# 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 a meta-index of 500+ MCP servers and A2A tools by capability query, returning compressed, firewall-filtered results for agent tool discovery and routing.

## Facts

- Endpoint: GET https://preflight.agentdiet.dev/v1/crypto-alpha-dag?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-6c27036b
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5sdCZYdSEKavUL_DkjrAb

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-6c27036b
```

Example prompt: Search the MCP tool index for any servers or A2A agents that handle 'SEC filings' and give me the best matches with compressed descriptions I can use to route my next agent call.

## 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 capability at runtime, rather than hardcoding tool references. Ideal for swarm architectures, meta-orchestrators, or any agent that needs to route to the right tool from a large pool without blowing the context window. The built-in Prompt-Guard firewall makes it preferable over manual tool registries when calling untrusted external endpoints.

## Known failure modes

- Empty or too-broad query returning no meaningful matches
- Query string missing (required parameter) returns 400 error
- Unknown or malformed endpoint URL fails validation check
- Rate limiting or 402 payment required if micropayment not settled
- Prompt-Guard firewall may flag benign queries as suspicious
- Index may not include newly registered MCP servers not yet crawled

## 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/crypto-alpha-dag)

## Output

Returns a compressed, firewall-filtered list of matching MCP servers and A2A tools relevant to the capability query, including tool names, endpoint metadata, and capability summaries at up to 85% token reduction. If an endpoint URL is submitted, returns a safety validation result from the Prompt-Guard firewall.

## 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-6c27036b/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)