Add type checker to examples/client (#1837)

Author: Kludex

examples/clients/conformance-auth-client/mcp_conformance_auth_client/__init__.py

@@ -29,7 +29,8 @@
 import logging
 import os
 import sys
-from urllib.parse import ParseResult, parse_qs, urlparse
+from typing import Any, cast
+from urllib.parse import parse_qs, urlparse
 
 import httpx
 from mcp import ClientSession
@@ -39,12 +40,12 @@
     PrivateKeyJWTOAuthProvider,
     SignedJWTParameters,
 )
-from mcp.client.streamable_http import streamablehttp_client
+from mcp.client.streamable_http import streamable_http_client
 from mcp.shared.auth import OAuthClientInformationFull, OAuthClientMetadata, OAuthToken
 from pydantic import AnyUrl
 
 
-def get_conformance_context() -> dict:
+def get_conformance_context() -> dict[str, Any]:
     """Load conformance test context from MCP_CONFORMANCE_CONTEXT environment variable."""
     context_json = os.environ.get("MCP_CONFORMANCE_CONTEXT")
     if not context_json:
@@ -116,9 +117,9 @@ async def handle_redirect(self, authorization_url: str) -> None:
 
             # Check for redirect response
             if response.status_code in (301, 302, 303, 307, 308):
-                location = response.headers.get("location")
+                location = cast(str, response.headers.get("location"))
                 if location:
-                    redirect_url: ParseResult = urlparse(location)
+                    redirect_url = urlparse(location)
                     query_params: dict[str, list[str]] = parse_qs(redirect_url.query)
 
                     if "code" in query_params:
@@ -259,12 +260,8 @@ async def run_client_credentials_basic_client(server_url: str) -> None:
 async def _run_session(server_url: str, oauth_auth: OAuthClientProvider) -> None:
     """Common session logic for all OAuth flows."""
     # Connect using streamable HTTP transport with OAuth
-    async with streamablehttp_client(
-        url=server_url,
-        auth=oauth_auth,
-        timeout=30.0,
-        sse_read_timeout=60.0,
-    ) as (read_stream, write_stream, _):
+    client = httpx.AsyncClient(auth=oauth_auth, timeout=30.0)
+    async with streamable_http_client(url=server_url, http_client=client) as (read_stream, write_stream, _):
         async with ClientSession(read_stream, write_stream) as session:
             # Initialize the session
             await session.initialize()

examples/clients/simple-auth-client/mcp_simple_auth_client/main.py

@@ -6,21 +6,26 @@
 
 """
 
+from __future__ import annotations as _annotations
+
 import asyncio
 import os
+import socketserver
 import threading
 import time
 import webbrowser
 from http.server import BaseHTTPRequestHandler, HTTPServer
-from typing import Any
+from typing import Any, Callable
 from urllib.parse import parse_qs, urlparse
 
 import httpx
+from anyio.streams.memory import MemoryObjectReceiveStream, MemoryObjectSendStream
 from mcp.client.auth import OAuthClientProvider, TokenStorage
 from mcp.client.session import ClientSession
 from mcp.client.sse import sse_client
 from mcp.client.streamable_http import streamable_http_client
 from mcp.shared.auth import OAuthClientInformationFull, OAuthClientMetadata, OAuthToken
+from mcp.shared.message import SessionMessage
 
 
 class InMemoryTokenStorage(TokenStorage):
@@ -46,7 +51,13 @@ async def set_client_info(self, client_info: OAuthClientInformationFull) -> None
 class CallbackHandler(BaseHTTPRequestHandler):
     """Simple HTTP handler to capture OAuth callback."""
 
-    def __init__(self, request, client_address, server, callback_data):
+    def __init__(
+        self,
+        request: Any,
+        client_address: tuple[str, int],
+        server: socketserver.BaseServer,
+        callback_data: dict[str, Any],
+    ):
         """Initialize with callback data storage."""
         self.callback_data = callback_data
         super().__init__(request, client_address, server)
@@ -91,15 +102,14 @@ def do_GET(self):
             self.send_response(404)
             self.end_headers()
 
-    def log_message(self, format, *args):
+    def log_message(self, format: str, *args: Any):
         """Suppress default logging."""
-        pass
 
 
 class CallbackServer:
     """Simple server to handle OAuth callbacks."""
 
-    def __init__(self, port=3000):
+    def __init__(self, port: int = 3000):
         self.port = port
         self.server = None
         self.thread = None
@@ -110,7 +120,12 @@ def _create_handler_with_data(self):
         callback_data = self.callback_data
 
         class DataCallbackHandler(CallbackHandler):
-            def __init__(self, request, client_address, server):
+            def __init__(
+                self,
+                request: BaseHTTPRequestHandler,
+                client_address: tuple[str, int],
+                server: socketserver.BaseServer,
+            ):
                 super().__init__(request, client_address, server, callback_data)
 
         return DataCallbackHandler
@@ -131,7 +146,7 @@ def stop(self):
         if self.thread:
             self.thread.join(timeout=1)
 
-    def wait_for_callback(self, timeout=300):
+    def wait_for_callback(self, timeout: int = 300):
         """Wait for OAuth callback with timeout."""
         start_time = time.time()
         while time.time() - start_time < timeout:
@@ -225,7 +240,12 @@ async def _default_redirect_handler(authorization_url: str) -> None:
 
             traceback.print_exc()
 
-    async def _run_session(self, read_stream, write_stream, get_session_id):
+    async def _run_session(
+        self,
+        read_stream: MemoryObjectReceiveStream[SessionMessage | Exception],
+        write_stream: MemoryObjectSendStream[SessionMessage],
+        get_session_id: Callable[[], str | None] | None = None,
+    ):
         """Run the MCP session with the given streams."""
         print("🤝 Initializing MCP session...")
         async with ClientSession(read_stream, write_stream) as session:
@@ -314,7 +334,7 @@ async def interactive_loop(self):
                         continue
 
                     # Parse arguments (simple JSON-like format)
-                    arguments = {}
+                    arguments: dict[str, Any] = {}
                     if len(parts) > 2:
                         import json
 

examples/clients/simple-chatbot/mcp_simple_chatbot/main.py

@@ -1,3 +1,5 @@
+from __future__ import annotations
+
 import asyncio
 import json
 import logging
@@ -93,7 +95,7 @@ async def initialize(self) -> None:
             await self.cleanup()
             raise
 
-    async def list_tools(self) -> list[Any]:
+    async def list_tools(self) -> list[Tool]:
         """List available tools from the server.
 
         Returns:
@@ -106,10 +108,10 @@ async def list_tools(self) -> list[Any]:
             raise RuntimeError(f"Server {self.name} not initialized")
 
         tools_response = await self.session.list_tools()
-        tools = []
+        tools: list[Tool] = []
 
         for item in tools_response:
-            if isinstance(item, tuple) and item[0] == "tools":
+            if item[0] == "tools":
                 tools.extend(Tool(tool.name, tool.description, tool.inputSchema, tool.title) for tool in item[1])
 
         return tools
@@ -189,7 +191,7 @@ def format_for_llm(self) -> str:
         Returns:
             A formatted string describing the tool.
         """
-        args_desc = []
+        args_desc: list[str] = []
         if "properties" in self.input_schema:
             for param_name, param_info in self.input_schema["properties"].items():
                 arg_desc = f"- {param_name}: {param_info.get('description', 'No description')}"
@@ -311,9 +313,9 @@ def _clean_json_string(json_string: str) -> str:
                             result = await server.execute_tool(tool_call["tool"], tool_call["arguments"])
 
                             if isinstance(result, dict) and "progress" in result:
-                                progress = result["progress"]
-                                total = result["total"]
-                                percentage = (progress / total) * 100
+                                progress = result["progress"]  # type: ignore
+                                total = result["total"]  # type: ignore
+                                percentage = (progress / total) * 100  # type: ignore
                                 logging.info(f"Progress: {progress}/{total} ({percentage:.1f}%)")
 
                             return f"Tool execution result: {result}"
@@ -338,7 +340,7 @@ async def start(self) -> None:
                     await self.cleanup_servers()
                     return
 
-            all_tools = []
+            all_tools: list[Tool] = []
             for server in self.servers:
                 tools = await server.list_tools()
                 all_tools.extend(tools)

examples/clients/simple-task-client/mcp_simple_task_client/main.py

@@ -4,12 +4,12 @@
 
 import click
 from mcp import ClientSession
-from mcp.client.streamable_http import streamablehttp_client
+from mcp.client.streamable_http import streamable_http_client
 from mcp.types import CallToolResult, TextContent
 
 
 async def run(url: str) -> None:
-    async with streamablehttp_client(url) as (read, write, _):
+    async with streamable_http_client(url) as (read, write, _):
         async with ClientSession(read, write) as session:
             await session.initialize()
 
@@ -28,12 +28,13 @@ async def run(url: str) -> None:
             task_id = result.task.taskId
             print(f"Task created: {task_id}")
 
+            status = None
             # Poll until done (respects server's pollInterval hint)
             async for status in session.experimental.poll_task(task_id):
                 print(f"  Status: {status.status} - {status.statusMessage or ''}")
 
             # Check final status
-            if status.status != "completed":
+            if status and status.status != "completed":
                 print(f"Task ended with status: {status.status}")
                 return
 

examples/clients/simple-task-interactive-client/mcp_simple_task_interactive_client/main.py

@@ -11,7 +11,7 @@
 
 import click
 from mcp import ClientSession
-from mcp.client.streamable_http import streamablehttp_client
+from mcp.client.streamable_http import streamable_http_client
 from mcp.shared.context import RequestContext
 from mcp.types import (
     CallToolResult,
@@ -73,7 +73,7 @@ def get_text(result: CallToolResult) -> str:
 
 
 async def run(url: str) -> None:
-    async with streamablehttp_client(url) as (read, write, _):
+    async with streamable_http_client(url) as (read, write, _):
         async with ClientSession(
             read,
             write,

examples/clients/sse-polling-client/mcp_sse_polling_client/main.py

@@ -20,7 +20,7 @@
 
 import click
 from mcp import ClientSession
-from mcp.client.streamable_http import streamablehttp_client
+from mcp.client.streamable_http import streamable_http_client
 
 logger = logging.getLogger(__name__)
 
@@ -34,7 +34,7 @@ async def run_demo(url: str, items: int, checkpoint_every: int) -> None:
     print(f"Processing {items} items with checkpoints every {checkpoint_every}")
     print(f"{'=' * 60}\n")
 
-    async with streamablehttp_client(url) as (read_stream, write_stream, _):
+    async with streamable_http_client(url) as (read_stream, write_stream, _):
         async with ClientSession(read_stream, write_stream) as session:
             # Initialize the connection
             print("Initializing connection...")

pyproject.toml

@@ -93,7 +93,13 @@ packages = ["src/mcp"]
 
 [tool.pyright]
 typeCheckingMode = "strict"
-include = ["src/mcp", "tests", "examples/servers", "examples/snippets"]
+include = [
+    "src/mcp",
+    "tests",
+    "examples/servers",
+    "examples/snippets",
+    "examples/clients",
+]
 venvPath = "."
 venv = ".venv"
 # The FastAPI style of using decorators in tests gives a `reportUnusedFunction` error.
@@ -102,7 +108,9 @@ venv = ".venv"
 # those private functions instead of testing the private functions directly. It makes it easier to maintain the code source
 # and refactor code that is not public.
 executionEnvironments = [
-    { root = "tests", extraPaths = ["."], reportUnusedFunction = false, reportPrivateUsage = false },
+    { root = "tests", extraPaths = [
+        ".",
+    ], reportUnusedFunction = false, reportPrivateUsage = false },
     { root = "examples/servers", reportUnusedFunction = false },
 ]