feat(vertexai): Add presencePenalty and frequencyPenalty to GenerationConfig

packages/firebase_vertexai/firebase_vertexai/lib/src/api.dart

@@ -551,7 +551,9 @@ final class GenerationConfig {
       this.topP,
       this.topK,
       this.responseMimeType,
-      this.responseSchema});
+      this.responseSchema,
+      this.presencePenalty,
+      this.frequencyPenalty});
 
   /// Number of generated responses to return.
   ///
@@ -598,6 +600,12 @@ final class GenerationConfig {
   /// Note: The default value varies by model.
   final int? topK;
 
+  /// Controls the likelihood of repeating the same words or phrases already generated in the text.
+  final double? presencePenalty;
+
+  /// Controls the likelihood of repeating words, with the penalty increasing for each repetition.
+  final double? frequencyPenalty;
+
   /// Output response mimetype of the generated candidate text.
   ///
   /// Supported mimetype:
@@ -627,6 +635,10 @@ final class GenerationConfig {
           'responseMimeType': responseMimeType,
         if (responseSchema case final responseSchema?)
           'responseSchema': responseSchema,
+        if (presencePenalty case final presencePenalty?)
+          'presencePenalty': presencePenalty,
+        if (frequencyPenalty case final frequencyPenalty?)
+          'frequencyPenalty': frequencyPenalty,
       };
 }
 

packages/firebase_vertexai/firebase_vertexai/test/generation_config_test.dart

@@ -0,0 +1,83 @@
+// Copyright 2025 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.
+import 'package:firebase_core/firebase_core.dart';
+import 'package:firebase_vertexai/firebase_vertexai.dart';
+import 'package:flutter_test/flutter_test.dart';
+
+import 'mock.dart';
+import 'utils/stub_client.dart';
+
+void main() {
+  setupFirebaseVertexAIMocks();
+  // ignore: unused_local_variable
+  late FirebaseApp app;
+  setUpAll(() async {
+    // Initialize Firebase
+    app = await Firebase.initializeApp();
+  });
+  group('GenerationConfig Tests', () {
+    const defaultModelName = 'some-model';
+
+    (ClientController, GenerativeModel) createModel({
+      String modelName = defaultModelName,
+    }) {
+      final client = ClientController();
+      final model = createModelWithClient(
+          app: app,
+          model: modelName,
+          client: client.client,
+          location: 'us-central1');
+      return (client, model);
+    }
+    test('toJson method', (){
+      final generationConfig = GenerationConfig(candidateCount: 2, stopSequences: ['a'], maxOutputTokens: 10,
+      topK: 1, topP: 0.5, frequencyPenalty: 0.5, presencePenalty: 0.5);
+      final result = {
+        if (candidateCount case final candidateCount?)
+          'candidateCount': candidateCount,
+        if (stopSequences case final stopSequences?)
+          'stopSequences': stopSequences,
+        if (maxOutputTokens case final maxOutputTokens?)
+          'maxOutputTokens': maxOutputTokens,
+        if (temperature case final temperature?) 'temperature': temperature,
+        if (topP case final topP?) 'topP': topP,
+        if (topK case final topK?) 'topK': topK,
+        'presencePenalty': presencePenalty,
+        'frequencyPenalty': frequencyPenalty,
+      };
+      expect(generationConfig.toJson(), result);
+    });
+    test('Test to check if presencePenalty and frequencyPenalty is include in generateContent', () async {
+       final (client, model) = createModel();
+       final response = await client.checkRequest(
+         () => model.generateContent([Content.text('Some prompt')],
+         generationConfig: GenerationConfig(presencePenalty: 0.7, frequencyPenalty: 0.3)),
+         response: arbitraryGenerateContentResponse,
+          verifyRequest: (_,request){
+            expect(request['generationConfig'], {
+                'candidateCount': 1,
+                'stopSequences': ['a'],
+                'maxOutputTokens': 10,
+                'temperature': 0.5,
+                'topP': 0.5,
+                'topK': 1,
+                'presencePenalty' : 0.7,
+                'frequencyPenalty' : 0.3,
+              });
+          },
+       );
+
+    });
+  });
+}