# 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 serp-extract.agentdiet.dev, paid per call via MPP, $0.01/call, status unknown (last checked 2026-10-21).

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

## Facts

- Endpoint: GET https://serp-extract.agentdiet.dev/v1/universal-mcp-gateway?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: serp-extract.agentdiet.dev
- Website: https://serp-extract.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/serp-extract-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-dae98b62
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_c0hXK8VVVj18J_nlF8YXh

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 serp-extract-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-dae98b62
```

Example prompt: Search the MCP gateway index for tools that can handle SEC filings and company enrichment — I need to find which servers in the 500+ index support those capabilities.

## When to prefer this

Choose this endpoint when an AI agent needs to dynamically discover which MCP servers or A2A tools are available for a given capability, rather than hard-coding tool URLs. Especially useful for swarm orchestrators that need to delegate subtasks to the right tool at runtime, or when verifying whether a specific endpoint URL is valid and indexed. Prefer over manual tool registries when token efficiency and injection safety are priorities.

## Known failure modes

- Empty query string returns a validation error (minLength:1 not met)
- Query matches no indexed tools — returns empty result set
- Endpoint URL verification fails if the URL is not indexed or unreachable
- Rate limiting or payment failure (x402) blocks the request
- Prompt-Guard firewall may flag and block queries containing injection-like patterns

## 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://serp-extract.agentdiet.dev/v1/universal-mcp-gateway)

## Output

Returns a token-compressed list of matching MCP servers and A2A tool endpoints relevant to the capability query, including metadata about each tool, filtered through a Prompt-Guard firewall to prevent injection attacks. Results are compressed by ~85% compared to raw responses.

## 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/serp-extract-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-dae98b62/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from serp-extract.agentdiet.dev](https://www.zero.xyz/host/serp-extract.agentdiet.dev/llms.txt)