""" This example demonstrates how to set up and use an in-memory FastMCP proxy. It illustrates the pattern: 1. Create an original FastMCP server with some tools. 2. Create a proxy FastMCP server using ``FastMCP.as_proxy(original_server)``. 3. Use another Client to connect to the proxy server (in-memory) and interact with the original server's tools through the proxy. """ import asyncio from mcp.types import TextContent from fastmcp import FastMCP from fastmcp.client import Client class EchoService: """A simple service to demonstrate with""" def echo(self, message: str) -> str: return f"Original server echoes: {message}" async def main(): print("--- In-Memory FastMCP Proxy Example ---") print("This example will walk through setting up an in-memory proxy.") print("-----------------------------------------") # 1. Original Server Setup print( "\nStep 1: Setting up the Original Server (OriginalEchoServer) with an 'echo' tool..." ) original_server = FastMCP("OriginalEchoServer") original_server.add_tool(EchoService().echo) print(f" -> Original Server '{original_server.name}' created.") # 2. Proxy Server Creation print("\nStep 2: Creating the Proxy Server (InMemoryProxy)...") print( f" (Using FastMCP.as_proxy to wrap '{original_server.name}' directly)" ) proxy_server = FastMCP.as_proxy(original_server, name="InMemoryProxy") print( f" -> Proxy Server '{proxy_server.name}' created, proxying '{original_server.name}'." ) # 3. Interacting via Proxy print("\nStep 3: Using a new Client to connect to the Proxy Server and interact...") async with Client(proxy_server) as final_client: print(f" -> Successfully connected to proxy '{proxy_server.name}'.") print("\n Listing tools available via proxy...") tools = await final_client.list_tools() if tools: print(" Available Tools:") for tool in tools: print( f" - {tool.name} (Description: {tool.description or 'N/A'})" ) else: print(" No tools found via proxy.") message_to_echo = "Hello, simplified proxied world!" print(f"\n Calling 'echo' tool via proxy with message: '{message_to_echo}'") try: result = await final_client.call_tool("echo", {"message": message_to_echo}) if result and isinstance(result[0], TextContent): print(f" Result from proxied 'echo' call: '{result[0].text}'") else: print( f" Error: Unexpected result format from proxied 'echo' call: {result}" ) except Exception as e: print(f" Error calling 'echo' tool via proxy: {e}") print("\n-----------------------------------------") print("--- In-Memory Proxy Example Finished ---") if __name__ == "__main__": asyncio.run(main())