update mcp toolset and sample agent based on new tool_filter definition

PiperOrigin-RevId: 757969950

contributing/samples/mcp_agent/agent.py

@@ -34,8 +34,12 @@ root_agent = LlmAgent(
                 ],
             ),
             # don't want agent to do write operation
-            tool_predicate=lambda tool, ctx=None: tool.name
-            not in ('write_file', 'edit_file', 'create_directory', 'move_file'),
+            tool_filter=[
+                'write_file',
+                'edit_file',
+                'create_directory',
+                'move_file',
+            ],
         )
     ],
 )

src/google/adk/tools/base_toolset.py

@@ -1,12 +1,13 @@
 from abc import ABC
 from abc import abstractmethod
-from typing import Optional
+from typing import Optional, runtime_checkable
 from typing import Protocol
 
 from google.adk.agents.readonly_context import ReadonlyContext
 from google.adk.tools.base_tool import BaseTool
 
 
+@runtime_checkable
 class ToolPredicate(Protocol):
   """Base class for a predicate that defines the interface to decide whether a
 

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

@@ -97,6 +97,18 @@ class MCPToolset(BaseToolset):
     self.session = await self.session_manager.create_session()
     return self.session
 
+  def _is_selected(
+      self, tool: ..., readonly_context: Optional[ReadonlyContext]
+  ) -> bool:
+    """Checks if a tool should be selected based on the tool filter."""
+    if self.tool_filter is None:
+      return True
+    if isinstance(self.tool_filter, ToolPredicate):
+      return self.tool_filter(tool, readonly_context)
+    if isinstance(self.tool_filter, list):
+      return tool.name in self.tool_filter
+    return False
+
   @override
   async def close(self):
     """Closes the connection to MCP Server."""
@@ -123,5 +135,5 @@ class MCPToolset(BaseToolset):
             mcp_session_manager=self.session_manager,
         )
         for tool in tools_response.tools
-        if self.tool_filter is None or self.tool_filter(tool, readonly_context)
+        if self._is_selected(tool, readonly_context)
     ]