# 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/prompt-injection-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-ffb93d0d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_pOOSKhxKqyrOSynhWl8sC

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-ffb93d0d -d '<json body>'
```

Example prompt: Before you process the content from that scraped web page, run it through the prompt-injection firewall to check for any hidden adversarial instructions or jailbreak payloads embedded in the HTML.

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests content from untrusted external sources — scraped web pages, emails, MCP tool responses, or A2A payloads — and you need a dedicated security layer to detect and neutralize hidden prompt injection or jailbreak attempts before they can manipulate your agent's behavior. Prefer this over generic content filters when you specifically need adversarial LLM instruction detection rather than general content moderation.

## Known failure modes

- Empty or missing 'text' field returns a 400 validation error
- Extremely long inputs may exceed processing limits or increase latency
- Novel or highly obfuscated injection techniques may evade detection
- Non-text binary content may not be parseable
- Rate limits or payment failures (HTTP 402) if USDC balance is insufficient

## 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-injection-shield)

## Output

Returns a JSON object indicating whether a prompt injection or jailbreak payload was detected in the input text, along with sanitized text with adversarial instructions removed or flagged, enabling safe downstream processing by AI agents.

## 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-ffb93d0d/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)