@@ -21,6 +21,8 @@
 import vertexai
 from google.cloud.aiplatform import initializer
 from vertexai.preview import reasoning_engines
+from vertexai.preview.generative_models import grounding
+from vertexai.generative_models import Tool
 import pytest
 
 
@@ -81,6 +83,12 @@ def langchain_dump_mock():
 yield langchain_dump_mock
 
 
+@pytest.fixture
+def mock_chatvertexai():
+with mock.("langchain_google_vertexai.ChatVertexAI") as model_mock:
+yield model_mock
+
+
 @pytest.mark.usefixtures("google_auth_mock")
 class TestLangchainAgent:
 def setup_method(self):
@@ -113,19 +121,23 @@ def test_initialization(self):
 assert agent._location == _TEST_LOCATION
 assert agent._runnable is None
 
-def test_initialization_with_tools(self):
+def test_initialization_with_tools(self, mock_chatvertexai):
 tools = [
 place_tool_query,
 StructuredTool.from_function(place_photo_query),
+Tool.from_google_search_retrieval(grounding.GoogleSearchRetrieval()),
 ]
 agent = reasoning_engines.LangchainAgent(
 model=_TEST_MODEL,
 tools=tools,
 )
 for tool, agent_tool in zip(tools, agent._tools):
 assert isinstance(agent_tool, type(tool))
+assert agent._runnable is None
+agent.set_up()
+assert agent._runnable is not None
 
-def test_set_up(self, vertexai_init_mock):
+def test_set_up(self):
 agent = reasoning_engines.LangchainAgent(
 model=_TEST_MODEL,
 prompt=self.prompt,
@@ -135,7 +147,7 @@ def test_set_up(self, vertexai_init_mock):
 agent.set_up()
 assert agent._runnable is not None
 
-def test_clone(self, vertexai_init_mock):
+def test_clone(self):
 agent = reasoning_engines.LangchainAgent(
 model=_TEST_MODEL,
 prompt=self.prompt,

@@ -42,6 +42,13 @@
 RunnableConfig = Any
 RunnableSerializable = Any
 
+try:
+from langchain_google_vertexai.functions_utils import _ToolsType
+
+_ToolLike = _ToolsType
+except ImportError:
+_ToolLike = Any
+
 
 def _default_runnable_kwargs(has_history: bool) -> Mapping[str, Any]:
 # https://.com/langchain-ai/langchain/blob/5784dfed001730530637793bea1795d9d5a7c244/libs/core/langchain_core/runnables/history.py#L237-L241
@@ -62,7 +69,13 @@ def _default_runnable_kwargs(has_history: bool) -> Mapping[str, Any]:
 
 
 def _default_output_parser():
-from langchain.agents.output_parsers.tools import ToolsAgentOutputParser
+try:
+from langchain.agents.output_parsers.tools import ToolsAgentOutputParser
+except (ModuleNotFoundError, ImportError):
+# Fallback to an older version if needed.
+from langchain.agents.output_parsers.openai_tools import (
+OpenAIToolsAgentOutputParser as ToolsAgentOutputParser,
+)
 
 return ToolsAgentOutputParser()
 
@@ -90,7 +103,7 @@ def _default_model_builder(
 def _default_runnable_builder(
 model: "BaseLanguageModel",
 *,
-tools: Optional[Sequence[Union[Callable, "BaseTool"]]] = None,
+tools: Optional[Sequence["_ToolLike"]] = None,
 prompt: Optional["RunnableSerializable"] = None,
 output_parser: Optional["RunnableSerializable"] = None,
 chat_history: Optional["GetSessionHistoryCallable"] = None,
@@ -123,6 +136,7 @@ def _default_runnable_builder(
 if isinstance(tool, lc_tools.BaseTool)
 else StructuredTool.from_function(tool)
 for tool in tools
+if isinstance(tool, (Callable, lc_tools.BaseTool))
 ],
 **agent_executor_kwargs,
 )
@@ -139,7 +153,14 @@ def _default_runnable_builder(
 
 def _default_prompt(has_history: bool) -> "RunnableSerializable":
 from langchain_core import prompts
-from langchain.agents.format_scratchpad.tools import format_to_tool_messages
+
+try:
+from langchain.agents.format_scratchpad.tools import format_to_tool_messages
+except (ModuleNotFoundError, ImportError):
+# Fallback to an older version if needed.
+from langchain.agents.format_scratchpad.openai_tools import (
+format_to_openai_tool_messages as format_to_tool_messages,
+)
 
 if has_history:
 return {
@@ -186,12 +207,10 @@ def _validate_callable_parameters_are_annotated(callable: Callable):
 )
 
 
-def _validate_tools(tools: Sequence[Union[Callable, "BaseTool"]]):
+def _validate_tools(tools: Sequence["_ToolLike"]):
 """Validates that the tools are usable for tool calling."""
-from langchain_core import tools as lc_tools
-
 for tool in tools:
-if not isinstance(tool, lc_tools.BaseTool):
+if isinstance(tool, Callable):
 _validate_callable_parameters_are_annotated(tool)
 
 
@@ -208,7 +227,7 @@ def __init__(
 model: str,
 *,
 prompt: Optional["RunnableSerializable"] = None,
-tools: Optional[Sequence[Union[Callable, "BaseTool"]]] = None,
+tools: Optional[Sequence["_ToolLike"]] = None,
 output_parser: Optional["RunnableSerializable"] = None,
 chat_history: Optional["GetSessionHistoryCallable"] = None,
 model_kwargs: Optional[Mapping[str, Any]] = None,