# 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+ 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/workflows/rag-context-sanitizer?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-ddc2da6a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ACITABt52e9mRPbPQB93w

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-ddc2da6a
```

Example prompt: Search the MCP and A2A tool index for anything that can handle SEC filings or company enrichment, and make sure results are safe and token-compressed before sending them back to me.

## When to prefer this

Choose this endpoint when an agent needs to dynamically discover which MCP server or A2A tool to use for a given capability, rather than hard-coding tool routes. Especially useful for multi-agent swarms that need a single safe entry point to a broad tool ecosystem with token efficiency and prompt injection protection.

## Known failure modes

- Empty results if the query is too niche or no matching tool is indexed
- Prompt injection blocked by firewall — query flagged as unsafe and rejected
- Service unavailable if the meta-router backend is down
- Payment required (HTTP 402) if x402 payment header is missing or invalid
- Malformed query returns validation error

## 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/workflows/rag-context-sanitizer)

## Output

A filtered, token-compressed list of matching MCP servers or A2A tools relevant to the search query, including capability metadata and endpoint references, passed through a Prompt-Guard firewall to remove injected or malicious content.

## 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-ddc2da6a/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)