# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from x402broker.com, 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://x402broker.com/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: x402broker.com
- Website: https://x402broker.com
- Canonical page: https://www.zero.xyz/c/x402broker-com-a2a-indirect-prompt-injection-jailbreak-firewall-f2cfed89
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_y0ofnPduXQfRIwtgGOSBU

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 x402broker-com-a2a-indirect-prompt-injection-jailbreak-firewall-f2cfed89 -d '<json body>'
```

Example prompt: Before you process this scraped web page, run it through the prompt injection firewall first — here's the raw HTML: [paste content] — I want to make sure there are no hidden instructions trying to hijack your behavior.

## When to prefer this

Choose this endpoint when your AI agent pipeline ingests content from untrusted external sources — web scraping, email ingestion, third-party API responses, or user-submitted text — and you need a dedicated security layer to detect and neutralize indirect prompt injection or jailbreak payloads before they reach your LLM. Prefer this over generic content filters when specifically protecting agent-to-agent (A2A) or MCP tool call chains from adversarial manipulation.

## Known failure modes

- Empty or missing 'text' field returns a 400 validation error
- Extremely large payloads may time out or be rejected
- Ambiguous or obfuscated injections using novel encoding may not be detected
- Non-text binary content may fail to parse correctly
- Payment failure via x402 returns HTTP 402 before scan is performed

## 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://x402broker.com/v1/prompt-injection-shield)

## Output

Returns a sanitized version of the input text with prompt injection payloads neutralized or flagged, along with detection metadata indicating whether injections were found and what type of threat was identified.

## 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/x402broker-com-a2a-indirect-prompt-injection-jailbreak-firewall-f2cfed89/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from x402broker.com](https://www.zero.xyz/host/x402broker.com/llms.txt)