# 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 2026-10-23).

Searches and discovers 500+ MCP servers and A2A tools by capability query, returning token-compressed results with Prompt-Guard firewall protection.

## Facts

- Endpoint: GET https://serp-extract.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: 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-f6b71f79
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_USHZjMUB_KfgLy3SGeErl

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-f6b71f79
```

Example prompt: Search the MCP tool index for servers that can handle 'context compression' and return the top 10 results — I want to find the best agent-compatible tools for shrinking token usage in my pipeline.

## When to prefer this

Choose this endpoint when an AI agent or orchestrator needs to dynamically discover MCP-compatible or A2A-compatible tools by capability at runtime, rather than maintaining a static tool registry. Especially useful for swarm architectures that need to route tasks to the best available tool from a large index of 500+ servers, with built-in token compression and prompt injection protection.

## Known failure modes

- Empty results if the query string is too vague or no tools match
- Pagination errors if an invalid or expired cursor is supplied
- Rate limiting or 402 payment required if the per-call micropayment has not been processed
- Timeout if the meta-router is indexing or unreachable
- Query too short (minLength:1 violation) returns a 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://serp-extract.agentdiet.dev/v1/mcp-gateway)

## Output

A paginated JSON object containing matching MCP server and A2A tool records ranked by relevance to the query, with token-compressed metadata and pagination cursor for fetching additional pages. Results may include tool names, descriptions, capability tags, and endpoint URLs, 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/serp-extract-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-f6b71f79/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)