From 4de0d8c590a96d218985c4b6bad806021390b4f2 Mon Sep 17 00:00:00 2001
From: Hemasekhar Puchuginjala <hemasekhar@google.com>
Date: Tue, 14 Jul 2026 13:58:48 +0530
Subject: [PATCH] fix: prevent dropping grounding-only responses in BaseLlmFlow

---
 .../adk/flows/llmflows/BaseLlmFlow.java       |  3 +-
 .../adk/flows/llmflows/BaseLlmFlowTest.java   | 37 +++++++++++++++++++
 2 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/core/src/main/java/com/google/adk/flows/llmflows/BaseLlmFlow.java b/core/src/main/java/com/google/adk/flows/llmflows/BaseLlmFlow.java
index 7d62c8505..91cc225f2 100644
--- a/core/src/main/java/com/google/adk/flows/llmflows/BaseLlmFlow.java
+++ b/core/src/main/java/com/google/adk/flows/llmflows/BaseLlmFlow.java
@@ -746,7 +746,8 @@ private Flowable<Event> buildPostprocessingEvents(
         && (context.runConfig().streamingMode() != StreamingMode.BIDI
             || updatedResponse.usageMetadata().isEmpty())
         && updatedResponse.inputTranscription().isEmpty()
-        && updatedResponse.outputTranscription().isEmpty()) {
+        && updatedResponse.outputTranscription().isEmpty()
+        && updatedResponse.groundingMetadata().isEmpty()) {
       return processorEvents;
     }
 
diff --git a/core/src/test/java/com/google/adk/flows/llmflows/BaseLlmFlowTest.java b/core/src/test/java/com/google/adk/flows/llmflows/BaseLlmFlowTest.java
index d25f386df..1761871e6 100644
--- a/core/src/test/java/com/google/adk/flows/llmflows/BaseLlmFlowTest.java
+++ b/core/src/test/java/com/google/adk/flows/llmflows/BaseLlmFlowTest.java
@@ -48,6 +48,7 @@
 import com.google.genai.types.FunctionCall;
 import com.google.genai.types.FunctionDeclaration;
 import com.google.genai.types.GenerateContentResponseUsageMetadata;
+import com.google.genai.types.GroundingMetadata;
 import com.google.genai.types.Part;
 import com.google.genai.types.Transcription;
 import io.opentelemetry.context.Context;
@@ -1002,4 +1003,40 @@ public void getRequestProcessorFromTools_throwsOnUnsupportedType() {
         .hasMessageThat()
         .contains("Object in tools list is not of a supported type: java.lang.String");
   }
+
+  @Test
+  public void postprocess_onlyGroundingMetadata_returnsEvent() {
+    GroundingMetadata groundingMetadata =
+        GroundingMetadata.builder()
+            .webSearchQueries(ImmutableList.of("What is the capital of France?"))
+            .build();
+
+    LlmResponse llmResponse = LlmResponse.builder().groundingMetadata(groundingMetadata).build();
+
+    InvocationContext invocationContext =
+        createInvocationContext(createTestAgent(createTestLlm(llmResponse)));
+    BaseLlmFlow baseLlmFlow = createBaseLlmFlowWithoutProcessors();
+    Event baseEvent =
+        Event.builder()
+            .invocationId(invocationContext.invocationId())
+            .author(invocationContext.agent().name())
+            .build();
+
+    // 2. Act: Run the post-processor
+    List<Event> events =
+        baseLlmFlow
+            .postprocess(
+                invocationContext,
+                baseEvent,
+                LlmRequest.builder().build(),
+                llmResponse,
+                Context.current())
+            .toList()
+            .blockingGet();
+
+    assertThat(events).hasSize(1);
+    Event event = getOnlyElement(events);
+    assertThat(event.content()).isEmpty();
+    assertThat(event.groundingMetadata()).hasValue(groundingMetadata);
+  }
 }