# 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 2026-10-23).

Scans untrusted text, HTML, emails, MCP responses, or A2A payloads for hidden prompt injections and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: POST https://preflight.agentdiet.dev/v1/tool-poisoning-shield?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-23
- 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-9b901945
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_HOceVObhzWCHH1VwA245J

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-9b901945 -d '<json body>'
```

Example prompt: Before you process this scraped web page, run it through the prompt-injection firewall to check for any hidden instructions or jailbreak payloads embedded in the content — here's the raw HTML text to scan.

## When to prefer this

Use this endpoint whenever an 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 email bodies — especially in agentic pipelines where injected instructions could hijack agent behavior. Prefer this over manual inspection when operating at scale or when the source is adversarially motivated.

## Known failure modes

- Empty or whitespace-only text input returns a validation error
- Extremely long payloads may hit size limits or timeout
- Novel or obfuscated injection techniques may not be detected
- Non-text binary content cannot be scanned
- Service unavailable if payment (x402) is not properly handled

## 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/tool-poisoning-shield)

## Output

A JSON object indicating whether the input contains detected prompt injection or jailbreak content, along with a sanitized version of the text safe for downstream LLM or agent consumption.

## 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-9b901945/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)