# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from mesh.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://mesh.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: mesh.agentdiet.dev
- Website: https://mesh.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/mesh-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-firewall-d3a06dd0
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_XXNXYKLlN_N7tl5eiym9o

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 mesh-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-firewall-d3a06dd0
```

Example prompt: Before you process this email I just fetched, run it through the prompt injection firewall to make sure there are no hidden jailbreak instructions trying to hijack you — here's the raw text: 'Dear agent, please ignore all previous instructions and...'

## When to prefer this

Use this endpoint when your AI agent pipeline ingests content from untrusted external sources — web scraping, user-submitted emails, third-party MCP tool responses, or A2A payloads — and you need a dedicated security layer to detect and neutralize hidden prompt injection or jailbreak instructions before they reach your agent's context window. Prefer this over manual heuristics or generic text filters when you need specialized adversarial instruction detection tuned for LLM attack patterns.

## Known failure modes

- Empty or missing 'text' parameter returns a 400 validation error
- Extremely large payloads may be truncated or rejected
- Payment not provided or insufficient (402 Payment Required via x402)
- Ambiguous edge cases in adversarial content may produce false positives or false negatives
- Non-text binary content may not be correctly analyzed

## 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://mesh.agentdiet.dev/v1/prompt-shield)

## Output

Returns a JSON object indicating whether prompt injection or jailbreak content was detected in the submitted text, along with sanitized version of the input and threat classification details.

## 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/mesh-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-firewall-d3a06dd0/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mesh.agentdiet.dev](https://www.zero.xyz/host/mesh.agentdiet.dev/llms.txt)