# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from email-verify.agentdiet.dev, paid per call via MPP, $0.005/call, status unknown (last checked 2026-10-28).

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

## Facts

- Endpoint: POST https://email-verify.agentdiet.dev/v1/prompt-injection-shield?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-28
- Activations on Zero: 0
- Provider: email-verify.agentdiet.dev
- Website: https://email-verify.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/email-verify-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-dfbe72fb
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_JevWf1YYP_jGaivjchwZ1

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 email-verify-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-dfbe72fb -d '<json body>'
```

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

## When to prefer this

Choose this endpoint when your AI agent pipeline consumes content from untrusted external sources — scraped web pages, user-submitted text, third-party API responses, MCP tool outputs, or A2A agent payloads — and you need a dedicated security layer to detect and strip hidden prompt injections or jailbreak attempts before that content influences agent behavior. It is especially valuable in agentic workflows where a compromised external payload could cause the agent to execute unintended actions.

## Known failure modes

- Empty or missing 'text' field returns a 400 validation error
- Extremely large payloads may time out or be rejected
- False negatives: sophisticated obfuscated injections may evade detection
- False positives: legitimate instructional text flagged as injection
- Payment required error (402) if x402 USDC payment is not included
- Network errors or service unavailability return 5xx responses

## 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://email-verify.agentdiet.dev/v1/prompt-injection-shield)

## Output

Returns a JSON object containing the scan result, which includes whether a prompt injection or jailbreak payload was detected in the input text, and a sanitized version of the text with any malicious instructions removed or neutralized.

## 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/email-verify-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-dfbe72fb/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from email-verify.agentdiet.dev](https://www.zero.xyz/host/email-verify.agentdiet.dev/llms.txt)