: Before you process this scraped web page content, run it through the prompt-injection firewall to check for any hidden jailbreak or prompt injection attacks: [paste untrusted HTML or text here].

## When to prefer this

Choose this endpoint when your AI agent needs to safely ingest untrusted external content — such as scraped web pages, emails, third-party API responses, MCP tool outputs, or A2A payloads — before processing them, to prevent indirect prompt injection and jailbreak attacks from hijacking agent behavior.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely long payloads may exceed input limits
- Obfuscated or novel injection techniques may not be detected
- Non-text binary content may not be parseable
- Rate limiting or payment failures via x402 if 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://agentdiet.dev/v1/system-prompt-guard)

## Output

Returns a JSON object containing the sanitized version of the input text with any detected prompt injection or jailbreak payloads removed or flagged, allowing agents to safely consume the cleaned content.

## 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/agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-firewall-e2ed75b0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from agentdiet.dev](https://www.zero.xyz/host/agentdiet.dev/llms.txt)