# Universal A2A & MCP Tool Discovery, Safe-Proxy & Swarm Router

> Universal A2A & MCP Tool Discovery, Safe-Proxy & Swarm Router is a paid API for AI agents from prompt-guard.agentdiet.dev, paid per call via MPP, $0.01/call, status unknown (last checked 2026-10-21).

Searches and routes across 500+ indexed MCP servers and A2A tools via a single connection, with token compression and prompt injection firewall protection.

## Facts

- Endpoint: GET https://prompt-guard.agentdiet.dev/v1/a2a-router?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: prompt-guard.agentdiet.dev
- Website: https://prompt-guard.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/prompt-guard-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-25cc1fc2
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ameeGYq9oN4fxqrEhitQk

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 prompt-guard-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-25cc1fc2
```

Example prompt: Search the A2A and MCP tool index for anything that can handle SEC filings retrieval — I want a single compressed tool manifest I can use without juggling multiple server connections.

## When to prefer this

Choose this endpoint when an AI agent needs to dynamically discover and route to one of many MCP servers or A2A tools without maintaining individual connections to each. It is especially valuable for agent swarms needing a single meta-router with built-in token compression and prompt injection protection, rather than a raw directory or static tool list.

## Known failure modes

- Empty result set if no indexed tools match the capability query
- Rate limiting or payment required error (HTTP 402) if x402 payment not attached
- Firewall rejection if query is flagged by Prompt-Guard as a prompt injection attempt
- Timeout if upstream MCP server index is unavailable
- Invalid query format if the query field is missing or empty

## How this service works

Single-connection meta-router indexing 500+ MCP servers & A2A tools with 85% token compression and Prompt-Guard firewall. (Live x402 v2, IETF MPP & MCP endpoint at https://prompt-guard.agentdiet.dev/v1/a2a-router)

## Output

A compressed manifest (up to 85% token reduction) listing matching MCP servers or A2A tools relevant to the query, with routing metadata and Prompt-Guard firewall filtering applied. May also return compliance status if an endpoint URL is submitted for verification.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "query"
 ],
 "properties": {
  "query": {
   "type": "string",
   "minLength": 1,
   "description": "Capability search query (e.g. 'context compression', 'github security', 'sec filings', 'company enrichment') or endpoint URL to verify"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/prompt-guard-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-25cc1fc2/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from prompt-guard.agentdiet.dev](https://www.zero.xyz/host/prompt-guard.agentdiet.dev/llms.txt)