Mila extend header custom options

ai-logic/firebase-ai/api.txt

@@ -273,6 +273,7 @@ package com.google.firebase.ai.java {
     method public static final com.google.firebase.ai.java.LiveSessionFutures from(com.google.firebase.ai.type.LiveSession session);
     method public abstract org.reactivestreams.Publisher<com.google.firebase.ai.type.LiveServerMessage> receive();
     method public abstract com.google.common.util.concurrent.ListenableFuture<kotlin.Unit> send(com.google.firebase.ai.type.Content content);
+    method public abstract com.google.common.util.concurrent.ListenableFuture<kotlin.Unit> send(com.google.firebase.ai.type.Content content, boolean turnComplete);
     method public abstract com.google.common.util.concurrent.ListenableFuture<kotlin.Unit> send(String text);
     method public abstract com.google.common.util.concurrent.ListenableFuture<kotlin.Unit> sendAudioRealtime(com.google.firebase.ai.type.InlineData audio);
     method public abstract com.google.common.util.concurrent.ListenableFuture<kotlin.Unit> sendFunctionResponse(java.util.List<com.google.firebase.ai.type.FunctionResponsePart> functionList);
@@ -1441,6 +1442,11 @@ package com.google.firebase.ai.type {
     ctor public RequestOptions(long timeoutInMillis = 180.seconds.inWholeMilliseconds, int autoFunctionCallingTurnLimit = 10);
   }
 
+  public final class RequestOptionsFactory {
+    method public com.google.firebase.ai.type.RequestOptions createWithCustomHeader(com.google.firebase.ai.type.RequestOptions baseOptions, String customApiClientHeader);
+    field public static final com.google.firebase.ai.type.RequestOptionsFactory INSTANCE;
+  }
+
   public final class RequestTimeoutException extends com.google.firebase.ai.type.FirebaseAIException {
   }
 

ai-logic/firebase-ai/src/main/kotlin/com/google/firebase/ai/GenerativeModel.kt

@@ -328,6 +328,14 @@ internal constructor(
      * @return A [GenerativeModelProvider] that uses the cloud backend.
      */
     internal fun buildCloudModelProvider(isHybrid: Boolean = false): GenerativeModelProvider {
+      var finalApiClient = apiClient
+      if (!requestOptions.customApiClientHeader.isNullOrEmpty()) {
+        finalApiClient = "$finalApiClient ${requestOptions.customApiClientHeader}"
+      }
+      if (isHybrid) {
+        finalApiClient = "$finalApiClient hybrid"
+      }
+
       return CloudGenerativeModelProvider(
         modelName = modelName,
         generationConfig = generationConfig,
@@ -341,7 +349,7 @@ internal constructor(
             apiKey,
             modelName,
             requestOptions,
-            if (isHybrid) "${apiClient} hybrid" else apiClient,
+            finalApiClient,
             firebaseApp,
             AppCheckHeaderProvider(
               TAG,

ai-logic/firebase-ai/src/main/kotlin/com/google/firebase/ai/LiveGenerativeModel.kt

@@ -92,7 +92,10 @@ internal constructor(
       apiKey,
       modelName,
       requestOptions,
-      "gl-kotlin/${KotlinVersion.CURRENT}-ai fire/${BuildConfig.VERSION_NAME}",
+      "gl-kotlin/${KotlinVersion.CURRENT}-ai fire/${BuildConfig.VERSION_NAME}".let { base ->
+        if (requestOptions.customApiClientHeader.isNullOrEmpty()) base
+        else "$base ${requestOptions.customApiClientHeader}"
+      },
       firebaseApp,
       AppCheckHeaderProvider(
         TAG,

ai-logic/firebase-ai/src/main/kotlin/com/google/firebase/ai/TemplateGenerativeModel.kt

@@ -78,7 +78,10 @@ internal constructor(
       apiKey,
       "",
       requestOptions,
-      "gl-kotlin/${KotlinVersion.CURRENT}-ai fire/${BuildConfig.VERSION_NAME}",
+      "gl-kotlin/${KotlinVersion.CURRENT}-ai fire/${BuildConfig.VERSION_NAME}".let { base ->
+        if (requestOptions.customApiClientHeader.isNullOrEmpty()) base
+        else "$base ${requestOptions.customApiClientHeader}"
+      },
       firebaseApp,
       AppCheckHeaderProvider(
         TAG,

ai-logic/firebase-ai/src/main/kotlin/com/google/firebase/ai/type/RequestOptions.kt

@@ -27,7 +27,8 @@ internal constructor(
   internal val timeout: Duration,
   internal val endpoint: String = "https://firebasevertexai.googleapis.com",
   internal val apiVersion: String = "v1beta",
-  internal val autoFunctionCallingTurnLimit: Int
+  internal val autoFunctionCallingTurnLimit: Int,
+  internal val customApiClientHeader: String? = null
 ) {
 
   /**
@@ -39,9 +40,10 @@ internal constructor(
   @JvmOverloads
   public constructor(
     timeoutInMillis: Long = 180.seconds.inWholeMilliseconds,
-    autoFunctionCallingTurnLimit: Int = 10
+    autoFunctionCallingTurnLimit: Int = 10,
   ) : this(
     timeout = timeoutInMillis.toDuration(DurationUnit.MILLISECONDS),
-    autoFunctionCallingTurnLimit = autoFunctionCallingTurnLimit
+    autoFunctionCallingTurnLimit = autoFunctionCallingTurnLimit,
+    customApiClientHeader = null
   )
 }

ai-logic/firebase-ai/src/main/kotlin/com/google/firebase/ai/type/RequestOptionsFactory.kt

@@ -0,0 +1,36 @@
+/*
+ * Copyright 2026 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.google.firebase.ai.type
+
+/**
+ * Factory for creating [RequestOptions] with custom configurations. This is primarily intended for
+ * use by wrapper libraries and internal tools.
+ */
+public object RequestOptionsFactory {
+  public fun createWithCustomHeader(
+    baseOptions: RequestOptions,
+    customApiClientHeader: String
+  ): RequestOptions {
+    return RequestOptions(
+      timeout = baseOptions.timeout,
+      endpoint = baseOptions.endpoint,
+      apiVersion = baseOptions.apiVersion,
+      autoFunctionCallingTurnLimit = baseOptions.autoFunctionCallingTurnLimit,
+      customApiClientHeader = customApiClientHeader
+    )
+  }
+}