flutter · andrewkolos · May 26, 2026 · May 26, 2026 · May 26, 2026 · May 26, 2026
diff --git a/coverage_baseline.yaml b/coverage_baseline.yaml
@@ -7,7 +7,7 @@ dev_tools/catalog_gallery: 52.91
 dev_tools/composer: 20.49
 packages/a2ui_core: 76.30
 packages/genai_primitives: 100.00
-packages/genui: 79.71
+packages/genui: 79.38
 packages/genui_a2a: 91.37
 packages/json_schema_builder: 79.09
 tool/e2e: 100.00

diff --git a/dev_tools/catalog_gallery/lib/sample_parser.dart b/dev_tools/catalog_gallery/lib/sample_parser.dart
@@ -4,14 +4,14 @@
 
 import 'dart:convert';
 
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:file/file.dart';
-import 'package:genui/genui.dart';
 import 'package:yaml/yaml.dart';
 
 class Sample {
   final String name;
   final String description;
-  final Stream<A2uiMessage> messages;
+  final Stream<core.A2uiMessage> messages;
 
   Sample({
     required this.name,
@@ -52,14 +52,14 @@ class SampleParser {
     final String name = header['name'] as String? ?? 'Untitled Sample';
     final String description = header['description'] as String? ?? '';
 
-    final Stream<A2uiMessage> messages = Stream.fromIterable(
+    final Stream<core.A2uiMessage> messages = Stream.fromIterable(
       const LineSplitter()
           .convert(jsonlBody)
           .where((line) => line.trim().isNotEmpty)
           .map((line) {
             final dynamic json = jsonDecode(line);
             if (json is Map<String, dynamic>) {
-              return A2uiMessage.fromJson(json);
+              return core.A2uiMessage.fromJson(json);
             }
             throw FormatException('Invalid JSON line: $line');
           }),

diff --git a/dev_tools/catalog_gallery/lib/samples_view.dart b/dev_tools/catalog_gallery/lib/samples_view.dart
@@ -4,6 +4,7 @@
 
 import 'dart:async';
 
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:file/file.dart';
 import 'package:file/local.dart';
 import 'package:flutter/material.dart';
@@ -35,7 +36,7 @@ class _SamplesViewState extends State<SamplesView> {
   final List<String> _surfaceIds = [];
   int _currentSurfaceIndex = 0;
   StreamSubscription<SurfaceUpdate>? _surfaceSubscription;
-  StreamSubscription<A2uiMessage>? _messageSubscription;
+  StreamSubscription<core.A2uiMessage>? _messageSubscription;
 
   @override
   void initState() {

diff --git a/dev_tools/catalog_gallery/pubspec.yaml b/dev_tools/catalog_gallery/pubspec.yaml
@@ -13,6 +13,7 @@ environment:
 resolution: workspace
 
 dependencies:
+  a2ui_core: ^0.0.1-wip002
   args: ^2.7.0
   file: ^7.0.1
   flutter:

diff --git a/dev_tools/catalog_gallery/test/layout_test.dart b/dev_tools/catalog_gallery/test/layout_test.dart
@@ -4,6 +4,7 @@
 
 import 'dart:io';
 
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:catalog_gallery/sample_parser.dart';
 import 'package:file/file.dart' as file_pkg;
 import 'package:flutter/material.dart';
@@ -38,13 +39,13 @@ void main() {
       catalogs: [BasicCatalogItems.asCatalog()],
     );
 
-    await for (final A2uiMessage message in sample.messages) {
+    await for (final core.A2uiMessage message in sample.messages) {
       var messageToProcess = message;
-      if (message is CreateSurface) {
+      if (message is core.CreateSurfaceMessage) {
         // We manually inject the basic catalog since createSurface might ref
         // external URL in this test environment, we just assume the basic
         // catalog is available
-        messageToProcess = CreateSurface(
+        messageToProcess = core.CreateSurfaceMessage(
           surfaceId: message.surfaceId,
           catalogId: basicCatalogId,
           theme: message.theme,
@@ -81,7 +82,7 @@ void main() {
         catalogs: [BasicCatalogItems.asCatalog()],
       );
 
-      await for (final A2uiMessage message in sample.messages) {
+      await for (final core.A2uiMessage message in sample.messages) {
         controller.handleMessage(message);
       }
 

diff --git a/dev_tools/catalog_gallery/test/sample_parser_test.dart b/dev_tools/catalog_gallery/test/sample_parser_test.dart
@@ -2,9 +2,9 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:catalog_gallery/sample_parser.dart';
 import 'package:flutter_test/flutter_test.dart';
-import 'package:genui/genui.dart';
 
 void main() {
   test('SampleParser parses valid sample string', () async {
@@ -21,19 +21,19 @@ description: A test description
     expect(sample.name, 'Test Sample');
     expect(sample.description, 'A test description');
 
-    final List<A2uiMessage> messages = await sample.messages.toList();
+    final List<core.A2uiMessage> messages = await sample.messages.toList();
     expect(messages.length, 2);
-    expect(messages.first, isA<UpdateComponents>());
-    expect(messages.last, isA<CreateSurface>());
+    expect(messages.first, isA<core.UpdateComponentsMessage>());
+    expect(messages.last, isA<core.CreateSurfaceMessage>());
 
-    final update = messages.first as UpdateComponents;
+    final update = messages.first as core.UpdateComponentsMessage;
     expect(update.surfaceId, 'default');
     expect(update.components.length, 1);
-    expect(update.components.first.type, 'Text');
+    expect(update.components.first['component'], 'Text');
 
-    final begin = messages.last as CreateSurface;
+    final begin = messages.last as core.CreateSurfaceMessage;
     expect(begin.surfaceId, 'default');
-    // begin.root check removed as it doesn't exist in CreateSurface
+    // begin.root check removed as it doesn't exist in CreateSurfaceMessage
   });
 
   test(
@@ -48,7 +48,7 @@ description: A description
 ''';
       final Sample sample = SampleParser.parseString(sampleContent);
       expect(sample.name, 'Frontmatter Sample');
-      final List<A2uiMessage> messages = await sample.messages.toList();
+      final List<core.A2uiMessage> messages = await sample.messages.toList();
       expect(messages.length, 1);
     },
   );
@@ -61,7 +61,7 @@ description: A description
 ''';
     final Sample sample = SampleParser.parseString(sampleContent);
     expect(sample.name, 'Untitled Sample');
-    final List<A2uiMessage> messages = await sample.messages.toList();
+    final List<core.A2uiMessage> messages = await sample.messages.toList();
     expect(messages.length, 1);
   });
 

diff --git a/dev_tools/catalog_gallery/test/samples_rendering_test.dart b/dev_tools/catalog_gallery/test/samples_rendering_test.dart
@@ -4,6 +4,7 @@
 
 import 'dart:io';
 
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:catalog_gallery/sample_parser.dart';
 import 'package:file/file.dart';
 import 'package:file/local.dart';
@@ -78,7 +79,7 @@ void main() {
       );
 
       try {
-        await for (final A2uiMessage message in sample.messages) {
+        await for (final core.A2uiMessage message in sample.messages) {
           controller.handleMessage(message);
           await tester.pump();
         }

diff --git a/dev_tools/composer/lib/ai_client_transport.dart b/dev_tools/composer/lib/ai_client_transport.dart
@@ -4,6 +4,7 @@
 
 import 'dart:async';
 
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:dartantic_ai/dartantic_ai.dart' as dartantic;
 import 'package:genui/genui.dart';
 import 'package:logging/logging.dart';
@@ -20,7 +21,7 @@ class AiClientTransport implements Transport {
   final Logger _logger = Logger('AiClientTransport');
 
   @override
-  Stream<A2uiMessage> get incomingMessages => _adapter.incomingMessages;
+  Stream<core.A2uiMessage> get incomingMessages => _adapter.incomingMessages;
 
   @override
   Stream<String> get incomingText => _adapter.incomingText;

diff --git a/dev_tools/composer/lib/sample_parser.dart b/dev_tools/composer/lib/sample_parser.dart
@@ -4,15 +4,15 @@
 
 import 'dart:convert';
 
-import 'package:genui/genui.dart';
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:yaml/yaml.dart';
 
 /// A parsed sample containing metadata and a stream of A2UI messages.
 class Sample {
   final String name;
   final String description;
   final String rawJsonl;
-  final Stream<A2uiMessage> messages;
+  final Stream<core.A2uiMessage> messages;
 
   Sample({
     required this.name,
@@ -50,14 +50,14 @@ class SampleParser {
     final String name = header['name'] as String? ?? 'Untitled Sample';
     final String description = header['description'] as String? ?? '';
 
-    final Stream<A2uiMessage> messages = Stream.fromIterable(
+    final Stream<core.A2uiMessage> messages = Stream.fromIterable(
       const LineSplitter()
           .convert(jsonlBody)
           .where((line) => line.trim().isNotEmpty)
           .map((line) {
             final Object? json = jsonDecode(line);
             if (json is Map<String, Object?>) {
-              return A2uiMessage.fromJson(json);
+              return core.A2uiMessage.fromJson(json);
             }
             throw FormatException('Invalid JSON line: $line');
           }),

diff --git a/dev_tools/composer/lib/surface_editor.dart b/dev_tools/composer/lib/surface_editor.dart
@@ -5,6 +5,7 @@
 import 'dart:async';
 import 'dart:convert';
 
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:flutter/material.dart';
 import 'package:flutter_code_editor/flutter_code_editor.dart';
 import 'package:flutter_highlight/themes/vs.dart';
@@ -150,7 +151,9 @@ class _SurfaceEditorViewState extends State<SurfaceEditorView> {
     _dataModelNotifier?.removeListener(_onDataModelChanged);
     if (_surfaceIds.isEmpty) return;
 
-    final dataModel = _surfaceController.store.getDataModel(_surfaceIds.first);
+    final dataModel = _surfaceController
+        .contextFor(_surfaceIds.first)
+        .dataModel;
     _dataModelNotifier = dataModel.subscribe<Object?>(DataPath.root);
     _dataModelNotifier!.addListener(_onDataModelChanged);
   }
@@ -164,7 +167,7 @@ class _SurfaceEditorViewState extends State<SurfaceEditorView> {
     if (_surfaceIds.isEmpty) return;
 
     final surfaceId = _surfaceIds.first;
-    final dataModel = _surfaceController.store.getDataModel(surfaceId);
+    final dataModel = _surfaceController.contextFor(surfaceId).dataModel;
     final data = dataModel.getValue<Object?>(DataPath.root);
     final dataJson = const JsonEncoder.withIndent('  ').convert(data);
 
@@ -202,7 +205,7 @@ class _SurfaceEditorViewState extends State<SurfaceEditorView> {
 
         final obj = jsonDecode(trimmedChunk);
         if (obj is Map<String, Object?>) {
-          final message = A2uiMessage.fromJson(obj);
+          final message = core.A2uiMessage.fromJson(obj);
           _surfaceController.handleMessage(message);
         }
       }
@@ -227,7 +230,7 @@ class _SurfaceEditorViewState extends State<SurfaceEditorView> {
       if (parsed is Map<String, Object?>) {
         final surfaceId = _surfaceIds.first;
         _surfaceController.handleMessage(
-          A2uiMessage.fromJson({
+          core.A2uiMessage.fromJson({
             'version': kProtocolVersion,
             'updateDataModel': {
               'surfaceId': surfaceId,

diff --git a/dev_tools/composer/pubspec.yaml b/dev_tools/composer/pubspec.yaml
@@ -12,6 +12,7 @@ environment:
 resolution: workspace
 
 dependencies:
+  a2ui_core: ^0.0.1-wip002
   dartantic_ai: ^3.2.0
   flutter:
     sdk: flutter

diff --git a/docs/usage/migration/migration_0.9.1_to_0.10.0.md b/docs/usage/migration/migration_0.9.1_to_0.10.0.md
@@ -0,0 +1,72 @@
+# Migration Guide: 0.9.1 to 0.10.0
+
+`package:genui` now runs on the shared `package:a2ui_core` runtime (#811). The
+only customer-facing change is for code that **implements a custom `Transport` or
+constructs/parses A2UI messages directly** — those message types moved to
+`a2ui_core`. The default AI/transport flow, catalog widgets, and data-binding code
+are unaffected.
+
+## What you have to change
+
+### A2UI messages are now `a2ui_core` types
+
+The genui message classes (`A2uiMessage`, `CreateSurface`, `UpdateComponents`,
+`UpdateDataModel`, `DeleteSurface`) are removed. Add `a2ui_core` to your
+dependencies and use its message types. They don't collide with anything genui
+exports, so import them unprefixed with a `show` list:
+
+```dart
+// Before
+controller.handleMessage(
+  UpdateComponents(surfaceId: 's', components: [
+    Component(id: 'root', type: 'Text', properties: {'text': 'Hi'}),
+  ]),
+);
+controller.handleMessage(CreateSurface(surfaceId: 's', catalogId: 'demo'));
+
+// After
+import 'package:a2ui_core/a2ui_core.dart'
+    show CreateSurfaceMessage, UpdateComponentsMessage;
+
+controller.handleMessage(
+  UpdateComponentsMessage(surfaceId: 's', components: [
+    {'id': 'root', 'component': 'Text', 'text': 'Hi'},
+  ]),
+);
+controller.handleMessage(
+  CreateSurfaceMessage(surfaceId: 's', catalogId: 'demo'),
+);
+```
+
+- **Custom transport:** `Transport.incomingMessages` and
+  `SurfaceController.handleMessage` now use `a2ui_core`'s `A2uiMessage`. Update
+  those signatures if you implement `Transport` or drive the controller directly.
+- **Building messages:** `UpdateComponentsMessage` takes raw component JSON maps
+  (`{'id': ..., 'component': ..., ...props}`), not `Component` objects.
+- **Parsing raw JSON:** use `A2uiMessage.fromJson(json)`.
+
+### `SurfaceController.store` is removed
+
+Read a surface's data model via `SurfaceController.contextFor(id).dataModel`
+(writable, and usable before the surface is created).
+
+## Behavior you may notice
+
+- **`DataModel` writes are stricter.** Some writes that used to silently do
+  nothing now throw, e.g. writing through a path whose intermediate value isn't a
+  map or list.
+- **Malformed messages are rejected more consistently** (missing or wrong
+  version, or more than one action key in a single message).
+- **A duplicate `createSurface` for an active surface id is now an error** rather
+  than silently reusing the existing surface.
+- **`updateDataModel` with `value: null` removes the key**, the same as omitting
+  the value. Distinguishing the two is pending flutter/genui#938.
+
+## What does not change
+
+Your catalog widgets and data-binding code are untouched: `CatalogItemContext`,
+`dataContext`, the `DataModel` / `DataPath` API, the `Bound*` widgets, and the
+`SurfaceDefinition` / `Component` snapshots all keep their current shape.
+
+A follow-up (#801) will unify these with the `a2ui_core` models once the upstream
+Node Layer (A2UI#1282) lands.
diff --git a/examples/simple_chat/lib/a2ui_transport.dart b/examples/simple_chat/lib/a2ui_transport.dart
@@ -4,6 +4,7 @@
 
 import 'dart:async';
 
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:genui/genui.dart';
 
 import 'agent/agent.dart';
@@ -22,7 +23,7 @@ class SimpleChatA2aTransport implements Transport {
   final A2uiTransportAdapter _adapter = A2uiTransportAdapter();
 
   @override
-  Stream<A2uiMessage> get incomingMessages => _adapter.incomingMessages;
+  Stream<core.A2uiMessage> get incomingMessages => _adapter.incomingMessages;
 
   @override
   Stream<String> get incomingText => _adapter.incomingText;

diff --git a/examples/simple_chat/lib/chat_session.dart b/examples/simple_chat/lib/chat_session.dart
@@ -4,6 +4,7 @@
 
 import 'dart:async';
 
+import 'package:a2ui_core/a2ui_core.dart' as core;
 import 'package:flutter/foundation.dart';
 import 'package:genui/genui.dart';
 import 'package:logging/logging.dart';
@@ -190,7 +191,7 @@ class A2uiChatSession extends ChatSession {
   @override
   SurfaceController get surfaceController => _surfaceController;
 
-  late final StreamSubscription<A2uiMessage> _messageSub;
+  late final StreamSubscription<core.A2uiMessage> _messageSub;
   late final StreamSubscription<String> _textSub;
   late final StreamSubscription<ChatMessage> _submitSub;
   late final StreamSubscription<SurfaceUpdate> _surfaceSub;

diff --git a/examples/simple_chat/pubspec.yaml b/examples/simple_chat/pubspec.yaml
@@ -12,6 +12,7 @@ environment:
 resolution: workspace
 
 dependencies:
+  a2ui_core: ^0.0.1-wip002
   dartantic_ai: ^3.2.0
   flutter:
     sdk: flutter