Fix: Allow -latest model aliases in GoogleSearchTool

Author: hemasekhar-p

core/src/main/java/com/google/adk/tools/GoogleSearchTool.java

@@ -61,8 +61,8 @@ public Completable processLlmRequest(
     ImmutableList.Builder<Tool> updatedToolsBuilder = ImmutableList.builder();
     updatedToolsBuilder.addAll(existingTools);
 
-    String model = llmRequestBuilder.build().model().get();
-    if (model != null && (model.startsWith("gemini-2") || model.startsWith("gemini-3"))) {
+    String model = llmRequestBuilder.build().model().orElse(null);
+    if (isSupportedModel(model)) {
 
       updatedToolsBuilder.add(Tool.builder().googleSearch(GoogleSearch.builder().build()).build());
       configBuilder.tools(updatedToolsBuilder.build());
@@ -74,4 +74,13 @@ public Completable processLlmRequest(
     llmRequestBuilder.config(configBuilder.build());
     return Completable.complete();
   }
+
+  private boolean isSupportedModel(String model) {
+    if (model == null) {
+      return false;
+    }
+    return model.startsWith("gemini-2")
+        || model.startsWith("gemini-3")
+        || model.endsWith("-latest");
+  }
 }

core/src/test/java/com/google/adk/tools/BaseToolTest.java

@@ -164,6 +164,33 @@ public void processLlmRequestWithGoogleSearchToolAddsToolToConfig() {
             Tool.builder().googleSearch(GoogleSearch.builder().build()).build());
   }
 
+  @Test
+  public void processLlmRequestWithLatestAliasAddsToolToConfig() {
+    final GoogleSearchTool googleSearchTool = new GoogleSearchTool();
+    LlmRequest.Builder builder =
+        LlmRequest.builder().model("gemini-flash-latest").build().toBuilder();
+    Completable result = googleSearchTool.processLlmRequest(builder, null);
+    result.test().assertComplete();
+    assertThat(builder.build().config().get().tools().get())
+        .contains(Tool.builder().googleSearch(GoogleSearch.builder().build()).build());
+  }
+
+  @Test
+  public void processLlmRequestWithUnsupportedModelReturnsError() {
+    final GoogleSearchTool googleSearchTool = new GoogleSearchTool();
+    LlmRequest.Builder builder = LlmRequest.builder().model("text-bison-001").build().toBuilder();
+    Completable result = googleSearchTool.processLlmRequest(builder, null);
+    result.test().assertError(IllegalArgumentException.class);
+  }
+
+  @Test
+  public void processLlmRequest_WithNullModel_ReturnsError() {
+    final GoogleSearchTool googleSearchTool = new GoogleSearchTool();
+    LlmRequest.Builder builder = LlmRequest.builder().build().toBuilder();
+    Completable result = googleSearchTool.processLlmRequest(builder, null);
+    result.test().assertError(IllegalArgumentException.class);
+  }
+
   @Test
   public void processLlmRequestWithUrlContextToolAddsToolToConfig() {
     FunctionDeclaration functionDeclaration =