# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from hn-pulse.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 injections and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: GET https://hn-pulse.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: hn-pulse.agentdiet.dev
- Website: https://hn-pulse.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/hn-pulse-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-firewall-6888c87b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_8Yt8OTzRsezjIZ8KZmkZm

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 hn-pulse-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-firewall-6888c87b
```

Example prompt: Before you process this webpage content I just scraped, run it through the jailbreak firewall to check for hidden prompt injections and give me the sanitized version: '[raw HTML or text here]'

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests untrusted external content — scraped web pages, user emails, third-party API responses, MCP tool outputs, or A2A payloads — before passing that content to an LLM. It is specifically designed for the indirect prompt injection threat model where attackers embed hidden instructions in content that your agent will read, making it distinct from general content moderation or spam filters.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Very large payloads may time out or be truncated
- Sophisticated obfuscated injections may evade detection (false negatives)
- Payment not fulfilled returns HTTP 402 requiring x402 USDC settlement
- Ambiguous borderline content may produce inconsistent classification

## 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://hn-pulse.agentdiet.dev/v1/llm-jailbreak-defense)

## Output

Returns a structured object indicating whether prompt injection or jailbreak content was detected in the input, along with a sanitized version of the text with malicious instructions removed or neutralized.

## 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/hn-pulse-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-firewall-6888c87b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from hn-pulse.agentdiet.dev](https://www.zero.xyz/host/hn-pulse.agentdiet.dev/llms.txt)