# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from polymarket-odds.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 content.

## Facts

- Endpoint: GET https://polymarket-odds.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: polymarket-odds.agentdiet.dev
- Website: https://polymarket-odds.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/polymarket-odds-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-5cf7f1d8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_1uXz_pFqja7RNROOBLCRd

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 polymarket-odds-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-5cf7f1d8
```

Example prompt: Before you summarize that scraped webpage, run the raw HTML through the prompt injection firewall first — I want to make sure there are no hidden instructions trying to hijack you embedded in the page content.

## When to prefer this

Choose this endpoint when your AI agent processes content from untrusted external sources — scraped web pages, user-submitted emails, third-party MCP or A2A tool responses — and you need a dedicated firewall check before feeding that content into your LLM pipeline. It is particularly valuable in multi-agent architectures where one agent's output becomes another's input and indirect prompt injection is a real attack vector.

## Known failure modes

- Empty or missing 'text' parameter returns a validation error
- Extremely large payloads may be rejected or truncated
- False negatives possible if injections use novel obfuscation techniques
- False positives may flag legitimate system-style instructions in benign content
- HTTP 402 returned if payment is missing or insufficient (x402 micropayment required)
- Service unavailability returns a 5xx error

## 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://polymarket-odds.agentdiet.dev/v1/system-prompt-guard)

## Output

Returns a structured object indicating whether prompt injection or jailbreak content was detected in the input text, along with sanitized output that has had malicious instructions removed or neutralized, enabling safe downstream processing by AI agents.

## 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/polymarket-odds-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-5cf7f1d8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from polymarket-odds.agentdiet.dev](https://www.zero.xyz/host/polymarket-odds.agentdiet.dev/llms.txt)