# 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 2026-10-21).

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

## Facts

- Endpoint: GET https://serp-extract.agentdiet.dev/v1/prompt-shield?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- 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-6f0477cb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_q-Tf93Qtqp3EqLmQeSroU

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-6f0477cb
```

Example prompt: Before you process that web page content I just fetched, can you run it through the prompt-injection firewall to check for any hidden adversarial instructions or jailbreak payloads embedded in the text?

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests content from untrusted external sources — scraped web pages, third-party API responses, MCP tool outputs, user emails, or A2A payloads — and you need to sanitize that content before passing it to an LLM. It is specifically designed for agentic architectures where indirect prompt injection is a real attack vector, making it more suitable than generic content filters that are not tuned for adversarial LLM prompt patterns.

## Known failure modes

- Missing required 'text' parameter returns an error
- Empty string input rejected due to minLength:1 constraint
- Very large payloads may time out or be truncated
- Highly obfuscated injections using encoding tricks may evade detection
- Non-UTF-8 or binary content may cause parse errors

## 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-shield)

## Output

Returns a structured object indicating whether prompt injection or jailbreak payloads were detected in the submitted text, along with a sanitized version of the input 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"
  },
  "limit": {
   "type": "integer",
   "default": 20,
   "maximum": 100,
   "minimum": 1,
   "description": "Maximum number of items to return per page (1-100)"
  },
  "cursor": {
   "type": "string",
   "description": "Opaque pagination cursor for fetching the next page"
  }
 }
}
```

## 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-6f0477cb/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)