chore: add more comments to MCPTooset and MCPSessionManager

PiperOrigin-RevId: 765448413

src/google/adk/tools/mcp_tool/mcp_session_manager.py

@@ -150,7 +150,8 @@ class MCPSessionManager:
 
     Args:
         connection_params: Parameters for the MCP connection (Stdio, SSE or
-          Streamable HTTP).
+          Streamable HTTP). Stdio by default also has a 5s read timeout as other
+          parameters but it's not configurable for now.
         errlog: (Optional) TextIO stream for error logging. Use only for
           initializing a local stdio MCP session.
     """
@@ -174,6 +175,9 @@ class MCPSessionManager:
 
     try:
       if isinstance(self._connection_params, StdioServerParameters):
+        # So far timeout is not configurable. Given MCP is still evolving, we
+        # would expect stdio_client to evolve to accept timeout parameter like
+        # other client.
         client = stdio_client(
             server=self._connection_params, errlog=self._errlog
         )
@@ -211,6 +215,13 @@ class MCPSessionManager:
       if isinstance(self._connection_params, StdioServerParameters):
         # Default timeout for MCP session is 5 seconds, same as SseServerParams
         # and StreamableHTTPServerParams.
+        # TODO :
+        #   1. make timeout configurable
+        #   2. Add StdioConnectionParams to include StdioServerParameters as a
+        #      field and rename other two params to XXXXConnetionParams. Ohter
+        #      two params are actually connection params, while stdio is
+        #      special, stdio_client takes the resposibility of starting the
+        #      server and working as a client.
         session = await self._exit_stack.enter_async_context(
             ClientSession(
                 *transports[:2],

src/google/adk/tools/mcp_tool/mcp_toolset.py

@@ -98,9 +98,9 @@ class MCPToolset(BaseToolset):
         `StdioServerParameters` for using local mcp server (e.g. using `npx` or
         `python3`); or `SseServerParams` for a local/remote SSE server; or
         `StreamableHTTPServerParams` for local/remote Streamable http server.
-      tool_filter: Optional filter to select specific tools. Can be either: - A
-        list of tool names to include - A ToolPredicate function for custom
-        filtering logic
+      tool_filter: Optional filter to select specific tools. Can be either:
+        - A list of tool names to include
+        - A ToolPredicate function for custom filtering logic
       errlog: TextIO stream for error logging.
     """
     super().__init__(tool_filter=tool_filter)