diff --git a/.github/workflows/dartpad_ui.yml b/.github/workflows/dartpad_ui.yml
index 2fa455135..a079b1d61 100644
--- a/.github/workflows/dartpad_ui.yml
+++ b/.github/workflows/dartpad_ui.yml
@@ -37,3 +37,4 @@ jobs:
       - run: dart format --set-exit-if-changed .
       - run: flutter build web
       - run: flutter test
+      - run: sh ./tool/check_cycles.sh
diff --git a/pkgs/dartpad_ui/lib/model.dart b/pkgs/dartpad_ui/lib/model.dart
index b155ddd3a..5d543b8b5 100644
--- a/pkgs/dartpad_ui/lib/model.dart
+++ b/pkgs/dartpad_ui/lib/model.dart
@@ -10,6 +10,7 @@ import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:http/http.dart';
 
+import 'docs.dart';
 import 'flutter_samples.dart';
 import 'gists.dart';
 import 'samples.g.dart';
@@ -90,6 +91,8 @@ class AppModel {
   final ValueNotifier<bool> useNewDDC = ValueNotifier(false);
   final ValueNotifier<String?> currentDeltaDill = ValueNotifier(null);
 
+  DocsWidget? docsWidget;
+
   AppModel() {
     consoleNotifier.addListener(_recalcLayout);
     void updateCanReload() =>
diff --git a/pkgs/dartpad_ui/tool/check_cycles.sh b/pkgs/dartpad_ui/tool/check_cycles.sh
new file mode 100644
index 000000000..b0bd111d5
--- /dev/null
+++ b/pkgs/dartpad_ui/tool/check_cycles.sh
@@ -0,0 +1,18 @@
+#!/bin/bash
+
+# Copyright 2023 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# Runs `analyze` for all code in the repo.
+
+# Fast fail the script on failures.
+set -ex
+
+# The directory that this script is located in.
+TOOL_DIR=`dirname "$0"`
+
+cd $TOOL_DIR/..
+dart pub global activate layerlens
+layerlens --path . --fail-on-cycles
+cd -