# 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 injections and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: GET https://preflight.agentdiet.dev/v1/prompt-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-c88492a8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_BpZCpSv2L802dzHeTMRYg

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-c88492a8
```

Example prompt: Before you process that scraped web page, run it through the prompt injection firewall first — check whether it contains any hidden instructions or jailbreak attempts trying to hijack you, and give me the sanitized version.

## When to prefer this

Choose this endpoint when your AI agent is about to process content from untrusted external sources — scraped web pages, user-submitted text, third-party API responses, MCP tool outputs, or incoming emails — and you need to verify the content doesn't contain adversarial prompt injections or jailbreak attempts before your agent acts on it. Prefer this over general content moderation APIs when your specific threat model is indirect prompt injection targeting LLM agents, not just toxic or harmful language.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely long payloads may be truncated or rejected
- Highly obfuscated or encoded injections may evade detection
- Non-text binary content may not be properly parsed
- Network timeout for very large HTML documents
- HTTP 402 Payment Required if x402 micropayment not included

## 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/prompt-firewall)

## Output

Returns a JSON object indicating whether the input text contains hidden prompt injection or jailbreak payloads, along with sanitized text stripped of adversarial instructions, enabling safe downstream agent 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/preflight-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-c88492a8/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)