From 75e66a2029d0e91332961bf494f546114d9c1d6c Mon Sep 17 00:00:00 2001
From: Rodrigo Lazo Paz <rlazo@google.com>
Date: Tue, 30 Sep 2025 13:52:59 -0400
Subject: [PATCH 1/2] [ALF] Deprecate `UsageMetadata` public constructor

The class was never meant to be instantiated by clients. The public
constructor is now marked as deprecated and will be removed in a
upcoming major version bump.

Additionally, the PR includes an unused parameter in the internal
version to get the code to build. It will be removed in a upcoming
change were an actual new parameter, exclusive to the internal
constructor, is added.
---
 .../google/firebase/ai/type/UsageMetadata.kt  | 22 ++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/firebase-ai/src/main/kotlin/com/google/firebase/ai/type/UsageMetadata.kt b/firebase-ai/src/main/kotlin/com/google/firebase/ai/type/UsageMetadata.kt
index 1c7d39103fb..e733445e916 100644
--- a/firebase-ai/src/main/kotlin/com/google/firebase/ai/type/UsageMetadata.kt
+++ b/firebase-ai/src/main/kotlin/com/google/firebase/ai/type/UsageMetadata.kt
@@ -30,15 +30,35 @@ import kotlinx.serialization.Serializable
  * candidates.
  * @param thoughtsTokenCount The number of tokens used by the model's internal "thinking" process.
  */
-public class UsageMetadata(
+public class UsageMetadata
+internal constructor(
   public val promptTokenCount: Int,
   public val candidatesTokenCount: Int?,
   public val totalTokenCount: Int,
   public val promptTokensDetails: List<ModalityTokenCount>,
   public val candidatesTokensDetails: List<ModalityTokenCount>,
   public val thoughtsTokenCount: Int,
+  placeholder: Unit
 ) {
 
+  @Deprecated("Not intended for public use")
+  public constructor(
+    promptTokenCount: Int,
+    candidatesTokenCount: Int?,
+    totalTokenCount: Int,
+    promptTokensDetails: List<ModalityTokenCount>,
+    candidatesTokensDetails: List<ModalityTokenCount>,
+    thoughtsTokenCount: Int
+  ) : this(
+    promptTokenCount,
+    candidatesTokenCount,
+    totalTokenCount,
+    promptTokensDetails,
+    candidatesTokensDetails,
+    thoughtsTokenCount,
+    Unit
+  )
+
   @Serializable
   internal data class Internal(
     val promptTokenCount: Int? = null,

From b5904f29e9ac12a4e506ef6d9721c5052a57f0a5 Mon Sep 17 00:00:00 2001
From: Rodrigo Lazo Paz <rlazo@google.com>
Date: Tue, 30 Sep 2025 13:54:11 -0400
Subject: [PATCH 2/2] Add changelog entry

---
 firebase-ai/CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/firebase-ai/CHANGELOG.md b/firebase-ai/CHANGELOG.md
index a38389fca7c..d694b73cce8 100644
--- a/firebase-ai/CHANGELOG.md
+++ b/firebase-ai/CHANGELOG.md
@@ -3,6 +3,7 @@
 - [changed] **Breaking Change**: Removed the `candidateCount` option from `LiveGenerationConfig`
   (#7382)
 - [changed] Added better error messages to `ServiceConnectionHandshakeFailedException` (#7412)
+- [changed] Marked the public constructor for `UsageMetadata` as deprecated (#7420)
 
 # 17.3.0