# 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 and routes across 500+ indexed MCP servers and A2A tools via a single meta-router endpoint with token compression and prompt firewall protection

## Facts

- Endpoint: GET https://serp-extract.agentdiet.dev/v1/x402-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-56e20f1a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_VxfAKuj7SlxdQbsaHzUuw

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-56e20f1a
```

Example prompt: Search the MCP tool index for any servers or A2A agents that handle SEC filings or financial document extraction — I want to find the best tool to call for that capability.

## When to prefer this

Use this endpoint when an AI agent needs to discover which MCP server or A2A tool to call for a given capability, rather than calling a known tool directly. Ideal for dynamic agent orchestration, swarm routing, or when the right downstream tool is unknown at design time. Prefer over manual tool registries when you need compressed metadata and a prompt-firewall safety layer.

## Known failure modes

- Empty or too-broad query returns too many low-relevance results
- Unknown or niche capability not indexed returns no matches
- Endpoint URL verification query returns timeout if target is unreachable
- Malformed query string returns 400 validation error
- Payment not settled causes 402 response blocking access

## 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/x402-gateway)

## Output

Returns a list of matching MCP servers or A2A tools from the 500+ indexed catalog, including endpoint URLs, capability descriptions, and compressed metadata. May include routing recommendations, compliance scores, or prompt-firewall status for discovered endpoints.

## 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-56e20f1a/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)