chore: add D212 lint rule to enforce Google-style docstrings (#1892)

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

@@ -1,6 +1,5 @@
 #!/usr/bin/env python3
-"""
-MCP OAuth conformance test client.
+"""MCP OAuth conformance test client.
 
 This client is designed to work with the MCP conformance test framework.
 It automatically handles OAuth flows without user interaction by programmatically
@@ -89,8 +88,7 @@ class InMemoryTokenStorage(TokenStorage):
 
 
 class ConformanceOAuthCallbackHandler:
-    """
-    OAuth callback handler that automatically fetches the authorization URL
+    """OAuth callback handler that automatically fetches the authorization URL
     and extracts the auth code, without requiring user interaction.
 
     This mimics the behavior of the TypeScript ConformanceOAuthProvider.
@@ -101,8 +99,7 @@ class ConformanceOAuthCallbackHandler:
         self._state: str | None = None
 
     async def handle_redirect(self, authorization_url: str) -> None:
-        """
-        Fetch the authorization URL and extract the auth code from the redirect.
+        """Fetch the authorization URL and extract the auth code from the redirect.
 
         The conformance test server returns a redirect with the auth code,
         so we can capture it programmatically.
@@ -148,8 +145,7 @@ class ConformanceOAuthCallbackHandler:
 
 
 async def run_authorization_code_client(server_url: str) -> None:
-    """
-    Run the conformance test client with authorization code flow.
+    """Run the conformance test client with authorization code flow.
 
     This function:
     1. Connects to the MCP server with OAuth authorization code flow
@@ -180,8 +176,7 @@ async def run_authorization_code_client(server_url: str) -> None:
 
 
 async def run_client_credentials_jwt_client(server_url: str) -> None:
-    """
-    Run the conformance test client with client credentials flow using private_key_jwt (SEP-1046).
+    """Run the conformance test client with client credentials flow using private_key_jwt (SEP-1046).
 
     This function:
     1. Connects to the MCP server with OAuth client_credentials grant
@@ -223,8 +218,7 @@ async def run_client_credentials_jwt_client(server_url: str) -> None:
 
 
 async def run_client_credentials_basic_client(server_url: str) -> None:
-    """
-    Run the conformance test client with client credentials flow using client_secret_basic.
+    """Run the conformance test client with client credentials flow using client_secret_basic.
 
     This function:
     1. Connects to the MCP server with OAuth client_credentials grant

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

@@ -1,6 +1,5 @@
 #!/usr/bin/env python3
-"""
-Simple MCP client example with OAuth authentication support.
+"""Simple MCP client example with OAuth authentication support.
 
 This client connects to an MCP server using streamable HTTP transport with OAuth.
 

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

@@ -1,5 +1,4 @@
-"""
-SSE Polling Demo Client
+"""SSE Polling Demo Client
 
 Demonstrates the client-side auto-reconnect for SSE polling pattern.
 

examples/fastmcp/complex_inputs.py

@@ -1,5 +1,4 @@
-"""
-FastMCP Complex inputs Example
+"""FastMCP Complex inputs Example
 
 Demonstrates validation via pydantic with complex models.
 """

examples/fastmcp/desktop.py

@@ -1,5 +1,4 @@
-"""
-FastMCP Desktop Example
+"""FastMCP Desktop Example
 
 A simple example that exposes the desktop directory as a resource.
 """

examples/fastmcp/direct_call_tool_result_return.py

@@ -1,6 +1,4 @@
-"""
-FastMCP Echo Server with direct CallToolResult return
-"""
+"""FastMCP Echo Server with direct CallToolResult return"""
 
 from typing import Annotated
 

examples/fastmcp/echo.py

@@ -1,6 +1,4 @@
-"""
-FastMCP Echo Server
-"""
+"""FastMCP Echo Server"""
 
 from mcp.server.fastmcp import FastMCP
 

examples/fastmcp/icons_demo.py

@@ -1,5 +1,4 @@
-"""
-FastMCP Icons Demo Server
+"""FastMCP Icons Demo Server
 
 Demonstrates using icons with tools, resources, prompts, and implementation.
 """

examples/fastmcp/logging_and_progress.py

@@ -1,6 +1,4 @@
-"""
-FastMCP Echo Server that sends log messages and progress updates to the client
-"""
+"""FastMCP Echo Server that sends log messages and progress updates to the client"""
 
 import asyncio
 

examples/fastmcp/memory.py

@@ -4,8 +4,7 @@
 
 # uv pip install 'pydantic-ai-slim[openai]' asyncpg numpy pgvector
 
-"""
-Recursive memory system inspired by the human brain's clustering of memories.
+"""Recursive memory system inspired by the human brain's clustering of memories.
 Uses OpenAI's 'text-embedding-3-small' model and pgvector for efficient
 similarity search.
 """

examples/fastmcp/parameter_descriptions.py

@@ -1,6 +1,4 @@
-"""
-FastMCP Example showing parameter descriptions
-"""
+"""FastMCP Example showing parameter descriptions"""
 
 from pydantic import Field
 

examples/fastmcp/screenshot.py

@@ -1,5 +1,4 @@
-"""
-FastMCP Screenshot Example
+"""FastMCP Screenshot Example
 
 Give Claude a tool to capture and view screenshots.
 """
@@ -15,8 +14,7 @@ mcp = FastMCP("Screenshot Demo")
 
 @mcp.tool()
 def take_screenshot() -> Image:
-    """
-    Take a screenshot of the user's screen and return it as an image. Use
+    """Take a screenshot of the user's screen and return it as an image. Use
     this tool anytime the user wants you to look at something they're doing.
     """
     import pyautogui

examples/fastmcp/simple_echo.py

@@ -1,6 +1,4 @@
-"""
-FastMCP Echo Server
-"""
+"""FastMCP Echo Server"""
 
 from mcp.server.fastmcp import FastMCP
 

examples/fastmcp/text_me.py

@@ -2,8 +2,7 @@
 # dependencies = []
 # ///
 
-"""
-FastMCP Text Me Server
+"""FastMCP Text Me Server
 --------------------------------
 This defines a simple FastMCP server that sends a text message to a phone number via https://surgemsg.com/.
 

examples/fastmcp/unicode_example.py

@@ -1,5 +1,4 @@
-"""
-Example FastMCP server that uses Unicode characters in various places to help test
+"""Example FastMCP server that uses Unicode characters in various places to help test
 Unicode handling in tools and inspectors.
 """
 
@@ -10,8 +9,7 @@ mcp = FastMCP()
 
 @mcp.tool(description="🌟 A tool that uses various Unicode characters in its description: á é í ó ú ñ 漢字 🎉")
 def hello_unicode(name: str = "世界", greeting: str = "¡Hola") -> str:
-    """
-    A simple tool that demonstrates Unicode handling in:
+    """A simple tool that demonstrates Unicode handling in:
     - Tool description (emojis, accents, CJK characters)
     - Parameter defaults (CJK characters)
     - Return values (Spanish punctuation, emojis)

examples/fastmcp/weather_structured.py

@@ -1,5 +1,4 @@
-"""
-FastMCP Weather Example with Structured Output
+"""FastMCP Weather Example with Structured Output
 
 Demonstrates how to use structured output with tools to return
 well-typed, validated data that clients can easily process.

examples/servers/everything-server/mcp_everything_server/server.py

@@ -1,6 +1,5 @@
 #!/usr/bin/env python3
-"""
-MCP Everything Server - Conformance Test Server
+"""MCP Everything Server - Conformance Test Server
 
 Server implementing all MCP features for conformance testing based on Conformance Server Specification.
 """

examples/servers/simple-auth/mcp_simple_auth/auth_server.py

@@ -1,5 +1,4 @@
-"""
-Authorization Server for MCP Split Demo.
+"""Authorization Server for MCP Split Demo.
 
 This server handles OAuth flows, client registration, and token issuance.
 Can be replaced with enterprise authorization servers like Auth0, Entra ID, etc.
@@ -41,8 +40,7 @@ class AuthServerSettings(BaseModel):
 
 
 class SimpleAuthProvider(SimpleOAuthProvider):
-    """
-    Authorization Server provider with simple demo authentication.
+    """Authorization Server provider with simple demo authentication.
 
     This provider:
     1. Issues MCP tokens after simple credential authentication
@@ -98,8 +96,7 @@ def create_authorization_server(server_settings: AuthServerSettings, auth_settin
 
     # Add token introspection endpoint (RFC 7662) for Resource Servers
     async def introspect_handler(request: Request) -> Response:
-        """
-        Token introspection endpoint for Resource Servers.
+        """Token introspection endpoint for Resource Servers.
 
         Resource Servers call this endpoint to validate tokens without
         needing direct access to token storage.
@@ -157,8 +154,7 @@ async def run_server(server_settings: AuthServerSettings, auth_settings: SimpleA
 @click.command()
 @click.option("--port", default=9000, help="Port to listen on")
 def main(port: int) -> int:
-    """
-    Run the MCP Authorization Server.
+    """Run the MCP Authorization Server.
 
     This server handles OAuth flows and can be used by multiple Resource Servers.
 

examples/servers/simple-auth/mcp_simple_auth/legacy_as_server.py

@@ -1,5 +1,4 @@
-"""
-Legacy Combined Authorization Server + Resource Server for MCP.
+"""Legacy Combined Authorization Server + Resource Server for MCP.
 
 This server implements the old spec where MCP servers could act as both AS and RS.
 Used for backwards compatibility testing with the new split AS/RS architecture.
@@ -87,8 +86,7 @@ def create_simple_mcp_server(server_settings: ServerSettings, auth_settings: Sim
 
     @app.tool()
     async def get_time() -> dict[str, Any]:
-        """
-        Get the current server time.
+        """Get the current server time.
 
         This tool demonstrates that system information can be protected
         by OAuth authentication. User must be authenticated to access it.

examples/servers/simple-auth/mcp_simple_auth/server.py

@@ -1,5 +1,4 @@
-"""
-MCP Resource Server with Token Introspection.
+"""MCP Resource Server with Token Introspection.
 
 This server validates tokens via Authorization Server introspection and serves MCP resources.
 Demonstrates RFC 9728 Protected Resource Metadata for AS/RS separation.
@@ -47,8 +46,7 @@ class ResourceServerSettings(BaseSettings):
 
 
 def create_resource_server(settings: ResourceServerSettings) -> FastMCP:
-    """
-    Create MCP Resource Server with token introspection.
+    """Create MCP Resource Server with token introspection.
 
     This server:
     1. Provides protected resource metadata (RFC 9728)
@@ -80,8 +78,7 @@ def create_resource_server(settings: ResourceServerSettings) -> FastMCP:
 
     @app.tool()
     async def get_time() -> dict[str, Any]:
-        """
-        Get the current server time.
+        """Get the current server time.
 
         This tool demonstrates that system information can be protected
         by OAuth authentication. User must be authenticated to access it.
@@ -114,8 +111,7 @@ def create_resource_server(settings: ResourceServerSettings) -> FastMCP:
     help="Enable RFC 8707 resource validation",
 )
 def main(port: int, auth_server: str, transport: Literal["sse", "streamable-http"], oauth_strict: bool) -> int:
-    """
-    Run the MCP Resource Server.
+    """Run the MCP Resource Server.
 
     This server:
     - Provides RFC 9728 Protected Resource Metadata