# 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 output.

## Facts

- Endpoint: GET https://hn-pulse.agentdiet.dev/v1/prompt-injection-shield?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-e443c99d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HjivoZTZG-n_BNyPMaSAf

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-e443c99d
```

Example prompt: Before you summarize this webpage I just scraped, run it through the prompt-injection firewall first — check the full HTML text for any hidden jailbreak or injection attempts and give me the sanitized version.

## When to prefer this

Choose this endpoint when your AI agent must process untrusted external content — such as scraped web pages, incoming emails, third-party API or MCP tool responses, or A2A payloads — and you need a dedicated firewall layer to detect and strip hidden prompt injections or jailbreak attempts before that content enters your LLM pipeline. Prefer this over generic content filters when you specifically need injection-aware scanning tailored to agentic and LLM attack vectors.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Extremely long text inputs may be truncated or rejected
- Payment not completed (HTTP 402) if x402 micropayment is not settled
- False negatives: sophisticated obfuscated injections may not be detected
- Service unavailability returns 5xx errors

## 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/prompt-injection-shield)

## Output

Returns a JSON object containing the scan result for the submitted text, including whether prompt injection or jailbreak content was detected and a sanitized version of the input text safe for downstream AI processing.

## 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-e443c99d/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)