# 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 token-compressed results and prompt-injection firewall protection.

## Facts

- Endpoint: GET https://defi-yield.agentdiet.dev/v1/tool-broker?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-b839c157
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_nAXIINx4jvAQa4ghjHUcr

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-b839c157
```

Example prompt: Search the agentdiet tool broker for MCP servers or A2A tools that handle 'SEC filings' — I want to find available endpoints I can plug into my research agent.

## When to prefer this

Choose this endpoint when an AI agent needs to dynamically discover and route to specialized tools at runtime without maintaining its own registry — especially when token budget is constrained (85% compression), when prompt-injection safety is required for untrusted tool responses, or when building a swarm/orchestrator that needs to delegate subtasks to the best available MCP or A2A endpoint across a broad catalog of 500+ tools.

## Known failure modes

- Empty query string returns validation error (minLength:1 required)
- No matching tools found for an obscure or overly specific query
- Upstream MCP servers temporarily unavailable, reducing index coverage
- Prompt-Guard firewall may reject queries containing suspicious injection patterns
- Payment required (HTTP 402) if x402 credit is not pre-authorized

## 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/tool-broker)

## Output

A list of matching MCP servers and A2A tools relevant to the capability query, including endpoint metadata, compressed descriptions (85% token reduction), and safety-filtered results screened by the Prompt-Guard firewall. May also verify a specific endpoint URL if provided.

## 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-b839c157/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)