fix: add the missing from_config class method in BaseToolset

PiperOrigin-RevId: 799393801

Author: Jacksunwei

src/google/adk/tools/base_toolset.py

@@ -22,14 +22,17 @@
 from typing import Optional
 from typing import Protocol
 from typing import runtime_checkable
+from typing import Type
 from typing import TYPE_CHECKING
+from typing import TypeVar
 from typing import Union
 
 from ..agents.readonly_context import ReadonlyContext
 from .base_tool import BaseTool
 
 if TYPE_CHECKING:
   from ..models.llm_request import LlmRequest
+  from .tool_configs import ToolArgsConfig
   from .tool_context import ToolContext
 
 
@@ -53,6 +56,9 @@ def __call__(
     """
 
 
+SelfToolset = TypeVar("SelfToolset", bound="BaseToolset")
+
+
 class BaseToolset(ABC):
   """Base class for toolset.
 
@@ -152,6 +158,22 @@ async def close(self) -> None:
       resources are properly released to prevent leaks.
     """
 
+  @classmethod
+  def from_config(
+      cls: Type[SelfToolset], config: ToolArgsConfig, config_abs_path: str
+  ) -> SelfToolset:
+    """Creates a toolset instance from a config.
+
+    Args:
+      config: The config for the tool.
+      config_abs_path: The absolute path to the config file that contains the
+        tool config.
+
+    Returns:
+      The toolset instance.
+    """
+    raise ValueError(f"from_config() not implemented for toolset: {cls}")
+
   def _is_tool_selected(
       self, tool: BaseTool, readonly_context: ReadonlyContext
   ) -> bool: