# 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 2026-10-28).

Searches and discovers capabilities across 500+ indexed MCP servers and A2A tools via a single meta-router endpoint with token compression and prompt-injection firewall.

## Facts

- Endpoint: GET https://defi-yield.agentdiet.dev/v1/mesh?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-28
- 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-ae8abd77
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_ZrerB3NhicdaGUU9Zqa0h

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-ae8abd77
```

Example prompt: Search the MCP and A2A tool index for capabilities related to 'SEC filings' and return up to 20 results — I need to find which servers can handle financial document retrieval.

## When to prefer this

Choose this endpoint when an agent needs to dynamically discover which MCP servers or A2A tools are available for a given capability without hardcoding tool references. Ideal for swarm orchestrators, meta-agents, or pipelines that need to route tasks to the best available tool at runtime. Prefer this over manually curated tool lists when the ecosystem is large or evolving.

## Known failure modes

- Empty query string returns a validation error requiring minLength of 1
- Cursor from a previous session or expired pagination token returns an error or empty result
- Limit outside the 1–100 range is rejected with a parameter validation error
- Query matches no indexed tools and returns an empty results list
- Service unavailability or upstream index errors return a non-200 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/mesh)

## Output

Returns a paginated list of matching MCP server or A2A tool entries with capability descriptions, endpoint metadata, and relevance scores. Includes an opaque cursor for fetching subsequent pages and leverages 85% token-compressed representations to minimize context usage.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "query"
 ],
 "properties": {
  "limit": {
   "type": "integer",
   "default": 20,
   "maximum": 100,
   "minimum": 1,
   "description": "Maximum number of items to return per page (1-100)"
  },
  "query": {
   "type": "string",
   "minLength": 1,
   "description": "Capability search query (e.g. 'context compression', 'github security', 'sec filings', 'company enrichment') or endpoint URL to verify"
  },
  "cursor": {
   "type": "string",
   "description": "Opaque pagination cursor for fetching the next page"
  }
 }
}
```

## 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-ae8abd77/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)