diff --git a/Controls/TopBar.xaml b/Controls/TopBar.xaml
index a99e39d..5635797 100644
--- a/Controls/TopBar.xaml
+++ b/Controls/TopBar.xaml
@@ -109,24 +109,42 @@
             <!-- IDLE: the mode switch + the action(s) of the armed world. The three
                  controls share one height (build 77 feedback) so they read as one
                  family — segments host, Start/Go Live, and Test all sit at 32. -->
+            <!-- THE OUTPUT STAGE (creator ruling 2026-11-12): which single output, and the one action
+                 that starts it. Appears only in the Record / Go Live world and only while nothing is
+                 running — a live session cannot change its output. YouTube and Local MP4 are one axis,
+                 so the two switches are radio-exclusive in the view model, not by luck here. -->
             <StackPanel Orientation="Horizontal"
-                        Visibility="{Binding ShowIdleWorld, Converter={StaticResource BoolToVis}}">
+                        Visibility="{Binding ShowOutputStage, Converter={StaticResource BoolToVis}}">
+                <TextBlock Text="Output" FontSize="12" FontWeight="Bold" VerticalAlignment="Center"
+                           Foreground="{StaticResource Brush.OnSurfaceVariant}" Margin="0,0,8,0"/>
                 <Border Background="{StaticResource Brush.SurfaceContainerLowest}" CornerRadius="4" Padding="2" Height="32" VerticalAlignment="Center">
                     <StackPanel Orientation="Horizontal">
                         <ToggleButton Style="{StaticResource RecordPillToggle}"
-                                      IsChecked="{Binding RecordPillOn}">
-                            <!-- the label follows the pill's own foreground: muted when armed-off,
-                                 dark on red when armed (SegmentLabel pins its own colour) -->
-                            <TextBlock Text="REC" FontSize="12" FontWeight="Bold" VerticalAlignment="Center"
-                                       Foreground="{Binding Foreground, RelativeSource={RelativeSource AncestorType=ToggleButton}}"/>
+                                      IsChecked="{Binding OnAirPillOn}">
+                            <StackPanel Orientation="Horizontal">
+                                <Path Width="14" Height="14" Stretch="Uniform" VerticalAlignment="Center"
+                                      Fill="{Binding Foreground, RelativeSource={RelativeSource AncestorType=ToggleButton}}"
+                                      Data="M23.498 6.186a3.016 3.016 0 0 0-2.122-2.136C19.505 3.545 12 3.545 12 3.545s-7.505 0-9.377.505A3.017 3.017 0 0 0 .502 6.186C0 8.07 0 12 0 12s0 3.93.502 5.814a3.016 3.016 0 0 0 2.122 2.136c1.871.505 9.376.505 9.376.505s7.505 0 9.377-.505a3.015 3.015 0 0 0 2.122-2.136C24 15.93 24 12 24 12s0-3.93-.502-5.814zM9.545 15.568V8.432L15.818 12l-6.273 3.568z"/>
+                                <TextBlock Text="YouTube" FontSize="12" FontWeight="Bold" Margin="6,0,0,0"
+                                           VerticalAlignment="Center"
+                                           Foreground="{Binding Foreground, RelativeSource={RelativeSource AncestorType=ToggleButton}}"/>
+                            </StackPanel>
                         </ToggleButton>
                         <ToggleButton Style="{StaticResource RecordPillToggle}"
-                                      IsChecked="{Binding OnAirPillOn}">
-                            <TextBlock Text="ON-AIR" FontSize="12" FontWeight="Bold" VerticalAlignment="Center"
-                                       Foreground="{Binding Foreground, RelativeSource={RelativeSource AncestorType=ToggleButton}}"/>
+                                      IsChecked="{Binding RecordPillOn}">
+                            <StackPanel Orientation="Horizontal">
+                                <Path Width="14" Height="14" Stretch="Uniform" VerticalAlignment="Center"
+                                      Fill="{Binding Foreground, RelativeSource={RelativeSource AncestorType=ToggleButton}}"
+                                      Data="M12,2a10,10 0 1,0 0,20a10,10 0 1,0 0,-20zM12,4a8,8 0 1,1 0,16a8,8 0 1,1 0,-16zM12,7.5a4.5,4.5 0 1,1 0,9a4.5,4.5 0 1,1 0,-9z"/>
+                                <TextBlock Text="Local MP4" FontSize="12" FontWeight="Bold" Margin="6,0,0,0"
+                                           VerticalAlignment="Center"
+                                           Foreground="{Binding Foreground, RelativeSource={RelativeSource AncestorType=ToggleButton}}"/>
+                            </StackPanel>
                         </ToggleButton>
                     </StackPanel>
                 </Border>
+                <TextBlock Text="One output at a time" FontSize="11" VerticalAlignment="Center"
+                           Foreground="{StaticResource Brush.OnSurfaceVariant}" Margin="8,0,0,0"/>
                 <!-- Go face names the world: "Start Recording" vs "Go Live".
                      (Signed-out ON-AIR Start routes to the sign-in — StartSession.) -->
                 <Button Content="{Binding PrimaryStartButtonLabel}" Style="{StaticResource YtButton}"
diff --git a/ViewModels/MainViewModel.Streaming.cs b/ViewModels/MainViewModel.Streaming.cs
index 008392e..1268453 100644
--- a/ViewModels/MainViewModel.Streaming.cs
+++ b/ViewModels/MainViewModel.Streaming.cs
@@ -41,7 +41,9 @@ public partial class MainViewModel : ViewModelBase
     // ─── IsRecording / IsLive are reality. ON-AIR needs a sign-in, and the
     // ─── pills are radio-exclusive (record-OR-live, creator ruling 2026-09-01):
     // ─── arming one clears the other.
-    private bool _recordPillOn;
+    // Local MP4 is the armed output at launch (creator ruling 2026-11-12: "pos = ON (default)").
+    // Before that both were unarmed, so the output stage opened with nothing selected.
+    private bool _recordPillOn = true;
     private bool _onAirPillOn;
     private bool _isRecording;
 
diff --git a/ViewModels/MainViewModel.TopBar.cs b/ViewModels/MainViewModel.TopBar.cs
index 340f6bc..99ba03f 100644
--- a/ViewModels/MainViewModel.TopBar.cs
+++ b/ViewModels/MainViewModel.TopBar.cs
@@ -31,6 +31,10 @@ public partial class MainViewModel
     public bool IsBuildWorld => _barWorld == BarWorld.Build;
     public bool IsOutputWorld => _barWorld == BarWorld.Output;
 
+    /// <summary>The output stage belongs to the Record / Go Live world, and only while nothing is
+    /// running — a live session cannot change its output, so its switch is not offered.</summary>
+    public bool ShowOutputStage => IsOutputWorld && IsOffline && !IsRecording;
+
     public ICommand EnterBuildWorldCommand { get; private set; } = null!;
     public ICommand EnterOutputWorldCommand { get; private set; } = null!;
 
@@ -49,5 +53,6 @@ public partial class MainViewModel
         OnPropertyChanged(nameof(IsBuildWorld));
         OnPropertyChanged(nameof(IsOutputWorld));
         EditingActive = world == BarWorld.Build;
+        OnPropertyChanged(nameof(ShowOutputStage));
     }
 }
diff --git a/docs/ai/ui-surface.md b/docs/ai/ui-surface.md
index aee2818..cc07e1b 100644
--- a/docs/ai/ui-surface.md
+++ b/docs/ai/ui-surface.md
@@ -151,8 +151,13 @@ Placement math itself is covered by `WindowPlacementTests` (pure function, no HW
   leads the centre cluster and stays present in every state; clicking the highlighted half re-enters it,
   which is how a creator gets back to the layers during a session. `WorldSegmentButton`
   (`Themes/Controls.xaml`) is a Button, not a ToggleButton — the highlight follows the view model, and a
-  click must never be what sets it. Next in the same redesign: the output switch (`Output [YouTube]
-  [Local MP4] One output at a time`, MP4 default) and an output-dependent primary action.
+  click must never be what sets it.
+- **The output stage** (`ShowOutputStage`) is the idle cluster and lives only in the Record / Go Live
+  world while nothing runs: `Output [▶ YouTube] [● Local MP4] One output at a time`, each switch carrying
+  its glyph, with **Local MP4 armed at launch** (`RecordPillOn` starts true — it did not before). The two
+  are one axis and the view model already drops one when the other arms, so exclusivity is policy, not
+  layout. A running session hides the stage (its output cannot change) and the reality line plus the
+  stop action take the cluster's place. Next in the same redesign: the output-dependent primary action.
 - **Editing during a session is a setting (creator ruling 2026-11-12).** `App.LockEditWhileLive` is off
   by default: a show does not take EDIT away, so a creator may move a layer or resize a webcam while
   live. On restores the old gun-safety — go-live flips EDIT off, stop flips it back, and only because
diff --git a/ytLive.Tests/TopBarWorldTests.cs b/ytLive.Tests/TopBarWorldTests.cs
index 691be32..ddfa31a 100644
--- a/ytLive.Tests/TopBarWorldTests.cs
+++ b/ytLive.Tests/TopBarWorldTests.cs
@@ -13,6 +13,40 @@ namespace ytLive.Tests;
 [Collection("MainViewModelLayoutPath")]
 public class TopBarWorldTests
 {
+    [Fact]
+    public void The_output_stage_belongs_to_the_output_world_and_holds_one_output_at_a_time()
+    {
+        var db = Path.Combine(Path.GetTempPath(), $"llamacasty-outputstage-{Guid.NewGuid():N}.db");
+        MainViewModel.LayoutPathOverride = db;
+        try
+        {
+            var vm = new MainViewModel();
+
+            // Nothing to arm while building scenes.
+            Assert.False(vm.ShowOutputStage);
+
+            vm.EnterOutputWorldCommand.Execute(null);
+            Assert.True(vm.IsOutputWorld);
+            Assert.True(vm.IsOffline);
+            Assert.False(vm.IsRecording);
+            Assert.True(vm.ShowOutputStage);
+
+            // Local MP4 is the default output; the pair is one axis, so arming either drops the other.
+            Assert.True(vm.RecordPillOn);
+            Assert.False(vm.OnAirPillOn);
+            vm.OnAirPillOn = true;
+            Assert.True(vm.OnAirPillOn);
+            Assert.False(vm.RecordPillOn);
+            vm.RecordPillOn = true;
+            Assert.False(vm.OnAirPillOn);
+        }
+        finally
+        {
+            MainViewModel.LayoutPathOverride = null;
+            try { File.Delete(db); } catch (IOException) { }
+        }
+    }
+
     [Fact]
     public void Build_scenes_is_the_default_world_and_is_the_only_place_editing_lives()
     {
diff --git a/ytLive.Tests/UiShellTests.cs b/ytLive.Tests/UiShellTests.cs
index 31d45de..77f3f6d 100644
--- a/ytLive.Tests/UiShellTests.cs
+++ b/ytLive.Tests/UiShellTests.cs
@@ -41,6 +41,14 @@ public class UiShellTests
         Assert.Contains("Data=\"M7,10V7a5,5 0 0,1 10,0v3h1", topBar);
         Assert.Contains("Visibility=\"{Binding IsOutputWorld, Converter={StaticResource BoolToVis}}\"", topBar);
 
+        // 2c. The output stage: two labelled switches and the exclusivity promise beside them.
+        Assert.Contains("Text=\"Output\"", topBar);
+        Assert.Contains("Text=\"YouTube\"", topBar);
+        Assert.Contains("Text=\"Local MP4\"", topBar);
+        Assert.Contains("Text=\"One output at a time\"", topBar);
+        Assert.Contains("IsChecked=\"{Binding OnAirPillOn}\"", topBar);
+        Assert.Contains("IsChecked=\"{Binding RecordPillOn}\"", topBar);
+
         // 3. Active scene = orange; live stays red.
         Assert.Contains("IsStaged}\" Value=\"True\">\n                                        <Setter Property=\"BorderBrush\" Value=\"{StaticResource Brush.Attention}\"/>", strip);