firebase · rlazo · Mar 2, 2026 · Mar 2, 2026 · Mar 2, 2026 · Mar 2, 2026
diff --git a/firebase-ai/CHANGELOG.md b/firebase-ai/CHANGELOG.md
@@ -1,5 +1,6 @@
 # Unreleased
 
+- [changed] Added the `hybrid` component to request headers coming from `prefer_in_cloud` configurations (#7857)
 - [feature] Added experimental support for on-device inference (#7739)
 - [feature] Added automatic function calling support with `AutoFunctionDeclaration`.
 - [feature] Added no-argument overloads for `Tool.urlContext()` and `Tool.googleSearch()`.

diff --git a/firebase-ai/src/main/kotlin/com/google/firebase/ai/GenerativeModel.kt b/firebase-ai/src/main/kotlin/com/google/firebase/ai/GenerativeModel.kt
@@ -315,10 +315,10 @@ internal constructor(
     /**
      * Returns a [GenerativeModelProvider] that uses the cloud backend.
      *
-     * @param isFallback Whether this provider is being used as a fallback for another provider.
+     * @param isHybrid Whether this provider is being used in a hybrid configuration.
      * @return A [GenerativeModelProvider] that uses the cloud backend.
      */
-    internal fun buildCloudModelProvider(isFallback: Boolean = false): GenerativeModelProvider {
+    internal fun buildCloudModelProvider(isHybrid: Boolean = false): GenerativeModelProvider {
       return CloudGenerativeModelProvider(
         modelName = modelName,
         generationConfig = generationConfig,
@@ -332,7 +332,7 @@ internal constructor(
             apiKey,
             modelName,
             requestOptions,
-            if (isFallback) "${apiClient} hybrid" else apiClient,
+            if (isHybrid) "${apiClient} hybrid" else apiClient,
             firebaseApp,
             AppCheckHeaderProvider(
               TAG,
@@ -359,13 +359,13 @@ internal constructor(
         InferenceMode.PREFER_ON_DEVICE -> {
           FallbackGenerativeModelProvider(
             defaultModel = buildOnDeviceModelProvider(),
-            fallbackModel = buildCloudModelProvider(isFallback = true),
+            fallbackModel = buildCloudModelProvider(isHybrid = true),
             shouldFallbackInException = true
           )
         }
         InferenceMode.PREFER_IN_CLOUD ->
           FallbackGenerativeModelProvider(
-            defaultModel = buildCloudModelProvider(),
+            defaultModel = buildCloudModelProvider(isHybrid = true),
             fallbackModel = buildOnDeviceModelProvider(),
             precondition =
               NetworkStatusChecker(

diff --git a/firebase-ai/src/main/kotlin/com/google/firebase/ai/common/APIController.kt b/firebase-ai/src/main/kotlin/com/google/firebase/ai/common/APIController.kt
@@ -113,7 +113,7 @@ internal constructor(
   model: String,
   private val requestOptions: RequestOptions,
   httpEngine: HttpClientEngine,
-  private val apiClient: String,
+  internal val apiClient: String,
   private val firebaseApp: FirebaseApp,
   private val appVersion: Int = 0,
   private val googleAppId: String,

diff --git a/...ai/src/main/kotlin/com/google/firebase/ai/generativemodel/CloudGenerativeModelProvider.kt b/...ai/src/main/kotlin/com/google/firebase/ai/generativemodel/CloudGenerativeModelProvider.kt
@@ -48,7 +48,7 @@ internal class CloudGenerativeModelProvider(
   private val toolConfig: ToolConfig? = null,
   private val systemInstruction: Content? = null,
   private val generativeBackend: GenerativeBackend = GenerativeBackend.googleAI(),
-  private val controller: APIController,
+  internal val controller: APIController,
 ) : GenerativeModelProvider {
 
   override suspend fun generateContent(prompt: List<Content>): GenerateContentResponse =

diff --git a/...src/main/kotlin/com/google/firebase/ai/generativemodel/FallbackGenerativeModelProvider.kt b/...src/main/kotlin/com/google/firebase/ai/generativemodel/FallbackGenerativeModelProvider.kt
@@ -47,8 +47,8 @@ import kotlinx.coroutines.flow.onEach
  * Defaults to `true`.
  */
 internal class FallbackGenerativeModelProvider(
-  private val defaultModel: GenerativeModelProvider,
-  private val fallbackModel: GenerativeModelProvider,
+  internal val defaultModel: GenerativeModelProvider,
+  internal val fallbackModel: GenerativeModelProvider,
   private val precondition: () -> Boolean = { true },
   private val shouldFallbackInException: Boolean = true
 ) : GenerativeModelProvider {

diff --git a/firebase-ai/src/test/java/com/google/firebase/ai/GenerativeModelBuilderTests.kt b/firebase-ai/src/test/java/com/google/firebase/ai/GenerativeModelBuilderTests.kt
@@ -0,0 +1,116 @@
+/*
+ * 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
+
+import android.content.Context
+import android.net.ConnectivityManager
+import com.google.firebase.FirebaseApp
+import com.google.firebase.ai.generativemodel.CloudGenerativeModelProvider
+import com.google.firebase.ai.generativemodel.FallbackGenerativeModelProvider
+import com.google.firebase.ai.type.GenerativeBackend
+import com.google.firebase.ai.type.PublicPreviewAPI
+import io.kotest.matchers.string.shouldContain
+import io.kotest.matchers.string.shouldNotContain
+import io.kotest.matchers.types.shouldBeInstanceOf
+import io.mockk.every
+import io.mockk.mockk
+import org.junit.Before
+import org.junit.Test
+
+@OptIn(PublicPreviewAPI::class)
+internal class GenerativeModelBuilderTests {
+
+  val firebaseApp = mockk<FirebaseApp>(relaxed = true)
+
+  @Before
+  fun setUp() {
+    every { firebaseApp.options.applicationId } returns "1:12345:android:67890"
+    val context = mockk<Context>(relaxed = true)
+    val connectivityManager = mockk<ConnectivityManager>(relaxed = true)
+    every { firebaseApp.applicationContext } returns context
+    every { context.getSystemService(Context.CONNECTIVITY_SERVICE) } returns connectivityManager
+  }
+
+  @Test
+  fun `getModelProvider uses hybrid suffix in PREFER_ON_DEVICE mode`() {
+    val builder =
+      GenerativeModel.Builder(
+          modelName = "gemini-1.5-flash",
+          apiKey = "apiKey",
+          firebaseApp = firebaseApp,
+          useLimitedUseAppCheckTokens = false,
+          generativeBackend = GenerativeBackend.googleAI()
+        )
+        .apply {  }
+
+    val provider = builder.getModelProvider()
+
+    provider.shouldBeInstanceOf<FallbackGenerativeModelProvider>()
+    val fallbackModel = provider.fallbackModel
+
+    fallbackModel.shouldBeInstanceOf<CloudGenerativeModelProvider>()
+    val controller = fallbackModel.controller
+
+    val apiClient = controller.apiClient
+    apiClient shouldContain " hybrid"
+  }
+
+  @Test
+  fun `getModelProvider uses hybrid suffix in PREFER_IN_CLOUD mode`() {
+    val builder =
+      GenerativeModel.Builder(
+          modelName = "gemini-1.5-flash",
+          apiKey = "apiKey",
+          firebaseApp = firebaseApp,
+          useLimitedUseAppCheckTokens = false,
+          generativeBackend = GenerativeBackend.googleAI()
+        )
+        .apply {  }
+
+    val provider = builder.getModelProvider()
+
+    provider.shouldBeInstanceOf<FallbackGenerativeModelProvider>()
+    val defaultModel = provider.defaultModel
+
+    defaultModel.shouldBeInstanceOf<CloudGenerativeModelProvider>()
+    val controller = defaultModel.controller
+
+    val apiClient = controller.apiClient
+    apiClient shouldContain " hybrid"
+  }
+
+  @Test
+  fun `getModelProvider does NOT use hybrid suffix in ONLY_IN_CLOUD mode`() {
+    val builder =
+      GenerativeModel.Builder(
+          modelName = "gemini-1.5-flash",
+          apiKey = "apiKey",
+          firebaseApp = firebaseApp,
+          useLimitedUseAppCheckTokens = false,
+          generativeBackend = GenerativeBackend.googleAI()
+        )
+        .apply {  }
+
+    val provider = builder.getModelProvider()
+
+    provider.shouldBeInstanceOf<CloudGenerativeModelProvider>()
+    val controller = provider.controller
+
+    val apiClient = controller.apiClient
+    apiClient shouldNotContain " hybrid"
+  }
+}