# 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 2026-10-23).

Searches a meta-index of 500+ MCP servers and A2A tools, returning compressed capability results with built-in prompt-injection firewall protection.

## Facts

- Endpoint: POST https://defi-yield.agentdiet.dev/v1/x402-gateway?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-23
- 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-78992826
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ofZR27T9Adl7gmZJmRozh

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-78992826 -d '<json body>'
```

Example prompt: Search the meta-index for MCP servers and A2A tools that handle SEC filings or company enrichment — I want the compressed list of what's available so I can route my agent to the right one.

## When to prefer this

Choose this endpoint when an AI agent needs to dynamically discover which MCP server or A2A tool to call for a capability it doesn't already know about, especially when token budget is constrained (85% compression helps) or when untrusted tool responses need prompt-injection screening before use. Prefer over hardcoding individual tool URLs when building swarm or orchestrator agents that need flexible routing across a broad ecosystem.

## Known failure modes

- Empty query string returns validation error
- Query matches no indexed tools — returns empty result set
- Prompt-guard firewall blocks a result flagged as unsafe injection
- Upstream MCP server unavailable — tool listed but unreachable
- Rate limit exceeded for $0.01/call tier — 429 response

## 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

Returns a compressed list of matching MCP servers and A2A tools with their capability descriptions, relevance scores, and routing metadata, with 85% token compression applied and prompt-guard filtering to flag any unsafe tool responses.

## 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-78992826/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)