# 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 an index of 500+ MCP servers and A2A tools by capability query and returns compressed, firewall-filtered matching endpoints in a single connection

## Facts

- Endpoint: GET https://prompt-guard.agentdiet.dev/v1/bundle-execute?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-ac557110
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VIv-LvFzsC5DSuXmWJ4eW

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-ac557110
```

Example prompt: Search the MCP tool index for servers that handle 'github security' — I want to find the best-matching A2A endpoints I can route my agent through, with prompt firewall protection enabled.

## When to prefer this

Choose this endpoint when an agent needs to dynamically discover which MCP servers or A2A tools support a given capability without maintaining its own registry, especially when prompt safety filtering (Prompt-Guard firewall) and token-efficient responses are priorities. Useful for swarm orchestration scenarios where a single connection must resolve tool routing across hundreds of providers.

## Known failure modes

- Missing required 'query' parameter returns an error
- Query too short or empty (minLength:1 violation) rejected
- No matching tools found for obscure or highly specific queries
- Firewall blocks queries flagged as prompt injection attempts
- HTTP 402 payment required if prepaid quota is exhausted
- Upstream MCP index unavailability causes partial or empty results

## 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/bundle-execute)

## Output

Returns a compressed list of matching MCP servers and A2A tools relevant to the query, with up to 85% token compression applied and Prompt-Guard firewall filtering, including tool metadata such as endpoint URLs, capability descriptions, and compliance signals.

## 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-ac557110/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)