# 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 injection and jailbreak attacks, returning sanitized text.

## Facts

- Endpoint: GET https://hn-pulse.agentdiet.dev/v1/mcp-injection-firewall?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-c9a54e95
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_7dNPWZ6dIv7RK1Iuk7ZKG

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-c9a54e95
```

Example prompt: Before you process this scraped web page, run it through the prompt injection firewall to check for any hidden jailbreak instructions embedded in the HTML: [paste content here].

## When to prefer this

Choose this endpoint when an AI agent needs to safely process untrusted external content — such as scraped web pages, inbound emails, MCP tool responses, or A2A payloads — before feeding that content into an LLM pipeline. It is especially valuable in agentic workflows where indirect prompt injection is a real attack vector and content provenance is unknown.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely long payloads may exceed processing limits or timeout
- Obfuscated or novel injection techniques may not be detected
- Payment failure via x402 results in 402 response blocking the scan
- Malformed HTML may cause partial sanitization

## 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/mcp-injection-firewall)

## Output

Returns a JSON object containing the sanitized version of the input text with any detected prompt injection or jailbreak payloads removed or flagged, along with detection metadata indicating whether malicious content was found.

## 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-c9a54e95/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)