add CmdPal_SessionDuration telemetry event

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.ViewModels/Messages/ErrorOccurredMessage.cs

@@ -0,0 +1,11 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Microsoft.CmdPal.Core.ViewModels.Messages;
+
+/// <summary>
+/// Message sent when an error occurs during command execution.
+/// Used to track session error count for telemetry.
+/// </summary>
+public record ErrorOccurredMessage();

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.ViewModels/Messages/ExtensionInvokedMessage.cs

@@ -4,4 +4,8 @@
 
 namespace Microsoft.CmdPal.Core.ViewModels.Messages;
 
+/// <summary>
+/// Message sent when an extension command or page is invoked.
+/// Captures extension usage metrics for telemetry tracking.
+/// </summary>
 public record ExtensionInvokedMessage(string ExtensionId, string CommandType, bool Success, ulong ExecutionTimeMs);

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.ViewModels/Messages/NavigationDepthMessage.cs

@@ -0,0 +1,11 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Microsoft.CmdPal.Core.ViewModels.Messages;
+
+/// <summary>
+/// Message containing the current navigation depth (BackStack count) when navigating to a page.
+/// Used to track maximum navigation depth reached during a session for telemetry.
+/// </summary>
+public record NavigationDepthMessage(int Depth);

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.ViewModels/Messages/SearchQueryMessage.cs

@@ -0,0 +1,11 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Microsoft.CmdPal.Core.ViewModels.Messages;
+
+/// <summary>
+/// Message sent when a search query is executed in the Command Palette.
+/// Used to track session search activity for telemetry.
+/// </summary>
+public record SearchQueryMessage();

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.ViewModels/Messages/SessionDurationMessage.cs

@@ -0,0 +1,11 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+namespace Microsoft.CmdPal.Core.ViewModels.Messages;
+
+/// <summary>
+/// Message containing session telemetry data from Command Palette launch to dismissal.
+/// Used to aggregate metrics like duration, commands executed, pages visited, and search activity.
+/// </summary>
+public record SessionDurationMessage(ulong DurationMs, int CommandsExecuted, int PagesVisited, string DismissalReason, int SearchQueriesCount, int MaxNavigationDepth, int ErrorCount);

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.ViewModels/ShellViewModel.cs

@@ -269,7 +269,7 @@ public partial class ShellViewModel : ObservableObject,
                 var isMainPage = command == _rootPage;
                 _isNested = !isMainPage;
 
-                // Track extension page navigation
+                // Telemetry: Track extension page navigation for session metrics
                 if (host is not null)
                 {
                     string extensionId = host.GetExtensionDisplayName() ?? "builtin";
@@ -347,6 +347,7 @@ public partial class ShellViewModel : ObservableObject,
 
     private void SafeHandleInvokeCommandSynchronous(PerformCommandMessage message, IInvokableCommand invokable, AppExtensionHost? host)
     {
+        // Telemetry: Track command execution time and success
         var stopwatch = System.Diagnostics.Stopwatch.StartNew();
         var command = message.Command.Unsafe;
         string extensionId = host?.GetExtensionDisplayName() ?? "builtin";
@@ -371,12 +372,16 @@ public partial class ShellViewModel : ObservableObject,
             success = false;
             _handleInvokeTask = null;
 
+            // Telemetry: Track errors for session metrics
+            WeakReferenceMessenger.Default.Send<ErrorOccurredMessage>(new());
+
             // TODO: It would be better to do this as a page exception, rather
             // than a silent log message.
             host?.Log(ex.Message);
         }
         finally
         {
+            // Telemetry: Send extension invocation metrics (always sent, even on failure)
             stopwatch.Stop();
             WeakReferenceMessenger.Default.Send<ExtensionInvokedMessage>(
                 new(extensionId, commandType, success, (ulong)stopwatch.ElapsedMilliseconds));

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/SearchBar.xaml.cs

@@ -329,6 +329,12 @@ public sealed partial class SearchBar : UserControl,
         if (CurrentPageViewModel is not null)
         {
             CurrentPageViewModel.SearchTextBox = FilterBox.Text;
+
+            // Telemetry: Track search query count for session metrics (only non-empty queries)
+            if (!string.IsNullOrWhiteSpace(FilterBox.Text))
+            {
+                WeakReferenceMessenger.Default.Send<SearchQueryMessage>(new());
+            }
         }
     }
 

src/modules/cmdpal/Microsoft.CmdPal.UI/Events/CmdPalSessionDuration.cs

@@ -0,0 +1,68 @@
+// Copyright (c) Microsoft Corporation
+// The Microsoft Corporation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using System.Diagnostics.CodeAnalysis;
+using System.Diagnostics.Tracing;
+using Microsoft.PowerToys.Telemetry;
+using Microsoft.PowerToys.Telemetry.Events;
+
+namespace Microsoft.CmdPal.UI.Events;
+
+/// <summary>
+/// Tracks Command Palette session duration from launch to close.
+/// Purpose: Understand user engagement patterns - quick actions vs. browsing behavior.
+/// </summary>
+[EventData]
+[DynamicallyAccessedMembers(DynamicallyAccessedMemberTypes.PublicProperties)]
+public class CmdPalSessionDuration : EventBase, IEvent
+{
+    /// <summary>
+    /// Gets or sets the session duration in milliseconds.
+    /// </summary>
+    public ulong DurationMs { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of commands executed during the session.
+    /// </summary>
+    public int CommandsExecuted { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of pages visited during the session.
+    /// </summary>
+    public int PagesVisited { get; set; }
+
+    /// <summary>
+    /// Gets or sets the reason for dismissal (Escape, LostFocus, Command, etc.).
+    /// </summary>
+    public string DismissalReason { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of search queries executed during the session.
+    /// </summary>
+    public int SearchQueriesCount { get; set; }
+
+    /// <summary>
+    /// Gets or sets the maximum navigation depth reached during the session.
+    /// </summary>
+    public int MaxNavigationDepth { get; set; }
+
+    /// <summary>
+    /// Gets or sets the number of errors encountered during the session.
+    /// </summary>
+    public int ErrorCount { get; set; }
+
+    public CmdPalSessionDuration(ulong durationMs, int commandsExecuted, int pagesVisited, string dismissalReason, int searchQueriesCount, int maxNavigationDepth, int errorCount)
+    {
+        EventName = "CmdPal_SessionDuration";
+        DurationMs = durationMs;
+        CommandsExecuted = commandsExecuted;
+        PagesVisited = pagesVisited;
+        DismissalReason = dismissalReason;
+        SearchQueriesCount = searchQueriesCount;
+        MaxNavigationDepth = maxNavigationDepth;
+        ErrorCount = errorCount;
+    }
+
+    public PartA_PrivTags PartA_PrivTags => PartA_PrivTags.ProductAndServiceUsage;
+}

src/modules/cmdpal/Microsoft.CmdPal.UI/Helpers/TelemetryForwarder.cs

@@ -23,13 +23,15 @@ internal sealed class TelemetryForwarder :
     ITelemetryService,
     IRecipient<BeginInvokeMessage>,
     IRecipient<CmdPalInvokeResultMessage>,
-    IRecipient<ExtensionInvokedMessage>
+    IRecipient<ExtensionInvokedMessage>,
+    IRecipient<SessionDurationMessage>
 {
     public TelemetryForwarder()
     {
         WeakReferenceMessenger.Default.Register<BeginInvokeMessage>(this);
         WeakReferenceMessenger.Default.Register<CmdPalInvokeResultMessage>(this);
         WeakReferenceMessenger.Default.Register<ExtensionInvokedMessage>(this);
+        WeakReferenceMessenger.Default.Register<SessionDurationMessage>(this);
     }
 
     public void Receive(CmdPalInvokeResultMessage message)
@@ -51,6 +53,18 @@ internal sealed class TelemetryForwarder :
             message.ExecutionTimeMs));
     }
 
+    public void Receive(SessionDurationMessage message)
+    {
+        PowerToysTelemetry.Log.WriteEvent(new CmdPalSessionDuration(
+            message.DurationMs,
+            message.CommandsExecuted,
+            message.PagesVisited,
+            message.DismissalReason,
+            message.SearchQueriesCount,
+            message.MaxNavigationDepth,
+            message.ErrorCount));
+    }
+
     public void LogRunQuery(string query, int resultCount, ulong durationMs)
     {
         PowerToysTelemetry.Log.WriteEvent(new CmdPalRunQuery(query, resultCount, durationMs));

src/modules/cmdpal/Microsoft.CmdPal.UI/MainWindow.xaml.cs

@@ -49,6 +49,11 @@ public sealed partial class MainWindow : WindowEx,
     IRecipient<ShowWindowMessage>,
     IRecipient<HideWindowMessage>,
     IRecipient<QuitMessage>,
+    IRecipient<ExtensionInvokedMessage>,
+    IRecipient<NavigateToPageMessage>,
+    IRecipient<NavigationDepthMessage>,
+    IRecipient<SearchQueryMessage>,
+    IRecipient<ErrorOccurredMessage>,
     IDisposable
 {
     private const int DefaultWidth = 800;
@@ -66,6 +71,14 @@ public sealed partial class MainWindow : WindowEx,
     private readonly HiddenOwnerWindowBehavior _hiddenOwnerBehavior = new();
     private bool _ignoreHotKeyWhenFullScreen = true;
 
+    // Session tracking for telemetry
+    private Stopwatch? _sessionStopwatch;
+    private int _sessionCommandsExecuted;
+    private int _sessionPagesVisited;
+    private int _sessionSearchQueriesCount;
+    private int _sessionMaxNavigationDepth;
+    private int _sessionErrorCount;
+
     private DesktopAcrylicController? _acrylicController;
     private SystemBackdropConfiguration? _configurationSource;
 
@@ -100,6 +113,11 @@ public sealed partial class MainWindow : WindowEx,
         WeakReferenceMessenger.Default.Register<QuitMessage>(this);
         WeakReferenceMessenger.Default.Register<ShowWindowMessage>(this);
         WeakReferenceMessenger.Default.Register<HideWindowMessage>(this);
+        WeakReferenceMessenger.Default.Register<ExtensionInvokedMessage>(this);
+        WeakReferenceMessenger.Default.Register<NavigateToPageMessage>(this);
+        WeakReferenceMessenger.Default.Register<NavigationDepthMessage>(this);
+        WeakReferenceMessenger.Default.Register<SearchQueryMessage>(this);
+        WeakReferenceMessenger.Default.Register<ErrorOccurredMessage>(this);
 
         // Hide our titlebar.
         // We need to both ExtendsContentIntoTitleBar, then set the height to Collapsed
@@ -484,6 +502,11 @@ public sealed partial class MainWindow : WindowEx,
     {
         var settings = App.Current.Services.GetService<SettingsModel>()!;
 
+        // Start session tracking
+        _sessionStopwatch = Stopwatch.StartNew();
+        _sessionCommandsExecuted = 0;
+        _sessionPagesVisited = 0;
+
         ShowHwnd(message.Hwnd, settings.SummonOn);
     }
 
@@ -492,6 +515,7 @@ public sealed partial class MainWindow : WindowEx,
         // This might come in off the UI thread. Make sure to hop back.
         DispatcherQueue.TryEnqueue(() =>
         {
+            EndSession("Hide");
             HideWindow();
         });
     }
@@ -506,10 +530,64 @@ public sealed partial class MainWindow : WindowEx,
         // This might come in off the UI thread. Make sure to hop back.
         DispatcherQueue.TryEnqueue(() =>
         {
+            EndSession("Dismiss");
             HideWindow();
         });
     }
 
+    // Session telemetry: Track metrics during the Command Palette session
+    // These receivers increment counters that are sent when EndSession is called
+
+    public void Receive(ExtensionInvokedMessage message)
+    {
+        _sessionCommandsExecuted++;
+    }
+
+    public void Receive(NavigateToPageMessage message)
+    {
+        _sessionPagesVisited++;
+    }
+
+    public void Receive(NavigationDepthMessage message)
+    {
+        if (message.Depth > _sessionMaxNavigationDepth)
+        {
+            _sessionMaxNavigationDepth = message.Depth;
+        }
+    }
+
+    public void Receive(SearchQueryMessage message)
+    {
+        _sessionSearchQueriesCount++;
+    }
+
+    public void Receive(ErrorOccurredMessage message)
+    {
+        _sessionErrorCount++;
+    }
+
+    /// <summary>
+    /// Ends the current telemetry session and emits the CmdPal_SessionDuration event.
+    /// Aggregates all session metrics collected since ShowWindow and sends them to telemetry.
+    /// </summary>
+    /// <param name="dismissalReason">The reason the session ended (e.g., Dismiss, Hide, LostFocus).</param>
+    private void EndSession(string dismissalReason)
+    {
+        if (_sessionStopwatch is not null)
+        {
+            _sessionStopwatch.Stop();
+            WeakReferenceMessenger.Default.Send<SessionDurationMessage>(new(
+                (ulong)_sessionStopwatch.ElapsedMilliseconds,
+                _sessionCommandsExecuted,
+                _sessionPagesVisited,
+                dismissalReason,
+                _sessionSearchQueriesCount,
+                _sessionMaxNavigationDepth,
+                _sessionErrorCount));
+            _sessionStopwatch = null;
+        }
+    }
+
     private void HideWindow()
     {
         // Cloak our HWND to avoid all animations.
@@ -681,6 +759,7 @@ public sealed partial class MainWindow : WindowEx,
             }
 
             // This will DWM cloak our window:
+            EndSession("LostFocus");
             HideWindow();
 
             PowerToysTelemetry.Log.WriteEvent(new CmdPalDismissedOnLostFocus());

src/modules/cmdpal/Microsoft.CmdPal.UI/Pages/ShellPage.xaml.cs

@@ -161,6 +161,9 @@ public sealed partial class ShellPage : Microsoft.UI.Xaml.Controls.Page,
 
             PowerToysTelemetry.Log.WriteEvent(new OpenPage(RootFrame.BackStackDepth, message.Page.Id));
 
+            // Telemetry: Send navigation depth for session max depth tracking
+            WeakReferenceMessenger.Default.Send(new NavigationDepthMessage(RootFrame.BackStackDepth));
+
             if (!ViewModel.IsNested)
             {
                 // todo BODGY