feat: add language config options to Chrome plugin

Author: kevmoo

packages/genkit_chrome/lib/src/chrome_interop.dart

@@ -23,7 +23,7 @@ extension type LanguageModelFactory._(JSObject _) implements JSObject {
   /// Returns the availability of the language model.
   ///
   /// Returns a promise that resolves to "readily", "after-download", or "no".
-  external JSPromise<JSString> availability();
+  external JSPromise<JSString> availability([LanguageModelOptions? options]);
 
   /// Creates a new session with the language model.
   external JSPromise<LanguageModel> create([LanguageModelOptions? options]);
@@ -49,6 +49,8 @@ extension type LanguageModelOptions._(JSObject _) implements JSObject {
     num? topK,
     String? systemPrompt,
     List<LanguageModelInitialPrompt>? initialPrompts,
+    List<LanguageModelExpectedInput>? expectedInputs,
+    List<LanguageModelExpectedOutput>? expectedOutputs,
   }) {
     final options = JSObject();
     if (temperature != null) options['temperature'] = temperature.toJS;
@@ -57,13 +59,37 @@ extension type LanguageModelOptions._(JSObject _) implements JSObject {
     if (initialPrompts != null && initialPrompts.isNotEmpty) {
       options['initialPrompts'] = initialPrompts.toJS;
     }
+    if (expectedInputs != null && expectedInputs.isNotEmpty) {
+      options['expectedInputs'] = expectedInputs.toJS;
+    }
+    if (expectedOutputs != null && expectedOutputs.isNotEmpty) {
+      options['expectedOutputs'] = expectedOutputs.toJS;
+    }
     return options as LanguageModelOptions;
   }
 
   external num? get temperature;
   external num? get topK;
   external String? get systemPrompt;
-  external JSArray<LanguageModelInitialPrompt> get initialPrompts;
+  external JSArray<LanguageModelInitialPrompt>? get initialPrompts;
+  external JSArray<LanguageModelExpectedInput>? get expectedInputs;
+  external JSArray<LanguageModelExpectedOutput>? get expectedOutputs;
+}
+
+@JS()
+extension type LanguageModelExpectedInput._(JSObject _) implements JSObject {
+  external factory LanguageModelExpectedInput({
+    String type,
+    JSArray<JSString>? languages,
+  });
+}
+
+@JS()
+extension type LanguageModelExpectedOutput._(JSObject _) implements JSObject {
+  external factory LanguageModelExpectedOutput({
+    String type,
+    JSArray<JSString>? languages,
+  });
 }
 
 @JS()

packages/genkit_chrome/lib/src/chrome_model.dart

@@ -49,8 +49,6 @@ class ChromeModel extends Model<LanguageModelOptions> {
         status: StatusCodes.INVALID_ARGUMENT,
       );
     }
-    // Availability check
-    await _ensureAvailability();
 
     final config = req.config ?? const {};
     final systemPrompt =
@@ -80,8 +78,17 @@ class ChromeModel extends Model<LanguageModelOptions> {
       temperature: config['temperature'] as num? ?? defaultOptions?.temperature,
       topK: config['topK'] as num? ?? defaultOptions?.topK,
       initialPrompts: initialPrompts,
+      expectedInputs:
+          _parseExpectedInputs(config) ??
+          defaultOptions?.expectedInputs?.toDart,
+      expectedOutputs:
+          _parseExpectedOutputs(config) ??
+          defaultOptions?.expectedOutputs?.toDart,
     );
 
+    // Availability check
+    await _ensureAvailability(options);
+
     final session = await _languageModel.create(options).toDart;
 
     try {
@@ -134,18 +141,15 @@ class ChromeModel extends Model<LanguageModelOptions> {
   }
 }
 
-bool _availabilityChecked = false;
-
-Future<void> _ensureAvailability() async {
-  if (_availabilityChecked) return;
-  final availability = (await _languageModel.availability().toDart).toDart;
+Future<void> _ensureAvailability([LanguageModelOptions? options]) async {
+  final availability =
+      (await _languageModel.availability(options).toDart).toDart;
   if (availability == 'no') {
     throw GenkitException(
       'Chrome AI is not available.',
       status: StatusCodes.UNAVAILABLE,
     );
   }
-  _availabilityChecked = true;
 }
 
 LanguageModelFactory get _languageModel {
@@ -164,3 +168,48 @@ To enable local AI in Chrome (v128+):
   }
   return languageModelImpl!;
 }
+
+List<T>? _parseExpected<T>({
+  required Map<String, dynamic> config,
+  required String key,
+  required T Function({String type, JSArray<JSString>? languages}) constructor,
+}) {
+  final items = config[key];
+  if (items is List) {
+    return items.map((e) {
+      if (e is Map) {
+        return constructor(
+          type: e['type'] as String? ?? 'text',
+          languages: (e['languages'] as List?)
+              ?.map((l) => (l as String).toJS)
+              .toList()
+              .toJS,
+        );
+      }
+      throw ArgumentError('Invalid item in $key: $e');
+    }).toList();
+  }
+  return null;
+}
+
+List<LanguageModelExpectedInput>? _parseExpectedInputs(
+  Map<String, dynamic> config,
+) {
+  return _parseExpected(
+    config: config,
+    key: 'expectedInputs',
+    constructor: ({String type = '', JSArray<JSString>? languages}) =>
+        LanguageModelExpectedInput(type: type, languages: languages),
+  );
+}
+
+List<LanguageModelExpectedOutput>? _parseExpectedOutputs(
+  Map<String, dynamic> config,
+) {
+  return _parseExpected(
+    config: config,
+    key: 'expectedOutputs',
+    constructor: ({String type = '', JSArray<JSString>? languages}) =>
+        LanguageModelExpectedOutput(type: type, languages: languages),
+  );
+}

pubspec.yaml

@@ -18,7 +18,7 @@ workspace:
   - testapps/agentic_patterns
   - testapps/ai_features
   - testapps/basic
-  - testapps/genkit_chrome_sample
+  - testapps/chrome_example
   - testapps/mcp_server
 
 dev_dependencies:

testapps/genkit_chrome_sample/README.md testapps/chrome_example/README.mdtestapps/genkit_chrome_sample/README.md renamed to testapps/chrome_example/README.md

@@ -216,7 +216,8 @@
         }
 
         input[type="number"], 
-        #settings-panel textarea {
+        #settings-panel textarea,
+        #settings-panel select {
             padding: 8px;
             border: 1px solid #ddd;
             border-radius: 8px;
@@ -285,6 +286,28 @@ <h1>Genkit Chrome Sample</h1>
                         <input type="number" id="topK" min="1" step="1" placeholder="default">
                     </div>
                 </div>
+                <div class="setting-group">
+                    <label for="expectedInputLanguages">
+                        Expected Input Languages
+                        <span class="help-icon" title="Select expected input languages">?</span>
+                    </label>
+                    <select id="expectedInputLanguages" multiple size="3">
+                        <option value="en" selected>English (en)</option>
+                        <option value="es">Spanish (es)</option>
+                        <option value="ja">Japanese (ja)</option>
+                    </select>
+                </div>
+                <div class="setting-group">
+                    <label for="expectedOutputLanguages">
+                        Expected Output Languages
+                        <span class="help-icon" title="Select expected output languages">?</span>
+                    </label>
+                    <select id="expectedOutputLanguages" multiple size="3">
+                        <option value="en" selected>English (en)</option>
+                        <option value="es">Spanish (es)</option>
+                        <option value="ja">Japanese (ja)</option>
+                    </select>
+                </div>
                 <div id="validation-error" class="validation-error"></div>
             </div>
         </details>

testapps/genkit_chrome_sample/build.yaml testapps/chrome_example/build.yamltestapps/genkit_chrome_sample/build.yaml renamed to testapps/chrome_example/build.yaml

@@ -158,6 +158,12 @@ final _systemPromptInput =
 final _temperatureInput =
     web.document.querySelector('#temperature') as web.HTMLInputElement;
 final _topKInput = web.document.querySelector('#topK') as web.HTMLInputElement;
+final _expectedInputLanguages =
+    web.document.querySelector('#expectedInputLanguages')
+        as web.HTMLSelectElement;
+final _expectedOutputLanguages =
+    web.document.querySelector('#expectedOutputLanguages')
+        as web.HTMLSelectElement;
 
 final List<Message> _history = [];
 
@@ -189,6 +195,17 @@ Future<void> _submit(Genkit ai) async {
     final systemPrompt = _systemPromptInput.value.trim();
     final temperature = double.tryParse(_temperatureInput.value);
     final topK = int.tryParse(_topKInput.value);
+    List<String> parseSelectedLangs(web.HTMLSelectElement selectElement) {
+      final selected = <String>[];
+      final options = selectElement.selectedOptions;
+      for (var i = 0; i < options.length; i++) {
+        selected.add((options.item(i) as web.HTMLOptionElement).value);
+      }
+      return selected;
+    }
+
+    final inputLangs = parseSelectedLangs(_expectedInputLanguages);
+    final outputLangs = parseSelectedLangs(_expectedOutputLanguages);
 
     // Update system prompt in history if it changed or is new
     // For simplicity in this sample, we'll just prepend it if it exists
@@ -207,6 +224,12 @@ Future<void> _submit(Genkit ai) async {
       if (topK != null && _defaultTopK != null && topK != _defaultTopK) {
         settingsList.add('Top K: $topK');
       }
+      if (inputLangs.isNotEmpty) {
+        settingsList.add('Input Langs: ${inputLangs.join(", ")}');
+      }
+      if (outputLangs.isNotEmpty) {
+        settingsList.add('Output Langs: ${outputLangs.join(", ")}');
+      }
 
       final contentDiv = _appendMessage(
         'Model',
@@ -229,6 +252,14 @@ Future<void> _submit(Genkit ai) async {
             if (systemPrompt.isNotEmpty) 'systemPrompt': systemPrompt,
             'temperature': ?temperature,
             'topK': ?topK,
+            if (inputLangs.isNotEmpty)
+              'expectedInputs': [
+                {'type': 'text', 'languages': inputLangs},
+              ],
+            if (outputLangs.isNotEmpty)
+              'expectedOutputs': [
+                {'type': 'text', 'languages': outputLangs},
+              ],
           },
           onChunk: (chunk) {
             if (buffer.isEmpty) {