# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from defi-yield.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://defi-yield.agentdiet.dev/v1/prompt-injection-shield?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: defi-yield.agentdiet.dev
- Website: https://defi-yield.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/defi-yield-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-093ba455
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NLKpOivvYZinG_HqDlDs1

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 defi-yield-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-093ba455
```

Example prompt: Before you process this scraped webpage content, can you run it through the prompt-injection firewall to check for any hidden instructions or jailbreak attempts and give me the sanitized version?

## When to prefer this

Use this endpoint whenever your agent pipeline ingests content from untrusted external sources — web pages, emails, third-party API responses, MCP tool outputs, or A2A messages — before passing that content to an LLM. It is especially valuable in agentic workflows where indirect prompt injection could cause the agent to execute unintended actions. Prefer this over generic text-cleaning tools when the threat model specifically involves adversarial LLM prompt manipulation rather than simple spam or malware.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Extremely long inputs may be truncated or rejected
- Payment not provided or invalid x402 credentials result in a 402 Payment Required response
- Network timeouts if the scanning service is overloaded
- False negatives — sophisticated injections may not always be caught
- Ambiguous or borderline content may produce inconsistent sanitization results

## 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://defi-yield.agentdiet.dev/v1/prompt-injection-shield)

## Output

Returns a JSON object containing the sanitized version of the submitted text with any detected prompt injection or jailbreak payloads removed or flagged, allowing the calling agent to safely process the cleaned content downstream.

## 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/defi-yield-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-093ba455/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from defi-yield.agentdiet.dev](https://www.zero.xyz/host/defi-yield.agentdiet.dev/llms.txt)