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

Searches across 500+ indexed MCP servers and A2A tools using a natural-language capability query, returning compressed, firewall-filtered matching endpoints in a single connection.

## Facts

- Endpoint: GET https://preflight.agentdiet.dev/v1/swarm-router?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: preflight.agentdiet.dev
- Website: https://preflight.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/preflight-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-6debe63f
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_b3F2WYMYofF1h1HgfBqZz

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 preflight-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-6debe63f
```

Example prompt: Search the swarm router for MCP servers that can handle SEC filings or financial document retrieval — I need to find the best available tool for that capability.

## When to prefer this

Choose this endpoint when an AI agent needs to dynamically discover which MCP server or A2A tool is best suited for a given capability at runtime, especially in multi-agent swarm architectures where the right downstream tool isn't known in advance. Ideal when you want a single connection point that aggregates 500+ tools rather than maintaining individual integrations. Also useful for verifying whether a specific endpoint URL is indexed and safe before calling it.

## Known failure modes

- Empty query string returns 400 validation error
- No matching tools found for obscure capability queries returns empty result set
- Endpoint URL verification fails if URL is not in the index
- Rate limiting or payment failure (x402) blocks the request
- Prompt-Guard firewall may flag and reject 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://preflight.agentdiet.dev/v1/swarm-router)

## Output

Returns a compressed, firewall-filtered list of matching MCP servers or A2A tools ranked by relevance to the query, with metadata about each tool's capabilities, endpoint URLs, and safety status. The response uses 85% token compression to minimize LLM context consumption.

## 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/preflight-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-6debe63f/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from preflight.agentdiet.dev](https://www.zero.xyz/host/preflight.agentdiet.dev/llms.txt)