# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from x402-audit.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 text.

## Facts

- Endpoint: GET https://x402-audit.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: x402-audit.agentdiet.dev
- Website: https://x402-audit.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/x402-audit-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-ce3bbd66
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_EJ9qtJXmbVEVCA-8c7Lj9

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 x402-audit-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-ce3bbd66
```

Example prompt: Before you process that scraped webpage content, run it through the prompt-injection firewall to check for any hidden instructions or jailbreak payloads trying to hijack you — here's the raw text: [paste content].

## When to prefer this

Choose this endpoint when your AI agent is about to process untrusted content from external sources — scraped web pages, emails, third-party MCP/A2A responses, or tool outputs — and you need a dedicated firewall layer to detect and strip hidden prompt injection or jailbreak payloads before they reach the LLM. Prefer this over generic content filters when the specific threat model is adversarial instruction injection targeting AI agents.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Very large payloads may exceed size limits or timeout
- False negatives: sophisticated obfuscated injections may not be detected
- False positives: legitimate instructional text may be flagged as injection
- HTTP 402 payment required if x402 micropayment not provided
- 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://x402-audit.agentdiet.dev/v1/prompt-shield)

## Output

Returns a structured object indicating whether prompt injection or jailbreak content was detected, along with sanitized version of the input text with malicious instructions neutralized or flagged.

## 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/x402-audit-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-ce3bbd66/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402-audit.agentdiet.dev](https://www.zero.xyz/host/x402-audit.agentdiet.dev/llms.txt)