fix: remove client-side function call IDs from LlmRequest

PiperOrigin-RevId: 871928882

Author: google-genai-bot

core/src/main/java/com/google/adk/models/GeminiUtil.java

@@ -59,7 +59,9 @@ public static LlmRequest prepareGenenerateContentRequest(
    * Prepares an {@link LlmRequest} for the GenerateContent API.
    *
    * <p>This method can optionally sanitize the request and ensures that the last content part is
-   * from the user to prompt a model response. It also strips out any parts marked as "thoughts".
+   * from the user to prompt a model response. It also strips out any parts marked as "thoughts" and
+   * removes client-side function call IDs as some LLM APIs reject requests with client-side
+   * function call IDs.
    *
    * @param llmRequest The original {@link LlmRequest}.
    * @param sanitize Whether to sanitize the request to be compatible with the Gemini API backend.
@@ -70,6 +72,7 @@ public static LlmRequest prepareGenenerateContentRequest(
     if (sanitize) {
       llmRequest = sanitizeRequestForGeminiApi(llmRequest);
     }
+    llmRequest = removeClientFunctionCallId(llmRequest);
     List<Content> contents = ensureModelResponse(llmRequest.contents());
     if (stripThoughts) {
       contents = stripThoughts(contents);
@@ -136,6 +139,50 @@ public static LlmRequest sanitizeRequestForGeminiApi(LlmRequest llmRequest) {
     return requestBuilder.contents(updatedContents).build();
   }
 
+  /**
+   * Removes client-side function call IDs from the request.
+   *
+   * <p>Client-side function call IDs are internal to the ADK and should not be sent to the model.
+   * This method iterates through the contents and parts, removing the ID from any {@link
+   * com.google.genai.types.FunctionCall} or {@link com.google.genai.types.FunctionResponse} parts.
+   *
+   * @param llmRequest The request to process.
+   * @return A new {@link LlmRequest} with function call IDs removed.
+   */
+  public static LlmRequest removeClientFunctionCallId(LlmRequest llmRequest) {
+    if (llmRequest.contents().isEmpty()) {
+      return llmRequest;
+    }
+
+    ImmutableList<Content> updatedContents =
+        llmRequest.contents().stream()
+            .map(
+                content ->
+                    content.toBuilder()
+                        .parts(
+                            content.parts().orElse(ImmutableList.of()).stream()
+                                .map(GeminiUtil::removeClientFunctionCallIdFromPart)
+                                .collect(toImmutableList()))
+                        .build())
+            .collect(toImmutableList());
+
+    return llmRequest.toBuilder().contents(updatedContents).build();
+  }
+
+  private static Part removeClientFunctionCallIdFromPart(Part part) {
+    if (part.functionCall().isPresent() && part.functionCall().get().id().isPresent()) {
+      return part.toBuilder()
+          .functionCall(part.functionCall().get().toBuilder().clearId().build())
+          .build();
+    }
+    if (part.functionResponse().isPresent() && part.functionResponse().get().id().isPresent()) {
+      return part.toBuilder()
+          .functionResponse(part.functionResponse().get().toBuilder().clearId().build())
+          .build();
+    }
+    return part;
+  }
+
   /**
    * Ensures that the content is conducive to prompting a model response by ensuring the last
    * content part is from the user.
@@ -213,7 +260,7 @@ public static boolean shouldEmitAccumulatedText(LlmResponse currentLlmResponse)
   }
 
   /** Removes any `Part` that contains only a `thought` from the content list. */
-  public static List<Content> stripThoughts(List<Content> originalContents) {
+  public static ImmutableList<Content> stripThoughts(List<Content> originalContents) {
     return originalContents.stream()
         .map(
             content -> {

core/src/test/java/com/google/adk/models/GeminiUtilTest.java

@@ -24,6 +24,8 @@
 import com.google.genai.types.Blob;
 import com.google.genai.types.Content;
 import com.google.genai.types.FileData;
+import com.google.genai.types.FunctionCall;
+import com.google.genai.types.FunctionResponse;
 import com.google.genai.types.GenerateContentConfig;
 import com.google.genai.types.Part;
 import java.util.Arrays;
@@ -451,6 +453,43 @@ public void prepareGenenerateContentRequest_emptyRequest_returnsRequestWithConti
         .inOrder();
   }
 
+  @Test
+  public void removeClientFunctionCallId_stripsIds() {
+    Part partWithFunctionCall =
+        Part.builder()
+            .functionCall(
+                FunctionCall.builder()
+                    .name("foo")
+                    .id("id1")
+                    .args(ImmutableMap.of("key", "value"))
+                    .build())
+            .build();
+    Part partWithFunctionResponse =
+        Part.builder()
+            .functionResponse(
+                FunctionResponse.builder()
+                    .name("bar")
+                    .id("id2")
+                    .response(ImmutableMap.of("key", "value"))
+                    .build())
+            .build();
+    LlmRequest request = toRequest(partWithFunctionCall, partWithFunctionResponse);
+
+    LlmRequest result = GeminiUtil.removeClientFunctionCallId(request);
+
+    assertThat(result.contents()).hasSize(1);
+    assertThat(result.contents().get(0).parts()).isPresent();
+    assertThat(result.contents().get(0).parts().get()).hasSize(2);
+    Part resultPart1 = result.contents().get(0).parts().get().get(0);
+    assertThat(resultPart1.functionCall()).isPresent();
+    assertThat(resultPart1.functionCall().get().id()).isEmpty();
+    assertThat(resultPart1.functionCall().get().name()).hasValue("foo");
+    Part resultPart2 = result.contents().get(0).parts().get().get(1);
+    assertThat(resultPart2.functionResponse()).isPresent();
+    assertThat(resultPart2.functionResponse().get().id()).isEmpty();
+    assertThat(resultPart2.functionResponse().get().name()).hasValue("bar");
+  }
+
   private static Content toContent(Part... parts) {
     return Content.builder().parts(ImmutableList.copyOf(parts)).build();
   }