jcorpac directory-federation
Purpose
Traditional MCP "routers" act as a middleman that receives a tool execution request, proxies it to the subordinate server, and proxies the result back. This creates execution bottlenecks, limits streaming potential, and drastically increases attack surface.
Federating the router into a pure Directory shifts the execution back to the client.
Usage
Instead of wrapping subordinate tools inside your router, expose a single meta-tool that returns connection strings to the agents.
from mcp.server.fastmcp import FastMCP
mcp = FastMCP("Directory Service")
@mcp.tool()
def search_available_tools_and_servers(query: str) -> list[dict]:
"""Allows the agent to query for tools and get their direct connection details."""
# Database logic returning SSE URLs or Stdio command definitions
return [
{
"tool_name": "search_wikipedia",
"server_transport": "stdio",
"command": "docker run -i --rm mcp/wikipedia-mcp"
}
]
When an agent needs a tool, it first queries the directory, gets the connection string, instantiates a direct MCP client to the target server, and runs the tool natively. It is a highly robust and scalable architecture.
Resources
- MCP Specification (Transports)