# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from prompt-guard.agentdiet.dev, paid per call via MPP, $0.005000/call, status unknown (last checked 2026-10-23).

Scans untrusted text, HTML, MCP responses, or A2A payloads for hidden prompt injections and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: GET https://prompt-guard.agentdiet.dev/?utm_source=zero.xyz
- Price: $0.005000/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Provider: prompt-guard.agentdiet.dev
- Website: https://prompt-guard.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/prompt-guard-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-951f9587
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fLxh1pqjOdbX0F72W45PR

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 prompt-guard-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-951f9587
```

Example prompt: Before you process this scraped webpage content, run it through the prompt-injection firewall to check for any hidden jailbreak instructions or indirect prompt injections: '<html>...page content here...</html>'

## When to prefer this

Choose this endpoint when your AI agent needs to process untrusted external content — scraped web pages, emails, MCP/A2A tool responses — before passing it to an LLM, and you need a dedicated firewall layer that specifically detects indirect prompt injections and jailbreak payloads rather than general content moderation. Particularly valuable in agentic pipelines where tool outputs from third-party sources could be weaponized.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely long payloads may be truncated or rejected
- False negatives possible for novel or obfuscated injection techniques
- Rate limiting or payment failures (HTTP 402) if x402 payment not provided
- Non-text binary content may not be properly analyzed

## 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://prompt-guard.agentdiet.dev/)

## Output

Returns an object containing the sanitized version of the input text with prompt injections removed or flagged, along with detection metadata indicating whether injection attempts were found and details about the identified threats.

## 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"
  },
  "limit": {
   "type": "integer",
   "default": 20,
   "maximum": 100,
   "minimum": 1,
   "description": "Maximum number of items to return per page (1-100)"
  },
  "cursor": {
   "type": "string",
   "description": "Opaque pagination cursor for fetching the next page"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/prompt-guard-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-951f9587/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from prompt-guard.agentdiet.dev](https://www.zero.xyz/host/prompt-guard.agentdiet.dev/llms.txt)