diff --git a/apps/wolf_3d_cli/bin/main.dart b/apps/wolf_3d_cli/bin/main.dart
index 6ad66ef..57ec2dc 100644
--- a/apps/wolf_3d_cli/bin/main.dart
+++ b/apps/wolf_3d_cli/bin/main.dart
@@ -7,11 +7,11 @@ library;
 import 'dart:io';
 
 import 'package:args/args.dart';
-import 'package:wolf_3d_cli/cli_game_loop.dart';
 import 'package:wolf_3d_dart/wolf_3d_audio.dart';
 import 'package:wolf_3d_dart/wolf_3d_data.dart';
 import 'package:wolf_3d_dart/wolf_3d_data_types.dart';
 import 'package:wolf_3d_dart/wolf_3d_engine.dart';
+import 'package:wolf_3d_dart/wolf_3d_host.dart';
 import 'package:wolf_3d_dart/wolf_3d_input.dart';
 
 /// Restores terminal state before exiting the process with [code].
diff --git a/apps/wolf_3d_cli/lib/cli_renderer_settings_persistence.dart b/apps/wolf_3d_cli/lib/cli_renderer_settings_persistence.dart
deleted file mode 100644
index cafed69..0000000
--- a/apps/wolf_3d_cli/lib/cli_renderer_settings_persistence.dart
+++ /dev/null
@@ -1,58 +0,0 @@
-/// CLI host adapter for persisting renderer settings to a local file.
-library;
-
-import 'dart:io';
-
-import 'package:wolf_3d_dart/wolf_3d_engine.dart';
-
-/// Persists [WolfRendererSettings] as JSON to a local file.
-///
-/// The default path is `~/.wolf3d_cli_settings.json`.
-/// An alternative [filePath] can be supplied at construction time.
-class CliRendererSettingsPersistence extends RendererSettingsPersistence
-    with JsonRendererSettingsPersistence {
-  CliRendererSettingsPersistence({String? filePath})
-    : _filePath = filePath ?? '${_platformConfigDir()}/settings.json';
-
-  final String _filePath;
-
-  @override
-  Future<String?> readRaw() async {
-    try {
-      final File f = File(_filePath);
-      if (!f.existsSync()) {
-        return null;
-      }
-      return await f.readAsString();
-    } catch (_) {
-      return null;
-    }
-  }
-
-  @override
-  Future<void> writeRaw(String json) async {
-    try {
-      await File(_filePath).writeAsString(json, flush: true);
-    } catch (_) {
-      // Best-effort; never crash the loop on a write failure.
-    }
-  }
-}
-
-String _platformConfigDir() {
-  if (Platform.isLinux) {
-    final String xdg = Platform.environment['XDG_CONFIG_HOME'] ?? '';
-    final String home = Platform.environment['HOME'] ?? '.';
-    return xdg.isNotEmpty ? '$xdg/wolf3d' : '$home/.config/wolf3d';
-  }
-  if (Platform.isMacOS) {
-    final String home = Platform.environment['HOME'] ?? '.';
-    return '$home/Library/Application Support/wolf3d';
-  }
-  if (Platform.isWindows) {
-    final String appData = Platform.environment['APPDATA'] ?? '.';
-    return '$appData/wolf3d';
-  }
-  final String home = Platform.environment['HOME'] ?? '.';
-  return '$home/.config/wolf3d';
-}
diff --git a/apps/wolf_3d_cli/lib/cli_save_game_persistence.dart b/apps/wolf_3d_cli/lib/cli_save_game_persistence.dart
deleted file mode 100644
index 0f3f168..0000000
--- a/apps/wolf_3d_cli/lib/cli_save_game_persistence.dart
+++ /dev/null
@@ -1,84 +0,0 @@
-library;
-
-import 'dart:io';
-import 'dart:typed_data';
-
-import 'package:wolf_3d_dart/wolf_3d_data_types.dart';
-import 'package:wolf_3d_dart/wolf_3d_engine.dart';
-
-/// CLI host adapter for slot-based game save persistence.
-///
-/// Files are stored under `~/.wolf3d_saves` by default and named
-/// `SAVEGAM{slot}.{ext}` where `{ext}` follows the active game version.
-class CliSaveGamePersistence implements SaveGamePersistence {
-  CliSaveGamePersistence({String? directoryPath})
-    : _directoryPath = directoryPath ?? '${_platformConfigDir()}/saves';
-
-  final String _directoryPath;
-
-  @override
-  Future<Uint8List?> load({
-    required int slot,
-    required GameVersion version,
-  }) async {
-    try {
-      final File file = File(_slotPath(slot, version));
-      if (!file.existsSync()) {
-        return null;
-      }
-      return await file.readAsBytes();
-    } catch (_) {
-      return null;
-    }
-  }
-
-  @override
-  Future<bool> exists({
-    required int slot,
-    required GameVersion version,
-  }) async {
-    try {
-      final File file = File(_slotPath(slot, version));
-      return file.existsSync() && file.lengthSync() > 0;
-    } catch (_) {
-      return false;
-    }
-  }
-
-  @override
-  Future<void> save({
-    required int slot,
-    required GameVersion version,
-    required Uint8List bytes,
-  }) async {
-    final Directory dir = Directory(_directoryPath);
-    if (!dir.existsSync()) {
-      await dir.create(recursive: true);
-    }
-
-    await File(_slotPath(slot, version)).writeAsBytes(bytes, flush: true);
-  }
-
-  String _slotPath(int slot, GameVersion version) {
-    final String normalizedSlot = slot.clamp(0, 9).toString();
-    return '$_directoryPath/SAVEGAM$normalizedSlot.${version.fileExtension}';
-  }
-}
-
-String _platformConfigDir() {
-  if (Platform.isLinux) {
-    final String xdg = Platform.environment['XDG_CONFIG_HOME'] ?? '';
-    final String home = Platform.environment['HOME'] ?? '.';
-    return xdg.isNotEmpty ? '$xdg/wolf3d' : '$home/.config/wolf3d';
-  }
-  if (Platform.isMacOS) {
-    final String home = Platform.environment['HOME'] ?? '.';
-    return '$home/Library/Application Support/wolf3d';
-  }
-  if (Platform.isWindows) {
-    final String appData = Platform.environment['APPDATA'] ?? '.';
-    return '$appData/wolf3d';
-  }
-  final String home = Platform.environment['HOME'] ?? '.';
-  return '$home/.config/wolf3d';
-}
diff --git a/packages/wolf_3d_dart/lib/src/host/cli_game_loop.dart b/packages/wolf_3d_dart/lib/src/host/cli_game_loop.dart
new file mode 100644
index 0000000..496f5dc
--- /dev/null
+++ b/packages/wolf_3d_dart/lib/src/host/cli_game_loop.dart
@@ -0,0 +1,3 @@
+library;
+
+export 'cli_game_loop_stub.dart' if (dart.library.io) 'cli_game_loop_io.dart';
diff --git a/apps/wolf_3d_cli/lib/cli_game_loop.dart b/packages/wolf_3d_dart/lib/src/host/cli_game_loop_io.dart
similarity index 99%
rename from apps/wolf_3d_cli/lib/cli_game_loop.dart
rename to packages/wolf_3d_dart/lib/src/host/cli_game_loop_io.dart
index a49cea5..0a3e7b0 100644
--- a/apps/wolf_3d_cli/lib/cli_game_loop.dart
+++ b/packages/wolf_3d_dart/lib/src/host/cli_game_loop_io.dart
@@ -26,7 +26,6 @@ class CliGameLoop {
                'engine.input',
                'CliGameLoop requires a CliInput instance.',
              ),
-
        primaryRenderer = SixelRenderer(),
        secondaryRenderer = AsciiRenderer(
          mode: AsciiRendererMode.terminalAnsi,
diff --git a/packages/wolf_3d_dart/lib/src/host/cli_game_loop_stub.dart b/packages/wolf_3d_dart/lib/src/host/cli_game_loop_stub.dart
new file mode 100644
index 0000000..ea3b41e
--- /dev/null
+++ b/packages/wolf_3d_dart/lib/src/host/cli_game_loop_stub.dart
@@ -0,0 +1,37 @@
+/// Web-safe stub for CLI game loop APIs.
+library;
+
+import 'package:wolf_3d_dart/wolf_3d_engine.dart';
+import 'package:wolf_3d_dart/wolf_3d_input.dart';
+import 'package:wolf_3d_dart/wolf_3d_renderer.dart';
+
+class CliGameLoop {
+  CliGameLoop({
+    required this.engine,
+    required this.onExit,
+    this.persistence,
+    this.initialSettings,
+  }) : input = engine.input is CliInput
+           ? engine.input as CliInput
+           : throw ArgumentError.value(
+               engine.input,
+               'engine.input',
+               'CliGameLoop requires a CliInput instance.',
+             ),
+       primaryRenderer = SixelRenderer(),
+       secondaryRenderer = AsciiRenderer(mode: AsciiRendererMode.terminalAnsi);
+
+  final WolfEngine engine;
+  final CliRendererBackend primaryRenderer;
+  final CliRendererBackend secondaryRenderer;
+  final CliInput input;
+  final void Function(int code) onExit;
+  final RendererSettingsPersistence? persistence;
+  final WolfRendererSettings? initialSettings;
+
+  Future<void> start() {
+    throw UnsupportedError('CliGameLoop is only available on dart:io hosts.');
+  }
+
+  void stop() {}
+}
diff --git a/packages/wolf_3d_dart/lib/src/host/managers/game_persistence_manager.dart b/packages/wolf_3d_dart/lib/src/host/managers/game_persistence_manager.dart
new file mode 100644
index 0000000..c185e62
--- /dev/null
+++ b/packages/wolf_3d_dart/lib/src/host/managers/game_persistence_manager.dart
@@ -0,0 +1,42 @@
+library;
+
+import 'package:wolf_3d_dart/wolf_3d_engine.dart';
+
+/// Coordinates gameplay persistence concerns for host applications.
+class GamePersistenceManager {
+  /// Creates persistence manager dependencies with overridable adapters.
+  GamePersistenceManager({
+    RendererSettingsPersistence? rendererSettingsPersistence,
+    SaveGamePersistence? saveGamePersistence,
+  }) : rendererSettingsPersistence =
+           rendererSettingsPersistence ?? DefaultRendererSettingsPersistence(),
+       saveGamePersistence =
+           saveGamePersistence ?? DefaultSaveGamePersistence();
+
+  /// Persists and restores runtime renderer settings.
+  final RendererSettingsPersistence rendererSettingsPersistence;
+
+  /// Persists slot-based save game snapshots.
+  final SaveGamePersistence saveGamePersistence;
+
+  /// Loads previously persisted renderer settings.
+  Future<WolfRendererSettings?> loadRendererSettings() {
+    return rendererSettingsPersistence.load();
+  }
+
+  /// Loads persisted renderer settings and applies them to [engine].
+  Future<WolfRendererSettings?> restoreRendererSettings(
+    WolfEngine engine,
+  ) async {
+    final WolfRendererSettings? saved = await loadRendererSettings();
+    if (saved != null) {
+      engine.updateRendererSettings(saved);
+    }
+    return saved;
+  }
+
+  /// Saves current renderer settings.
+  Future<void> saveRendererSettings(WolfRendererSettings settings) {
+    return rendererSettingsPersistence.save(settings);
+  }
+}
diff --git a/packages/wolf_3d_dart/lib/src/host/managers/game_renderer_mode_manager.dart b/packages/wolf_3d_dart/lib/src/host/managers/game_renderer_mode_manager.dart
new file mode 100644
index 0000000..f638920
--- /dev/null
+++ b/packages/wolf_3d_dart/lib/src/host/managers/game_renderer_mode_manager.dart
@@ -0,0 +1,44 @@
+library;
+
+import 'package:wolf_3d_dart/wolf_3d_engine.dart';
+
+/// Renderer presentation mode used by host widgets.
+enum GameRendererMode {
+  /// Software pixel renderer presented via decoded framebuffer images.
+  software,
+
+  /// Text-mode renderer for debugging and retro terminal aesthetics.
+  ascii,
+
+  /// GLSL renderer with optional CRT-style post processing.
+  hardware,
+}
+
+/// Maps engine renderer settings to host renderer presentation mode.
+GameRendererMode gameRendererModeFromSettings(WolfRendererSettings settings) {
+  return switch (settings.mode) {
+    WolfRendererMode.hardware => GameRendererMode.hardware,
+    WolfRendererMode.software => GameRendererMode.software,
+    WolfRendererMode.ascii || WolfRendererMode.sixel => GameRendererMode.ascii,
+  };
+}
+
+/// Falls back to software mode when GLSL rendering is unavailable at runtime.
+void handleGlslUnavailable({
+  required bool isMounted,
+  required GameRendererMode rendererMode,
+  required WolfEngine? engine,
+}) {
+  if (!isMounted || rendererMode != GameRendererMode.hardware) {
+    return;
+  }
+
+  final WolfEngine? activeEngine = engine;
+  if (activeEngine == null) {
+    return;
+  }
+
+  activeEngine.updateRendererSettings(
+    activeEngine.rendererSettings.copyWith(mode: WolfRendererMode.software),
+  );
+}
diff --git a/packages/wolf_3d_dart/lib/src/rendering/sixel_renderer_stub.dart b/packages/wolf_3d_dart/lib/src/rendering/sixel_renderer_stub.dart
new file mode 100644
index 0000000..8975afc
--- /dev/null
+++ b/packages/wolf_3d_dart/lib/src/rendering/sixel_renderer_stub.dart
@@ -0,0 +1,25 @@
+library;
+
+import 'dart:async';
+
+import 'ascii_renderer.dart';
+
+/// Web-safe stub used when dart:io is unavailable.
+class SixelRenderer extends AsciiRenderer {
+  SixelRenderer() : super(mode: AsciiRendererMode.terminalAnsi);
+
+  bool isSixelSupported = false;
+
+  @override
+  bool isTerminalSizeSupported(int columns, int rows) => false;
+
+  @override
+  String get terminalSizeRequirement =>
+      'Sixel renderer is unavailable on this platform.';
+
+  static Future<bool> checkTerminalSixelSupport({
+    Stream<List<int>>? inputStream,
+  }) async {
+    return false;
+  }
+}
diff --git a/packages/wolf_3d_dart/lib/wolf_3d_host.dart b/packages/wolf_3d_dart/lib/wolf_3d_host.dart
new file mode 100644
index 0000000..c4ff9f8
--- /dev/null
+++ b/packages/wolf_3d_dart/lib/wolf_3d_host.dart
@@ -0,0 +1,8 @@
+/// Shared host-facing helpers for Wolf3D app shells.
+library;
+
+export 'src/host/cli_game_loop.dart' show CliGameLoop;
+export 'src/host/managers/game_persistence_manager.dart'
+    show GamePersistenceManager;
+export 'src/host/managers/game_renderer_mode_manager.dart'
+    show GameRendererMode, gameRendererModeFromSettings, handleGlslUnavailable;
diff --git a/packages/wolf_3d_dart/lib/wolf_3d_renderer.dart b/packages/wolf_3d_dart/lib/wolf_3d_renderer.dart
index 1ec8a60..07877f1 100644
--- a/packages/wolf_3d_dart/lib/wolf_3d_renderer.dart
+++ b/packages/wolf_3d_dart/lib/wolf_3d_renderer.dart
@@ -6,5 +6,6 @@ export 'src/rendering/ascii_renderer.dart'
     show AsciiRenderer, AsciiRendererMode, AsciiTheme, AsciiThemes, ColoredChar;
 export 'src/rendering/cli_renderer_backend.dart';
 export 'src/rendering/renderer_backend.dart';
-export 'src/rendering/sixel_renderer.dart';
+export 'src/rendering/sixel_renderer_stub.dart'
+    if (dart.library.io) 'src/rendering/sixel_renderer.dart';
 export 'src/rendering/software_renderer.dart';
diff --git a/packages/wolf_3d_flutter/lib/managers/game_persistence_manager.dart b/packages/wolf_3d_flutter/lib/managers/game_persistence_manager.dart
index 42a9555..834b052 100644
--- a/packages/wolf_3d_flutter/lib/managers/game_persistence_manager.dart
+++ b/packages/wolf_3d_flutter/lib/managers/game_persistence_manager.dart
@@ -1,42 +1,3 @@
 library;
 
-import 'package:wolf_3d_dart/wolf_3d_engine.dart';
-
-/// Coordinates gameplay persistence concerns for Flutter hosts.
-class GamePersistenceManager {
-  /// Creates persistence manager dependencies with overridable adapters.
-  GamePersistenceManager({
-    RendererSettingsPersistence? rendererSettingsPersistence,
-    SaveGamePersistence? saveGamePersistence,
-  }) : rendererSettingsPersistence =
-           rendererSettingsPersistence ?? DefaultRendererSettingsPersistence(),
-       saveGamePersistence =
-           saveGamePersistence ?? DefaultSaveGamePersistence();
-
-  /// Persists and restores runtime renderer settings.
-  final RendererSettingsPersistence rendererSettingsPersistence;
-
-  /// Persists slot-based save game snapshots.
-  final SaveGamePersistence saveGamePersistence;
-
-  /// Loads previously persisted renderer settings.
-  Future<WolfRendererSettings?> loadRendererSettings() {
-    return rendererSettingsPersistence.load();
-  }
-
-  /// Loads persisted renderer settings and applies them to [engine].
-  Future<WolfRendererSettings?> restoreRendererSettings(
-    WolfEngine engine,
-  ) async {
-    final WolfRendererSettings? saved = await loadRendererSettings();
-    if (saved != null) {
-      engine.updateRendererSettings(saved);
-    }
-    return saved;
-  }
-
-  /// Saves current renderer settings.
-  Future<void> saveRendererSettings(WolfRendererSettings settings) {
-    return rendererSettingsPersistence.save(settings);
-  }
-}
+export 'package:wolf_3d_dart/wolf_3d_host.dart' show GamePersistenceManager;
diff --git a/packages/wolf_3d_flutter/lib/managers/game_renderer_mode_manager.dart b/packages/wolf_3d_flutter/lib/managers/game_renderer_mode_manager.dart
index d5da436..84e4e4d 100644
--- a/packages/wolf_3d_flutter/lib/managers/game_renderer_mode_manager.dart
+++ b/packages/wolf_3d_flutter/lib/managers/game_renderer_mode_manager.dart
@@ -1,44 +1,4 @@
 library;
 
-import 'package:wolf_3d_dart/wolf_3d_engine.dart';
-
-/// Renderer presentation mode used by Flutter host widgets.
-enum GameRendererMode {
-  /// Software pixel renderer presented via decoded framebuffer images.
-  software,
-
-  /// Text-mode renderer for debugging and retro terminal aesthetics.
-  ascii,
-
-  /// GLSL renderer with optional CRT-style post processing.
-  hardware,
-}
-
-/// Maps engine renderer settings to host renderer presentation mode.
-GameRendererMode gameRendererModeFromSettings(WolfRendererSettings settings) {
-  return switch (settings.mode) {
-    WolfRendererMode.hardware => GameRendererMode.hardware,
-    WolfRendererMode.software => GameRendererMode.software,
-    WolfRendererMode.ascii || WolfRendererMode.sixel => GameRendererMode.ascii,
-  };
-}
-
-/// Falls back to software mode when GLSL rendering is unavailable at runtime.
-void handleGlslUnavailable({
-  required bool isMounted,
-  required GameRendererMode rendererMode,
-  required WolfEngine? engine,
-}) {
-  if (!isMounted || rendererMode != GameRendererMode.hardware) {
-    return;
-  }
-
-  final WolfEngine? activeEngine = engine;
-  if (activeEngine == null) {
-    return;
-  }
-
-  activeEngine.updateRendererSettings(
-    activeEngine.rendererSettings.copyWith(mode: WolfRendererMode.software),
-  );
-}
+export 'package:wolf_3d_dart/wolf_3d_host.dart'
+    show GameRendererMode, gameRendererModeFromSettings, handleGlslUnavailable;
diff --git a/packages/wolf_3d_flutter/test/app_managers_test.dart b/packages/wolf_3d_flutter/test/app_managers_test.dart
index 45c4edc..3baff3b 100644
--- a/packages/wolf_3d_flutter/test/app_managers_test.dart
+++ b/packages/wolf_3d_flutter/test/app_managers_test.dart
@@ -44,10 +44,7 @@ class _NoopAudio implements EngineAudio {
 }
 
 class _RecordingEngine extends Wolf3dFlutterEngine {
-  _RecordingEngine({required this.audio}) : super(audioBackend: audio);
-
-  @override
-  final _NoopAudio audio;
+  _RecordingEngine({required _NoopAudio audio}) : super(audioBackend: audio);
 
   int initCallCount = 0;
   String? lastDirectory;