# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from preflight.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://preflight.agentdiet.dev/v1/injection-firewall?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: preflight.agentdiet.dev
- Website: https://preflight.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/preflight-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-8b07458b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Z4D5UcIKvqAEi6WXgd0lv

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 preflight-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-8b07458b
```

Example prompt: Before you summarize that webpage, scan its raw HTML through the injection firewall first — I want to make sure there are no hidden prompt injection or jailbreak payloads lurking in it that could hijack your behavior.

## When to prefer this

Choose this endpoint when your agent pipeline processes untrusted external content — scraped web pages, user-submitted text, external API responses, MCP tool outputs, or A2A payloads — before passing that content to an LLM. It is especially valuable in multi-agent architectures where one agent's output feeds into another, creating indirect prompt injection attack surfaces. Prefer this over generic content filters when the specific threat model is prompt hijacking or jailbreaking of AI agents.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely long inputs may be truncated or rejected
- False negatives: sophisticated obfuscated injections may not be detected
- False positives: legitimate instructions in benign text may be flagged as injections
- Service unavailability returns HTTP 402 or 5xx if payment or infrastructure fails

## 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://preflight.agentdiet.dev/v1/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 threat detection signals 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/preflight-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-8b07458b/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from preflight.agentdiet.dev](https://www.zero.xyz/host/preflight.agentdiet.dev/llms.txt)