# 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 injection and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: GET https://polymarket-odds.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: 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-40dd9e5e
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_NNVZSfUk8zRP595gqDUVl

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-40dd9e5e
```

Example prompt: Before processing this scraped webpage content, run it through the prompt-injection firewall to check for hidden jailbreak instructions and give me the sanitized version: '<html>...attacker content...</html>'

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests content from untrusted external sources — such as scraped web pages, third-party API responses, MCP tool outputs, A2A agent payloads, or user-submitted emails — and you need a lightweight, per-call firewall check before passing that content downstream to an LLM. Prefer this over general-purpose content moderation APIs when the specific threat model is indirect prompt injection and jailbreak payloads embedded in otherwise legitimate-looking text.

## Known failure modes

- Missing required 'text' parameter returns a 400 error
- Empty string input rejected due to minLength:1 constraint
- Payment not fulfilled triggers HTTP 402 response requiring x402 USDC payment
- Overly long input text may be truncated or rejected
- False negatives possible for novel or obfuscated injection techniques
- 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://polymarket-odds.agentdiet.dev/v1/prompt-shield)

## Output

Returns a JSON object containing the scan result for the submitted text, including whether prompt injection or jailbreak content was detected and a sanitized version of the input text with adversarial instructions removed 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/polymarket-odds-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-40dd9e5e/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)