Added support for native tool calls to vertex ai. (brainlid#359)

Author: raulchedrese

lib/chat_models/chat_vertex_ai.ex

@@ -53,6 +53,8 @@ defmodule LangChain.ChatModels.ChatVertexAI do
   alias LangChain.Utils
   alias LangChain.Callbacks
   alias LangChain.TokenUsage
+  alias LangChain.NativeTool
+  alias LangChain.Function
 
   @behaviour ChatModel
 
@@ -305,6 +307,14 @@ defmodule LangChain.ChatModels.ChatVertexAI do
     }
   end
 
+  defp for_api(%NativeTool{name: name, configuration: %{} = config}) do
+    %{name => config}
+  end
+
+  defp for_api(%NativeTool{name: name, configuration: nil}) do
+    name
+  end
+
   defp for_api(nil), do: nil
 
   @doc """

test/chat_models/chat_vertex_ai_test.exs

@@ -601,4 +601,32 @@ defmodule ChatModels.ChatVertexAITest do
       assert %TokenUsage{input: 7, output: 2} = usage
     end
   end
+
+  describe "google_search native tool" do
+    @tag live_call: true, live_google_ai: true
+    test "should include grounding metadata in response" do
+      alias LangChain.Chains.LLMChain
+      alias LangChain.Message
+      alias LangChain.NativeTool
+
+      chat =
+        ChatVertexAI.new!(%{
+          model: "gemini-2.5-flash",
+          temperature: 0,
+          endpoint: System.fetch_env!("VERTEX_API_ENDPOINT"),
+          stream: true
+        })
+
+      {:ok, updated_chain} =
+        %{llm: chat, verbose: false, stream: false}
+        |> LLMChain.new!()
+        |> LLMChain.add_message(Message.new_user!("What is the current Google stock price?"))
+        |> LLMChain.add_tools(NativeTool.new!(%{name: "google_search", configuration: %{}}))
+        |> LLMChain.run()
+
+      assert %Message{} = updated_chain.last_message
+      assert updated_chain.last_message.role == :assistant
+      assert Map.has_key?(updated_chain.last_message.metadata, "groundingChunks")
+    end
+  end
 end