# 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 mcp-compiler.agentdiet.dev, paid per call via MPP, $0.01/call, status unknown (last checked 2026-10-21).

Searches an index of 500+ MCP servers and A2A tools by capability query, returning compressed, safe-proxied tool metadata with prompt-injection firewall protection.

## Facts

- Endpoint: GET https://mcp-compiler.agentdiet.dev/v1/b2a-router?utm_source=zero.xyz
- Price: $0.01/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-21
- Activations on Zero: 0
- Provider: mcp-compiler.agentdiet.dev
- Website: https://mcp-compiler.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/mcp-compiler-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-743e52e8
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_mj-Qu4FyXNpFDNfl6gQh_

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 mcp-compiler-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-743e52e8
```

Example prompt: Search the MCP and A2A tool index for capability 'SEC filings' — I want to find available tools I can wire into my agent pipeline for pulling company financial data.

## When to prefer this

Use this endpoint when an AI agent needs to dynamically discover which MCP servers or A2A tools support a given capability without maintaining its own tool registry. Prefer it over hardcoded tool lists when building swarm agents that need to route tasks to the best available tool, or when you want a Prompt-Guard firewall sanitizing third-party tool responses before they reach your agent context.

## Known failure modes

- Empty or too-broad query returns no useful results
- Queried URL not found in index returns empty or null match
- Rate limiting or payment failure (x402) blocks the request
- Index may not reflect newly added or removed MCP servers in real time
- Overly niche queries may return zero results if the capability is not indexed

## 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://mcp-compiler.agentdiet.dev/v1/b2a-router)

## Output

Returns a compressed (up to 85% token reduction) list of matching MCP servers or A2A tools with their capabilities, endpoints, and safety status, filtered through a Prompt-Guard firewall to strip malicious payloads before delivery to the agent.

## 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/mcp-compiler-agentdiet-dev-universal-a2a-mcp-tool-discovery-safe-743e52e8/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from mcp-compiler.agentdiet.dev](https://www.zero.xyz/host/mcp-compiler.agentdiet.dev/llms.txt)