# 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 email-verify.agentdiet.dev, paid per call via MPP, $0.01/call, status unknown (last checked 2026-10-23).

Searches a meta-index of 500+ MCP servers and A2A tools by capability query, returning matching endpoints with token-compressed results and Prompt-Guard firewall protection.

## Facts

- Endpoint: GET https://email-verify.agentdiet.dev/v1/mcp-gateway?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Provider: email-verify.agentdiet.dev
- Website: https://email-verify.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/email-verify-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-5de40247
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_aYfWPw2tmf-YA1uwdNdxc

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 email-verify-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-5de40247
```

Example prompt: Search the MCP tool index for up to 20 servers that support 'company enrichment' — I want to find what A2A tools or MCP endpoints are available for that capability.

## When to prefer this

Choose this endpoint when you need to dynamically discover MCP servers or A2A tools by capability at runtime, rather than hardcoding tool URLs. Especially useful for swarm architectures that need to route tasks to the right tool without prior knowledge of what's available. Prefer it over direct tool calls when you don't yet know which endpoint handles a given capability.

## Known failure modes

- Empty results if query is too specific or no matching tools are indexed
- Pagination cursor expiry if session is stale
- 402 Payment Required if x402 micropayment not fulfilled
- Query too short (minLength:1 violated) returns validation error
- Timeout if the meta-index is slow to respond
- Malformed cursor returns error or resets to first page

## 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://email-verify.agentdiet.dev/v1/mcp-gateway)

## Output

A paginated list of matching MCP servers and A2A tool records matching the capability query, including endpoint metadata, capability descriptions, and an opaque cursor for fetching the next page. Results are token-compressed (up to 85%) and filtered through a Prompt-Guard firewall.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "query"
 ],
 "properties": {
  "limit": {
   "type": "integer",
   "default": 20,
   "maximum": 100,
   "minimum": 1,
   "description": "Maximum number of items to return per page (1-100)"
  },
  "query": {
   "type": "string",
   "minLength": 1,
   "description": "Capability search query (e.g. 'context compression', 'github security', 'sec filings', 'company enrichment') or endpoint URL to verify"
  },
  "cursor": {
   "type": "string",
   "description": "Opaque pagination cursor for fetching the next page"
  }
 }
}
```

## Response schema (JSON Schema)

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

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/email-verify-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-5de40247/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from email-verify.agentdiet.dev](https://www.zero.xyz/host/email-verify.agentdiet.dev/llms.txt)