# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from whale-momentum.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 injection and jailbreak attacks, returning sanitized output.

## Facts

- Endpoint: GET https://whale-momentum.agentdiet.dev/v1/system-prompt-guard?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: whale-momentum.agentdiet.dev
- Website: https://whale-momentum.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/whale-momentum-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-4ef1c66c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_fdF5bhMkSEM5azew9ogKc

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 whale-momentum-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-4ef1c66c
```

Example prompt: Before you process this scraped web page content, run it through the prompt-injection firewall to check for hidden instructions trying to hijack you — here's the raw text: [paste content here].

## When to prefer this

Choose this endpoint when your AI agent needs to safely process external, untrusted content — such as scraped web pages, third-party API responses, emails, or MCP/A2A tool outputs — before incorporating that content into its reasoning context. It is especially valuable in multi-agent pipelines where one agent's output feeds another, creating indirect prompt injection risk. Prefer this over generic content filters when you specifically need prompt injection and jailbreak detection rather than general content moderation.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Very large payloads may timeout or be truncated
- False negatives: novel or obfuscated injections may not be detected
- False positives: legitimate instructions in the text may be flagged as injections
- Payment not fulfilled returns HTTP 402 requiring x402 micropayment
- Service unavailability returns 5xx 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://whale-momentum.agentdiet.dev/v1/system-prompt-guard)

## Output

Returns a sanitized version of the input text with detected prompt injection or jailbreak payloads identified and removed or flagged, along with a structured assessment of any threats 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/whale-momentum-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-4ef1c66c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from whale-momentum.agentdiet.dev](https://www.zero.xyz/host/whale-momentum.agentdiet.dev/llms.txt)