linting: clean up code a bit (#246)

Author: eyurtsev

langchain_mcp_adapters/client.py

@@ -1,7 +1,8 @@
 import asyncio
+from collections.abc import AsyncIterator
 from contextlib import asynccontextmanager
 from types import TracebackType
-from typing import Any, AsyncIterator
+from typing import Any
 
 from langchain_core.documents.base import Blob
 from langchain_core.messages import AIMessage, HumanMessage
@@ -35,10 +36,7 @@
 class MultiServerMCPClient:
     """Client for connecting to multiple MCP servers and loading LangChain-compatible tools, prompts and resources from them."""
 
-    def __init__(
-        self,
-        connections: dict[str, Connection] | None = None,
-    ) -> None:
+    def __init__(self, connections: dict[str, Connection] | None = None) -> None:
         """Initialize a MultiServerMCPClient with MCP servers connections.
 
         Args:
@@ -78,15 +76,13 @@ def __init__(
         async with client.session("math") as session:
             tools = await load_mcp_tools(session)
         ```
+
         """
         self.connections: dict[str, Connection] = connections if connections is not None else {}
 
     @asynccontextmanager
     async def session(
-        self,
-        server_name: str,
-        *,
-        auto_initialize: bool = True,
+        self, server_name: str, *, auto_initialize: bool = True
     ) -> AsyncIterator[ClientSession]:
         """Connect to an MCP server and initialize a session.
 
@@ -99,6 +95,7 @@ async def session(
 
         Yields:
             An initialized ClientSession
+
         """
         if server_name not in self.connections:
             raise ValueError(
@@ -121,6 +118,7 @@ async def get_tools(self, *, server_name: str | None = None) -> list[BaseTool]:
 
         Returns:
             A list of LangChain tools
+
         """
         if server_name is not None:
             if server_name not in self.connections:
@@ -158,6 +156,7 @@ async def get_resources(
 
         Returns:
             A list of LangChain Blobs
+
         """
         async with self.session(server_name) as session:
             resources = await load_mcp_resources(session, uris=uris)
@@ -176,8 +175,8 @@ def __aexit__(
 
 
 __all__ = [
-    "MultiServerMCPClient",
     "McpHttpClientFactory",
+    "MultiServerMCPClient",
     "SSEConnection",
     "StdioConnection",
     "StreamableHttpConnection",

langchain_mcp_adapters/prompts.py

@@ -15,14 +15,14 @@ def convert_mcp_prompt_message_to_langchain_message(
 
     Returns:
         A LangChain message
+
     """
     if message.content.type == "text":
         if message.role == "user":
             return HumanMessage(content=message.content.text)
-        elif message.role == "assistant":
+        if message.role == "assistant":
             return AIMessage(content=message.content.text)
-        else:
-            raise ValueError(f"Unsupported prompt message role: {message.role}")
+        raise ValueError(f"Unsupported prompt message role: {message.role}")
 
     raise ValueError(f"Unsupported prompt message content type: {message.content.type}")
 

langchain_mcp_adapters/resources.py

@@ -5,10 +5,7 @@
 from mcp.types import BlobResourceContents, ResourceContents, TextResourceContents
 
 
-def convert_mcp_resource_to_langchain_blob(
-    resource_uri: str,
-    contents: ResourceContents,
-) -> Blob:
+def convert_mcp_resource_to_langchain_blob(resource_uri: str, contents: ResourceContents) -> Blob:
     """Convert an MCP resource content to a LangChain Blob.
 
     Args:
@@ -17,6 +14,7 @@ def convert_mcp_resource_to_langchain_blob(
 
     Returns:
         A LangChain Blob
+
     """
     if isinstance(contents, TextResourceContents):
         data = contents.text
@@ -25,11 +23,7 @@ def convert_mcp_resource_to_langchain_blob(
     else:
         raise ValueError(f"Unsupported content type for URI {resource_uri}")
 
-    return Blob.from_data(
-        data=data,
-        mime_type=contents.mimeType,
-        metadata={"uri": resource_uri},
-    )
+    return Blob.from_data(data=data, mime_type=contents.mimeType, metadata={"uri": resource_uri})
 
 
 async def get_mcp_resource(session: ClientSession, uri: str) -> list[Blob]:
@@ -41,6 +35,7 @@ async def get_mcp_resource(session: ClientSession, uri: str) -> list[Blob]:
 
     Returns:
         A list of LangChain Blobs
+
     """
     contents_result = await session.read_resource(uri)
     if not contents_result.contents or len(contents_result.contents) == 0:
@@ -52,9 +47,7 @@ async def get_mcp_resource(session: ClientSession, uri: str) -> list[Blob]:
 
 
 async def load_mcp_resources(
-    session: ClientSession,
-    *,
-    uris: str | list[str] | None = None,
+    session: ClientSession, *, uris: str | list[str] | None = None
 ) -> list[Blob]:
     """Load MCP resources and convert them to LangChain Blobs.
 
@@ -68,6 +61,7 @@ async def load_mcp_resources(
 
     Returns:
         A list of LangChain Blobs
+
     """
     blobs = []
 

langchain_mcp_adapters/sessions.py

@@ -1,10 +1,11 @@
 from __future__ import annotations
 
 import os
+from collections.abc import AsyncIterator
 from contextlib import asynccontextmanager
 from datetime import timedelta
 from pathlib import Path
-from typing import Any, AsyncIterator, Literal, Protocol
+from typing import Any, Literal, Protocol
 
 import httpx
 from mcp import ClientSession, StdioServerParameters
@@ -152,6 +153,7 @@ async def _create_stdio_session(
         encoding: Character encoding
         encoding_error_handler: How to handle encoding errors
         session_kwargs: Additional keyword arguments to pass to the ClientSession
+
     """
     # NOTE: execution commands (e.g., `uvx` / `npx`) require PATH envvar to be set.
     # To address this, we automatically inject existing PATH envvar into the `env` value,
@@ -196,6 +198,7 @@ async def _create_sse_session(
         session_kwargs: Additional keyword arguments to pass to the ClientSession
         httpx_client_factory: Custom factory for httpx.AsyncClient (optional)
         auth: httpx.Auth | None = None
+
     """
     # Create and store the connection
     kwargs = {}
@@ -233,6 +236,7 @@ async def _create_streamable_http_session(
         session_kwargs: Additional keyword arguments to pass to the ClientSession
         httpx_client_factory: Custom factory for httpx.AsyncClient (optional)
         auth: httpx.Auth | None = None
+
     """
     # Create and store the connection
     kwargs = {}
@@ -248,9 +252,7 @@ async def _create_streamable_http_session(
 
 @asynccontextmanager
 async def _create_websocket_session(
-    *,
-    url: str,
-    session_kwargs: dict[str, Any] | None = None,
+    *, url: str, session_kwargs: dict[str, Any] | None = None
 ) -> AsyncIterator[ClientSession]:
     """Create a new session to an MCP server using Websockets.
 
@@ -260,6 +262,7 @@ async def _create_websocket_session(
 
     Raises:
         ImportError: If websockets package is not installed
+
     """
     try:
         from mcp.client.websocket import websocket_client
@@ -276,9 +279,7 @@ async def _create_websocket_session(
 
 
 @asynccontextmanager
-async def create_session(
-    connection: Connection,
-) -> AsyncIterator[ClientSession]:
+async def create_session(connection: Connection) -> AsyncIterator[ClientSession]:
     """Create a new session to an MCP server.
 
     Args:
@@ -290,8 +291,8 @@ async def create_session(
 
     Yields:
         A ClientSession
-    """
 
+    """
     if "transport" not in connection:
         raise ValueError(
             "Configuration error: Missing 'transport' key in server configuration. "
@@ -350,8 +351,7 @@ async def create_session(
         if "url" not in connection:
             raise ValueError("'url' parameter is required for Websocket connection")
         async with _create_websocket_session(
-            url=connection["url"],
-            session_kwargs=connection.get("session_kwargs"),
+            url=connection["url"], session_kwargs=connection.get("session_kwargs")
         ) as session:
             yield session
     else:

langchain_mcp_adapters/tools.py

@@ -5,15 +5,8 @@
 from mcp import ClientSession
 from mcp.server.fastmcp.tools import Tool as FastMCPTool
 from mcp.server.fastmcp.utilities.func_metadata import ArgModelBase, FuncMetadata
-from mcp.types import (
-    CallToolResult,
-    EmbeddedResource,
-    ImageContent,
-    TextContent,
-)
-from mcp.types import (
-    Tool as MCPTool,
-)
+from mcp.types import CallToolResult, EmbeddedResource, ImageContent, TextContent
+from mcp.types import Tool as MCPTool
 from pydantic import BaseModel, create_model
 
 from langchain_mcp_adapters.sessions import Connection, create_session
@@ -69,10 +62,7 @@ async def _list_all_tools(session: ClientSession) -> list[MCPTool]:
 
 
 def convert_mcp_tool_to_langchain_tool(
-    session: ClientSession | None,
-    tool: MCPTool,
-    *,
-    connection: Connection | None = None,
+    session: ClientSession | None, tool: MCPTool, *, connection: Connection | None = None
 ) -> BaseTool:
     """Convert an MCP tool to a LangChain tool.
 
@@ -86,6 +76,7 @@ def convert_mcp_tool_to_langchain_tool(
 
     Returns:
         a LangChain tool
+
     """
     if session is None and connection is None:
         raise ValueError("Either a session or a connection config must be provided")
@@ -97,7 +88,7 @@ async def call_tool(
             # If a session is not provided, we will create one on the fly
             async with create_session(connection) as tool_session:
                 await tool_session.initialize()
-                call_tool_result = await cast(ClientSession, tool_session).call_tool(
+                call_tool_result = await cast("ClientSession", tool_session).call_tool(
                     tool.name, arguments
                 )
         else:
@@ -115,15 +106,14 @@ async def call_tool(
 
 
 async def load_mcp_tools(
-    session: ClientSession | None,
-    *,
-    connection: Connection | None = None,
+    session: ClientSession | None, *, connection: Connection | None = None
 ) -> list[BaseTool]:
     """Load all available MCP tools and convert them to LangChain tools.
 
     Returns:
         list of LangChain tools. Tool annotations are returned as part
         of the tool metadata object.
+
     """
     if session is None and connection is None:
         raise ValueError("Either a session or a connection config must be provided")
@@ -171,11 +161,7 @@ def to_fastmcp(tool: BaseTool) -> FastMCPTool:
         field: (field_info.annotation, field_info)
         for field, field_info in tool.tool_call_schema.model_fields.items()
     }
-    arg_model = create_model(
-        f"{tool.name}Arguments",
-        **field_definitions,
-        __base__=ArgModelBase,
-    )
+    arg_model = create_model(f"{tool.name}Arguments", **field_definitions, __base__=ArgModelBase)
     fn_metadata = FuncMetadata(arg_model=arg_model)
 
     async def fn(**arguments: dict[str, Any]) -> Any: