# 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 defi-yield.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 85% token-compressed results and prompt-injection protection.

## Facts

- Endpoint: GET https://defi-yield.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: defi-yield.agentdiet.dev
- Website: https://defi-yield.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/defi-yield-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-f9291e88
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_0llXpF2PDKTXg0lla9VN8

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 defi-yield-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-f9291e88
```

Example prompt: Search the MCP tool index for servers that can handle 'SEC filings' — I need to find available A2A endpoints for that capability so I can route my agent's next call.

## 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 at runtime, rather than hard-coding tool lists. Especially useful for swarm architectures where agents must self-route to the right tool, or when you want a single safe-proxy connection with built-in prompt-injection protection instead of connecting directly to untrusted MCP servers.

## Known failure modes

- Empty or vague query returns zero or low-quality matches
- Queried endpoint URL not in the 500+ server index returns no match
- Payment not received (x402 402 response) blocks result delivery
- Prompt-guard firewall flags the query itself as suspicious and rejects it
- Index may not reflect newly added MCP servers if 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://defi-yield.agentdiet.dev/v1/x402-gateway)

## Output

A JSON object listing matching MCP servers and A2A tools ranked by relevance, with compressed metadata descriptions, capability tags, endpoint URLs, and prompt-guard firewall status — all optimized to minimize token usage in the agent context window.

## 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/defi-yield-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-proxy-f9291e88/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from defi-yield.agentdiet.dev](https://www.zero.xyz/host/defi-yield.agentdiet.dev/llms.txt)