feat: Support adding a name prefix to MCPTool and MCPToolset

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

@@ -67,6 +67,7 @@ def __init__(
       mcp_session_manager: MCPSessionManager,
       auth_scheme: Optional[AuthScheme] = None,
       auth_credential: Optional[AuthCredential] = None,
+      tool_name_prefix: str = "",
   ):
     """Initializes an MCPTool.
 
@@ -78,12 +79,20 @@ def __init__(
         mcp_session_manager: The MCP session manager to use for communication.
         auth_scheme: The authentication scheme to use.
         auth_credential: The authentication credential to use.
+        tool_name_prefix: string to add to the start of the tool name. For example,
+          `prefix="ns_"` would name `my_tool` as `ns_my_tool`.
 
     Raises:
         ValueError: If mcp_tool or mcp_session_manager is None.
     """
+    if mcp_tool is None:
+      raise ValueError("mcp_tool cannot be None")
+    if mcp_session_manager is None:
+      raise ValueError("mcp_session_manager cannot be None")
+    raw_name = mcp_tool.name
+    name = tool_name_prefix + raw_name
     super().__init__(
-        name=mcp_tool.name,
+        name=name,
         description=mcp_tool.description if mcp_tool.description else "",
         auth_config=AuthConfig(
             auth_scheme=auth_scheme, raw_auth_credential=auth_credential
@@ -93,6 +102,8 @@ def __init__(
     )
     self._mcp_tool = mcp_tool
     self._mcp_session_manager = mcp_session_manager
+    self._tool_name_prefix = tool_name_prefix
+    self._raw_name = raw_name
 
   @override
   def _get_declaration(self) -> FunctionDeclaration:
@@ -128,7 +139,7 @@ async def _run_async_impl(
     # Get the session from the session manager
     session = await self._mcp_session_manager.create_session(headers=headers)
 
-    response = await session.call_tool(self.name, arguments=args)
+    response = await session.call_tool(self._mcp_tool.name, arguments=args)
     return response
 
   async def _get_headers(

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

@@ -36,8 +36,8 @@
 # Attempt to import MCP Tool from the MCP library, and hints user to upgrade
 # their Python version to 3.10 if it fails.
 try:
-  from mcp import StdioServerParameters
   from mcp.types import ListToolsResult
+  from mcp import StdioServerParameters
 except ImportError as e:
   import sys
 
@@ -68,7 +68,8 @@ class MCPToolset(BaseToolset):
           command='npx',
           args=["-y", "@modelcontextprotocol/server-filesystem"],
       ),
-      tool_filter=['read_file', 'list_directory']  # Optional: filter specific tools
+      tool_filter=['read_file', 'list_directory'],  # Optional: filter specific tools
+      tool_name_prefix="sfs_",  # Optional: add_name_prefix
   )
 
   # Use in an agent
@@ -98,6 +99,7 @@ def __init__(
       errlog: TextIO = sys.stderr,
       auth_scheme: Optional[AuthScheme] = None,
       auth_credential: Optional[AuthCredential] = None,
+      tool_name_prefix: str = "",
   ):
     """Initializes the MCPToolset.
 
@@ -110,12 +112,17 @@ def __init__(
         mcp server (e.g. using `npx` or `python3` ), but it does not support
         timeout, and we recommend to use `StdioConnectionParams` instead when
         timeout is needed.
-      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
+        In both cases, the tool name WILL include the `tool_name_prefix` when
+        matching.
       errlog: TextIO stream for error logging.
       auth_scheme: The auth scheme of the tool for tool calling
       auth_credential: The auth credential of the tool for tool calling
+      tool_name_prefix: string to add to the start of the name of all return tools.
+        For example, `prefix="ns_"` would change a returned tool name from
+        `my_tool` to `ns_my_tool`.
     """
     super().__init__(tool_filter=tool_filter)
 
@@ -124,6 +131,7 @@ def __init__(
 
     self._connection_params = connection_params
     self._errlog = errlog
+    self._tool_name_prefix = tool_name_prefix
 
     # Create the session manager that will handle the MCP connection
     self._mcp_session_manager = MCPSessionManager(
@@ -161,6 +169,7 @@ async def get_tools(
           mcp_session_manager=self._mcp_session_manager,
           auth_scheme=self._auth_scheme,
           auth_credential=self._auth_credential,
+          tool_name_prefix=self._tool_name_prefix,
       )
 
       if self._is_tool_selected(mcp_tool, readonly_context):

tests/unittests/tools/mcp_tool/test_mcp_tool.py

@@ -13,19 +13,21 @@
 # limitations under the License.
 
 import sys
-from typing import Any
-from typing import Dict
+from google.genai.types import Part
 from unittest.mock import AsyncMock
 from unittest.mock import Mock
-from unittest.mock import patch
 
+from google.adk import Agent
+from google.adk.tools import FunctionTool
 from google.adk.auth.auth_credential import AuthCredential
 from google.adk.auth.auth_credential import AuthCredentialTypes
 from google.adk.auth.auth_credential import HttpAuth
 from google.adk.auth.auth_credential import HttpCredentials
 from google.adk.auth.auth_credential import OAuth2Auth
 from google.adk.auth.auth_credential import ServiceAccount
 import pytest
+from tests.unittests import testing_utils
+
 
 # Skip all tests in this module if Python version is less than 3.10
 pytestmark = pytest.mark.skipif(
@@ -38,6 +40,7 @@
   from google.adk.tools.mcp_tool.mcp_tool import MCPTool
   from google.adk.tools.tool_context import ToolContext
   from google.genai.types import FunctionDeclaration
+  from mcp.types import Tool as McpBaseTool
 except ImportError as e:
   if sys.version_info < (3, 10):
     # Create dummy classes to prevent NameError during test collection
@@ -49,6 +52,7 @@ class DummyClass:
     MCPTool = DummyClass
     ToolContext = DummyClass
     FunctionDeclaration = DummyClass
+    McpBaseTool = DummyClass
   else:
     raise e
 
@@ -358,3 +362,79 @@ def test_init_validation(self):
 
     with pytest.raises(TypeError):
       MCPTool(mcp_tool=self.mock_mcp_tool)  # Missing session manager
+
+
+class TestMCPSession(object):
+
+  def __init__(self, function_tool: FunctionTool):
+    self._function_tool = function_tool
+
+  async def call_tool(self, name, arguments):
+    return self._function_tool.func(**arguments)
+
+
+class TestMCPSessionManager(object):
+
+  def __init__(self, function_tool: FunctionTool):
+    self._function_tool = function_tool
+
+  async def create_session(self, headers=None):
+    return TestMCPSession(self._function_tool)
+
+  async def close(self):
+    pass
+
+
+def mcp_tool(function_tool: FunctionTool, prefix=""):
+  return MCPTool(
+      mcp_tool=McpBaseTool(
+          name=function_tool.name,
+          description=function_tool.description,
+          inputSchema=function_tool._get_declaration().parameters.json_schema.model_dump(
+              exclude_none=True
+          ),
+      ),
+      mcp_session_manager=TestMCPSessionManager(function_tool),
+      tool_name_prefix=prefix,
+  )
+
+
+def test_mcp_tool():
+  @FunctionTool
+  def add(a: int, b: int):
+    """Add a and b and  retuirn the result"""
+    return a + b
+
+  mcp_add = mcp_tool(add, "mcp_")
+
+  add_call = Part.from_function_call(name="add", args={"a": 1, "b": 2})
+  add_response = Part.from_function_response(name="add", response={"result": 3})
+
+  mcp_add_call = Part.from_function_call(name="mcp_add", args={"a": 5, "b": 10})
+  mcp_add_response = Part.from_function_response(
+      name="mcp_add", response={"result": 15}
+  )
+
+  mock_model = testing_utils.MockModel.create(
+      responses=[
+          add_call,
+          mcp_add_call,
+          "response1",
+      ]
+  )
+
+  root_agent = Agent(
+      name="root_agent",
+      model=mock_model,
+      tools=[add, mcp_add],
+  )
+
+  runner = testing_utils.InMemoryRunner(root_agent)
+
+  assert testing_utils.simplify_events(runner.run("test1")) == [
+      ("root_agent", add_call),
+      ("root_agent", add_response),
+      ("root_agent", mcp_add_call),
+      ("root_agent", mcp_add_response),
+      ("root_agent", "response1"),
+  ]