# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from serp-extract.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://serp-extract.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: serp-extract.agentdiet.dev
- Website: https://serp-extract.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/serp-extract-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-73104b1a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_puLnUguGE4pniSCBPNypY

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 serp-extract-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-73104b1a -d '<json body>'
```

Example prompt: Before I process this scraped web page content in my agent pipeline, can you scan it for any hidden prompt injection or jailbreak instructions and return the sanitized version?

## When to prefer this

Choose this endpoint when your agent pipeline ingests untrusted external content — web pages, emails, tool responses, or third-party A2A payloads — and you need to detect and strip hidden prompt injection or jailbreak instructions before passing content to an LLM. It is purpose-built for agent security in A2A and MCP ecosystems, making it preferable to generic content filters that lack LLM-adversarial awareness.

## Known failure modes

- Empty or missing 'text' field returns a 400 validation error
- Extremely long payloads may time out or exceed size limits
- False negatives possible if injection technique is novel or obfuscated
- False positives may sanitize legitimate instruction-like text
- Network or upstream service errors return 5xx responses
- Payment required (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://serp-extract.agentdiet.dev/v1/prompt-injection-shield)

## Output

Returns a JSON object containing the sanitized version of the input text with any detected prompt injection or jailbreak content identified and removed or flagged, along with detection metadata indicating whether a threat 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/serp-extract-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-73104b1a/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from serp-extract.agentdiet.dev](https://www.zero.xyz/host/serp-extract.agentdiet.dev/llms.txt)