Update example servers to use mcp.server.lowlevel

Author: dsp-ant

examples/servers/simple-prompt/mcp_simple_prompt/server.py

@@ -1,7 +1,7 @@
 import anyio
 import click
 import mcp.types as types
-from mcp.server import Server
+from mcp.server.lowlevel import Server  # Using lowlevel API as mcp.server is deprecated
 
 
 def create_messages(

examples/servers/simple-resource/mcp_simple_resource/server.py

@@ -1,7 +1,8 @@
 import anyio
 import click
 import mcp.types as types
-from mcp.server import AnyUrl, Server
+from pydantic import AnyUrl
+from mcp.server.lowlevel import Server
 
 SAMPLE_RESOURCES = {
     "greeting": "Hello! This is a sample text resource.",

examples/servers/simple-tool/mcp_simple_tool/server.py

@@ -2,7 +2,7 @@
 import click
 import httpx
 import mcp.types as types
-from mcp.server import Server
+from mcp.server.lowlevel import Server  # Using lowlevel API as mcp.server is deprecated
 
 
 async def fetch_website(