Merge pull request #825 from realpython/update-mcp-client-sdk-v2

Update python-mcp-client sample code for MCP SDK 2.x

Author: realpython-bot

python-mcp-client/source-code-final/README.md

@@ -50,7 +50,7 @@ $ uv run python -m mcp_client <path/to/mcp/server.py> --chat
 ```console
 $ uv run python -m mcp_client mcp_server/mcp_server.py --chat
 
-MCP Client Started!
+MCP Client's Chat Started!
 Type your queries or 'quit' to exit.
 
 You: Greet Pythonista
@@ -68,14 +68,14 @@ You:
 
 The project includes, `mcp_server.py`, which is a minimal MCP server that provides:
 
-- A sample tool that says hello
+- A sample `echo` tool that echoes back a message
 - Sample prompts and resources
 
 You can use this server to test the client's functionalities.
 
 ## Requirements
 
-- Python >= 3.13
+- Python >= 3.14
 - The MCP Python SDK and OpenAI Python SDK
 - An OpenAI API key
 - An MCP server to connect to

python-mcp-client/source-code-final/mcp_client/chat.py

@@ -11,6 +11,8 @@ async def run_chat(handler) -> None:
                 break
 
             print("\n" + await handler.process_query(query))
+        except EOFError:
+            break
         except Exception as e:
             print(f"\nError: {str(e)}")
 

python-mcp-client/source-code-final/mcp_client/handlers.py

@@ -4,7 +4,7 @@
 from mcp import ClientSession
 from openai import OpenAI
 
-MODEL = "gpt-4o-mini"
+MODEL = "gpt-5.4-mini"
 MAX_TOKENS = 1000
 
 
@@ -25,7 +25,7 @@ async def process_query(self, query: str) -> str:
         messages = [{"role": "user", "content": query}]
         initial_response = self.openai.chat.completions.create(
             model=MODEL,
-            max_tokens=MAX_TOKENS,
+            max_completion_tokens=MAX_TOKENS,
             messages=messages,
             tools=await self._get_tools(),
         )
@@ -55,7 +55,7 @@ async def process_query(self, query: str) -> str:
             # Get final Model's response after tool execution
             final_response = self.openai.chat.completions.create(
                 model=MODEL,
-                max_tokens=MAX_TOKENS,
+                max_completion_tokens=MAX_TOKENS,
                 messages=messages,
             )
 
@@ -75,7 +75,7 @@ async def _get_tools(self) -> list:
                     "description": tool.description or "No description",
                     "parameters": getattr(
                         tool,
-                        "inputSchema",
+                        "input_schema",
                         {"type": "object", "properties": {}},
                     ),
                 },

python-mcp-client/source-code-final/mcp_client/mcp_client.py

@@ -1,3 +1,4 @@
+import os
 import sys
 from contextlib import AsyncExitStack
 from typing import Any, Awaitable, Callable, ClassVar, Self
@@ -36,13 +37,11 @@ async def _connect_to_server(self) -> ClientSession:
             read, write = await self.exit_stack.enter_async_context(
                 stdio_client(
                     server=StdioServerParameters(
-                        command="sh",
-                        args=[
-                            "-c",
-                            f"{sys.executable} {self.server_path} 2>/dev/null",
-                        ],
+                        command=sys.executable,
+                        args=[self.server_path],
                         env=None,
-                    )
+                    ),
+                    errlog=open(os.devnull, "w"),
                 )
             )
             client_session = await self.exit_stack.enter_async_context(

python-mcp-client/source-code-final/mcp_server/mcp_server.py

@@ -1,6 +1,8 @@
-from mcp.server.fastmcp import FastMCP
+from pathlib import Path
 
-mcp = FastMCP("mcp_server")
+from mcp.server.mcpserver import MCPServer
+
+mcp = MCPServer("mcp_server")
 
 
 @mcp.tool()
@@ -12,13 +14,14 @@ async def echo(message: str) -> str:
 @mcp.prompt()
 async def greeting_prompt(name: str) -> str:
     """A simple greeting prompt."""
-    return f"Great {name} kindly."
+    return f"Greet {name} kindly."
 
 
 @mcp.resource("file://./greeting.txt")
 def greeting_file() -> str:
     """The greeting text file."""
-    with open("greeting.txt", "r", encoding="utf-8") as file:
+    path = Path(__file__).parent / "greeting.txt"
+    with open(path, "r", encoding="utf-8") as file:
         return file.read()
 
 

python-mcp-client/source-code-final/pyproject.toml

@@ -5,8 +5,8 @@ description = "MCP client for testing MCP servers."
 readme = "README.md"
 requires-python = ">=3.14"
 dependencies = [
-    "mcp>=1.20.0",
-    "openai>=2.6.1",
+    "mcp>=2.2.0,<3.0",
+    "openai>=3.16.2,<4.0",
 ]
 
 [project.scripts]