check in custon action

<!-- Enter a brief description/summary of your PR here. What does it
fix/what does it change/how was it tested (even manually, if necessary)?
-->
## Summary of the Pull Request
Transparency support (best-effort)
> Not every window can be made transparent. Transparency is applied on a
best-effort basis and depends on how the target app/window is built and
rendered.

## When it may not work
* Windows with special rendering pipelines (e.g., certain
hardware-accelerated / compositor-managed surfaces).
* Some tool/popup/owned windows where the foreground window isn’t the
actual surface being drawn.

## How it works (high-level)
* Resolve the best target window (preferring the top-level/root window
over transient children).
* Apply Windows’ standard layered-window alpha mechanism (per-window
opacity) to adjust transparency.
* When unpinned, Restore the original opacity/state when possible.

If transparency doesn’t change, it means the window doesn’t support this
mechanism in its current configuration.
<!-- Please review the items on the PR checklist before submitting-->
## PR Checklist

- [X] Closes: 
#43278 
#42929
#28773

<!-- - [ ] Closes: #yyy (add separate lines for additional resolved
issues) -->
- [ ] **Communication:** I've discussed this with core contributors
already. If the work hasn't been agreed, this work might be rejected
- [ ] **Tests:** Added/updated and all pass
- [ ] **Localization:** All end-user-facing strings can be localized
- [ ] **Dev docs:** Added/updated
- [ ] **New binaries:** Added on the required places
- [ ] [JSON for
signing](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ESRPSigning_core.json)
for new binaries
- [ ] [WXS for
installer](https://github.com/microsoft/PowerToys/blob/main/installer/PowerToysSetup/Product.wxs)
for new binaries and localization folder
- [ ] [YML for CI
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/ci/templates/build-powertoys-steps.yml)
for new test projects
- [ ] [YML for signed
pipeline](https://github.com/microsoft/PowerToys/blob/main/.pipelines/release.yml)
- [ ] **Documentation updated:** If checked, please file a pull request
on [our docs
repo](https://github.com/MicrosoftDocs/windows-uwp/tree/docs/hub/powertoys)
and link it here: #xxx

<!-- Provide a more detailed description of the PR, other things fixed,
or any additional comments/features here -->
## Detailed Description of the Pull Request / Additional comments

<!-- Describe how you validated the behavior. Add automated tests
wherever possible, but list manual validation steps taken as well -->
## Validation Steps Performed


https://github.com/user-attachments/assets/c97a87f2-3126-4e19-990f-8c684dbeb631

<img width="1119" height="426" alt="image"
src="https://github.com/user-attachments/assets/547671ee-81d3-4c94-8199-bf0c4b1b7760"
/>

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

.github/actions/spell-check/candidate.patterns

@@ -565,7 +565,7 @@ perl(?:\s+-[a-zA-Z]\w*)+
 regexp?\.MustCompile\((?:`[^`]*`|".*"|'.*')\)
 
 # regex choice
-\(\?:[^)]+\|[^)]+\)
+# \(\?:[^)]+\|[^)]+\)
 
 # proto
 ^\s*(\w+)\s\g{-1} =

.github/actions/spell-check/excludes.txt

@@ -104,8 +104,12 @@
 ^src/common/ManagedCommon/ColorFormatHelper\.cs$
 ^src/common/notifications/BackgroundActivatorDLL/cpp\.hint$
 ^src/common/sysinternals/Eula/
+^src/modules/cmdpal/Tests/Microsoft\.CommandPalette\.Extensions\.Toolkit\.UnitTests/FuzzyMatcherComparisonTests.cs$
+^src/modules/cmdpal/Tests/Microsoft\.CommandPalette\.Extensions\.Toolkit\.UnitTests/FuzzyMatcherDiacriticsTests.cs$
 ^src/modules/cmdpal/doc/initial-sdk-spec/list-elements-mock-002\.pdn$
 ^src/modules/cmdpal/ext/SamplePagesExtension/Pages/SampleMarkdownImagesPage\.cs$
+^src/modules/cmdpal/Microsoft\.CmdPal\.UI/Settings/InternalPage\.SampleData\.cs$
+^src/modules/cmdpal/Tests/Microsoft\.CmdPal\.Core\.Common\.UnitTests/.*\.TestData\.cs$
 ^src/modules/colorPicker/ColorPickerUI/Shaders/GridShader\.cso$
 ^src/modules/launcher/Plugins/Microsoft\.PowerToys\.Run\.Plugin\.TimeDate/Properties/
 ^src/modules/MouseUtils/MouseJumpUI/MainForm\.resx$

.github/actions/spell-check/expect.txt

@@ -597,6 +597,7 @@ frm
 FROMTOUCH
 fsanitize
 fsmgmt
+ftps
 fuzzingtesting
 fxf
 FZE
@@ -1329,7 +1330,7 @@ phwnd
 pici
 pidl
 PIDLIST
-PII
+pii
 pinfo
 pinvoke
 pipename
@@ -1531,6 +1532,7 @@ riid
 RKey
 RNumber
 rollups
+ROOTOWNER
 rop
 ROUNDSMALL
 ROWSETEXT
@@ -1715,6 +1717,7 @@ srw
 srwlock
 sse
 ssf
+Ssn
 sszzz
 STACKFRAME
 stackoverflow
@@ -1824,6 +1827,7 @@ TEXTBOXNEWLINE
 textextractor
 TEXTINCLUDE
 tfopen
+tgamma
 tgz
 THEMECHANGED
 themeresources

PowerToys.slnx

@@ -300,6 +300,10 @@
     </Project>
   </Folder>
   <Folder Name="/modules/CommandPalette/Tests/">
+    <Project Path="src/modules/cmdpal/Tests/Microsoft.CmdPal.Core.Common.UnitTests/Microsoft.CmdPal.Core.Common.UnitTests.csproj">
+      <Platform Solution="*|ARM64" Project="ARM64" />
+      <Platform Solution="*|x64" Project="x64" />
+    </Project>
     <Project Path="src/modules/cmdpal/Tests/Microsoft.CmdPal.Ext.Apps.UnitTests/Microsoft.CmdPal.Ext.Apps.UnitTests.csproj">
       <Platform Solution="*|ARM64" Project="ARM64" />
       <Platform Solution="*|x64" Project="x64" />
@@ -356,6 +360,10 @@
       <Platform Solution="*|ARM64" Project="ARM64" />
       <Platform Solution="*|x64" Project="x64" />
     </Project>
+    <Project Path="src/modules/cmdpal/Tests/Microsoft.CommandPalette.Extensions.Toolkit.UnitTests/Microsoft.CommandPalette.Extensions.Toolkit.UnitTests.csproj" Id="2eca18b7-33b7-4829-88f1-439b20fd60f6">
+      <Platform Solution="*|ARM64" Project="ARM64" />
+      <Platform Solution="*|x64" Project="x64" />
+    </Project>
   </Folder>
   <Folder Name="/modules/CommandPalette/UI/">
     <Project Path="src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Microsoft.CmdPal.UI.ViewModels.csproj">

installer/PowerToysSetupCustomActionsVNext/CustomAction.cpp

@@ -610,6 +610,13 @@ UINT __stdcall InstallPackageIdentityMSIXCA(MSIHANDLE hInstall)
     hr = WcaInitialize(hInstall, "InstallPackageIdentityMSIXCA");
     ExitOnFailure(hr, "Failed to initialize");
 
+    // Double-check: Only install on Windows 11 or greater
+    if (!package::IsWin11OrGreater())
+    {
+        Logger::info(L"Skipping PackageIdentity MSIX installation - not Windows 11 or greater");
+        goto LExit;
+    }
+
     hr = WcaGetProperty(L"CustomActionData", &customActionData);
     ExitOnFailure(hr, "Failed to get CustomActionData property");
     

installer/PowerToysSetupVNext/Product.wxs

@@ -124,7 +124,7 @@
       <Custom Action="SetBundleInstallLocation" After="InstallFiles" Condition="NOT Installed OR WIX_UPGRADE_DETECTED" />
       <Custom Action="ApplyModulesRegistryChangeSets" After="InstallFiles" Condition="NOT Installed" />
       <Custom Action="InstallCmdPalPackage" After="InstallFiles" Condition="NOT Installed" />
-      <Custom Action="InstallPackageIdentityMSIX" After="InstallFiles" Condition="NOT Installed AND WINDOWSBUILDNUMBER &gt;= 22000" />
+      <Custom Action="InstallPackageIdentityMSIX" After="InstallFiles" Condition="(NOT Installed) AND (WINDOWSBUILDNUMBER &gt;= 22000)" />
       <Custom Action="override Wix4CloseApplications_$(sys.BUILDARCHSHORT)" Before="RemoveFiles" />
       <Custom Action="RemovePowerToysSchTasks" After="RemoveFiles" />
       <!-- TODO: Use to activate embedded MSIX -->

src/common/CalculatorEngineCommon/ExprtkEvaluator.cpp

@@ -3,9 +3,27 @@
 #include <iomanip>
 #include <iostream>
 #include <sstream>
+#include <cmath>
+#include <limits>
 
 namespace ExprtkCalculator::internal
 {
+    static double factorial(const double n)
+    {
+        // Only allow non-negative integers
+        if (n < 0.0 || std::floor(n) != n)
+        {
+            return std::numeric_limits<double>::quiet_NaN();
+        }
+        return std::tgamma(n + 1.0);
+    }
+
+    static double sign(const double n)
+    {
+        if (n > 0.0) return 1.0;
+        if (n < 0.0) return -1.0;
+        return 0.0;
+    }
 
     std::wstring ToWStringFullPrecision(double value)
     {
@@ -25,6 +43,9 @@ namespace ExprtkCalculator::internal
             symbol_table.add_constant(name, value);
         }
 
+        symbol_table.add_function("factorial", factorial);
+        symbol_table.add_function("sign", sign);
+
         exprtk::expression<double> expression;
         expression.register_symbol_table(symbol_table);
 

src/common/interop/shared_constants.h

@@ -72,6 +72,10 @@ namespace CommonSharedConstants
 
     const wchar_t ALWAYS_ON_TOP_TERMINATE_EVENT[] = L"Local\\AlwaysOnTopTerminateEvent-cfdf1eae-791f-4953-8021-2f18f3837eae";
 
+    const wchar_t ALWAYS_ON_TOP_INCREASE_OPACITY_EVENT[] = L"Local\\AlwaysOnTopIncreaseOpacityEvent-a1b2c3d4-e5f6-7890-abcd-ef1234567890";
+
+    const wchar_t ALWAYS_ON_TOP_DECREASE_OPACITY_EVENT[] = L"Local\\AlwaysOnTopDecreaseOpacityEvent-b2c3d4e5-f6a7-8901-bcde-f12345678901";
+
     // Path to the event used by PowerAccent
     const wchar_t POWERACCENT_EXIT_EVENT[] = L"Local\\PowerToysPowerAccentExitEvent-53e93389-d19a-4fbb-9b36-1981c8965e17";
 

src/modules/alwaysontop/AlwaysOnTop/AlwaysOnTop.cpp

@@ -153,9 +153,21 @@ LRESULT AlwaysOnTop::WndProc(HWND window, UINT message, WPARAM wparam, LPARAM lp
 {
     if (message == WM_HOTKEY)
     {
+        int hotkeyId = static_cast<int>(wparam);
         if (HWND fw{ GetForegroundWindow() })
         {
-            ProcessCommand(fw);
+            if (hotkeyId == static_cast<int>(HotkeyId::Pin))
+            {
+                ProcessCommand(fw);
+            }
+            else if (hotkeyId == static_cast<int>(HotkeyId::IncreaseOpacity))
+            {
+                StepWindowTransparency(fw, Settings::transparencyStep);
+            }
+            else if (hotkeyId == static_cast<int>(HotkeyId::DecreaseOpacity))
+            {
+                StepWindowTransparency(fw, -Settings::transparencyStep);
+            }
         }
     }
     else if (message == WM_PRIV_SETTINGS_CHANGED)
@@ -191,6 +203,10 @@ void AlwaysOnTop::ProcessCommand(HWND window)
                 m_topmostWindows.erase(iter);
             }
 
+            // Restore transparency when unpinning
+            RestoreWindowAlpha(window);
+            m_windowOriginalLayeredState.erase(window);
+
             Trace::AlwaysOnTop::UnpinWindow();
         }
     }
@@ -200,6 +216,7 @@ void AlwaysOnTop::ProcessCommand(HWND window)
         {
             soundType = Sound::Type::On;
             AssignBorder(window);
+            
             Trace::AlwaysOnTop::PinWindow();
         }
     }
@@ -269,11 +286,22 @@ void AlwaysOnTop::RegisterHotkey() const
 {
     if (m_useCentralizedLLKH)
     {
+        // All hotkeys are handled by centralized LLKH
         return;
     }
 
+    // Register hotkeys only when not using centralized LLKH
     UnregisterHotKey(m_window, static_cast<int>(HotkeyId::Pin));
+    UnregisterHotKey(m_window, static_cast<int>(HotkeyId::IncreaseOpacity));
+    UnregisterHotKey(m_window, static_cast<int>(HotkeyId::DecreaseOpacity));
+
+    // Register pin hotkey
     RegisterHotKey(m_window, static_cast<int>(HotkeyId::Pin), AlwaysOnTopSettings::settings().hotkey.get_modifiers(), AlwaysOnTopSettings::settings().hotkey.get_code());
+
+    // Register transparency hotkeys using the same modifiers as the pin hotkey
+    UINT modifiers = AlwaysOnTopSettings::settings().hotkey.get_modifiers();
+    RegisterHotKey(m_window, static_cast<int>(HotkeyId::IncreaseOpacity), modifiers, VK_OEM_PLUS);
+    RegisterHotKey(m_window, static_cast<int>(HotkeyId::DecreaseOpacity), modifiers, VK_OEM_MINUS);
 }
 
 void AlwaysOnTop::RegisterLLKH()
@@ -285,6 +313,8 @@ void AlwaysOnTop::RegisterLLKH()
 	
     m_hPinEvent = CreateEventW(nullptr, false, false, CommonSharedConstants::ALWAYS_ON_TOP_PIN_EVENT);
     m_hTerminateEvent = CreateEventW(nullptr, false, false, CommonSharedConstants::ALWAYS_ON_TOP_TERMINATE_EVENT);
+    m_hIncreaseOpacityEvent = CreateEventW(nullptr, false, false, CommonSharedConstants::ALWAYS_ON_TOP_INCREASE_OPACITY_EVENT);
+    m_hDecreaseOpacityEvent = CreateEventW(nullptr, false, false, CommonSharedConstants::ALWAYS_ON_TOP_DECREASE_OPACITY_EVENT);
 
     if (!m_hPinEvent)
     {
@@ -298,30 +328,54 @@ void AlwaysOnTop::RegisterLLKH()
         return;
     }
 
-    HANDLE handles[2] = { m_hPinEvent,
-                          m_hTerminateEvent };
+    if (!m_hIncreaseOpacityEvent)
+    {
+        Logger::warn(L"Failed to create increaseOpacityEvent. {}", get_last_error_or_default(GetLastError()));
+    }
+
+    if (!m_hDecreaseOpacityEvent)
+    {
+        Logger::warn(L"Failed to create decreaseOpacityEvent. {}", get_last_error_or_default(GetLastError()));
+    }
+
+    HANDLE handles[4] = { m_hPinEvent,
+                          m_hTerminateEvent,
+                          m_hIncreaseOpacityEvent,
+                          m_hDecreaseOpacityEvent };
 
     m_thread = std::thread([this, handles]() {
         MSG msg;
         while (m_running)
         {
-            DWORD dwEvt = MsgWaitForMultipleObjects(2, handles, false, INFINITE, QS_ALLINPUT);
+            DWORD dwEvt = MsgWaitForMultipleObjects(4, handles, false, INFINITE, QS_ALLINPUT);
             if (!m_running)
             {
                 break;
             }
             switch (dwEvt)
             {
-            case WAIT_OBJECT_0:
+            case WAIT_OBJECT_0: // Pin event
                 if (HWND fw{ GetForegroundWindow() })
                 {
                     ProcessCommand(fw);
                 }
                 break;
-            case WAIT_OBJECT_0 + 1:
+            case WAIT_OBJECT_0 + 1: // Terminate event
                 PostThreadMessage(m_mainThreadId, WM_QUIT, 0, 0);
                 break;
-            case WAIT_OBJECT_0 + 2:
+            case WAIT_OBJECT_0 + 2: // Increase opacity event
+                if (HWND fw{ GetForegroundWindow() })
+                {
+                    StepWindowTransparency(fw, Settings::transparencyStep);
+                }
+                break;
+            case WAIT_OBJECT_0 + 3: // Decrease opacity event
+                if (HWND fw{ GetForegroundWindow() })
+                {
+                    StepWindowTransparency(fw, -Settings::transparencyStep);
+                }
+                break;
+            case WAIT_OBJECT_0 + 4: // Message queue
                 if (PeekMessageW(&msg, nullptr, 0, 0, PM_REMOVE))
                 {
                     TranslateMessage(&msg);
@@ -370,9 +424,12 @@ void AlwaysOnTop::UnpinAll()
         {
             Logger::error(L"Unpinning topmost window failed");
         }
+        // Restore transparency when unpinning all
+        RestoreWindowAlpha(topWindow);
     }
 
     m_topmostWindows.clear();
+    m_windowOriginalLayeredState.clear();
 }
 
 void AlwaysOnTop::CleanUp()
@@ -456,6 +513,7 @@ void AlwaysOnTop::HandleWinHookEvent(WinHookEvent* data) noexcept
     for (const auto window : toErase)
     {
         m_topmostWindows.erase(window);
+        m_windowOriginalLayeredState.erase(window);
     }
 
     switch (data->event)
@@ -556,4 +614,166 @@ void AlwaysOnTop::RefreshBorders()
             }
         }
     }
+}
+
+HWND AlwaysOnTop::ResolveTransparencyTargetWindow(HWND window)
+{
+    if (!window || !IsWindow(window))
+    {
+        return nullptr;
+    }
+
+    // Only allow transparency changes on pinned windows
+    if (!IsPinned(window))
+    {
+        return nullptr;
+    }
+
+    return window;
+}
+
+
+void AlwaysOnTop::StepWindowTransparency(HWND window, int delta)
+{
+    HWND targetWindow = ResolveTransparencyTargetWindow(window);
+    if (!targetWindow)
+    {
+        return;
+    }
+
+    int currentTransparency = Settings::maxTransparencyPercentage;
+    LONG exStyle = GetWindowLong(targetWindow, GWL_EXSTYLE);
+    if (exStyle & WS_EX_LAYERED)
+    {
+        BYTE alpha = 255;
+        if (GetLayeredWindowAttributes(targetWindow, nullptr, &alpha, nullptr))
+        {
+            currentTransparency = (alpha * 100) / 255;
+        }
+    }
+
+    int newTransparency = (std::max)(Settings::minTransparencyPercentage, 
+                                     (std::min)(Settings::maxTransparencyPercentage, currentTransparency + delta));
+
+    if (newTransparency != currentTransparency)
+    {
+        ApplyWindowAlpha(targetWindow, newTransparency);
+
+        if (AlwaysOnTopSettings::settings().enableSound)
+        {
+            m_sound.Play(delta > 0 ? Sound::Type::IncreaseOpacity : Sound::Type::DecreaseOpacity);
+        }
+
+        Logger::debug(L"Transparency adjusted to {}%", newTransparency);
+    }
+}
+
+void AlwaysOnTop::ApplyWindowAlpha(HWND window, int percentage)
+{
+    if (!window || !IsWindow(window))
+    {
+        return;
+    }
+    
+    percentage = (std::max)(Settings::minTransparencyPercentage, 
+                            (std::min)(Settings::maxTransparencyPercentage, percentage));
+
+    LONG exStyle = GetWindowLong(window, GWL_EXSTYLE);
+    bool isCurrentlyLayered = (exStyle & WS_EX_LAYERED) != 0;
+
+    // Cache original state on first transparency application
+    if (m_windowOriginalLayeredState.find(window) == m_windowOriginalLayeredState.end())
+    {
+        WindowLayeredState state;
+        state.hadLayeredStyle = isCurrentlyLayered;
+        
+        if (isCurrentlyLayered)
+        {
+            BYTE alpha = 255;
+            COLORREF colorKey = 0;
+            DWORD flags = 0;
+            if (GetLayeredWindowAttributes(window, &colorKey, &alpha, &flags))
+            {
+                state.originalAlpha = alpha;
+                state.usedColorKey = (flags & LWA_COLORKEY) != 0;
+                state.colorKey = colorKey;
+            }
+            else
+            {
+                Logger::warn(L"GetLayeredWindowAttributes failed for layered window, skipping");
+                return;
+            }
+        }
+        m_windowOriginalLayeredState[window] = state;
+    }
+
+    // Clear WS_EX_LAYERED first to ensure SetLayeredWindowAttributes works
+    if (isCurrentlyLayered)
+    {
+        SetWindowLong(window, GWL_EXSTYLE, exStyle & ~WS_EX_LAYERED);
+        SetWindowPos(window, nullptr, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);
+        exStyle = GetWindowLong(window, GWL_EXSTYLE);
+    }
+
+    BYTE alphaValue = static_cast<BYTE>((255 * percentage) / 100);
+    SetWindowLong(window, GWL_EXSTYLE, exStyle | WS_EX_LAYERED);
+    SetLayeredWindowAttributes(window, 0, alphaValue, LWA_ALPHA);
+}
+
+void AlwaysOnTop::RestoreWindowAlpha(HWND window)
+{
+    if (!window || !IsWindow(window))
+    {
+        return;
+    }
+
+    LONG exStyle = GetWindowLong(window, GWL_EXSTYLE);
+    auto it = m_windowOriginalLayeredState.find(window);
+    
+    if (it != m_windowOriginalLayeredState.end())
+    {
+        const auto& originalState = it->second;
+        
+        if (originalState.hadLayeredStyle)
+        {
+            // Window originally had WS_EX_LAYERED - restore original attributes
+            // Clear and re-add to ensure clean state
+            if (exStyle & WS_EX_LAYERED)
+            {
+                SetWindowLong(window, GWL_EXSTYLE, exStyle & ~WS_EX_LAYERED);
+                exStyle = GetWindowLong(window, GWL_EXSTYLE);
+            }
+            SetWindowLong(window, GWL_EXSTYLE, exStyle | WS_EX_LAYERED);
+            
+            // Restore original alpha and/or color key
+            DWORD flags = LWA_ALPHA;
+            if (originalState.usedColorKey)
+            {
+                flags |= LWA_COLORKEY;
+            }
+            SetLayeredWindowAttributes(window, originalState.colorKey, originalState.originalAlpha, flags);
+            SetWindowPos(window, nullptr, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);
+        }
+        else
+        {
+            // Window originally didn't have WS_EX_LAYERED - remove it completely
+            if (exStyle & WS_EX_LAYERED)
+            {
+                SetLayeredWindowAttributes(window, 0, 255, LWA_ALPHA);
+                SetWindowLong(window, GWL_EXSTYLE, exStyle & ~WS_EX_LAYERED);
+                SetWindowPos(window, nullptr, 0, 0, 0, 0, SWP_NOMOVE | SWP_NOSIZE | SWP_NOZORDER | SWP_FRAMECHANGED);
+            }
+        }
+        
+        m_windowOriginalLayeredState.erase(it);
+    }
+    else
+    {
+        // Fallback: no cached state, just remove layered style
+        if (exStyle & WS_EX_LAYERED)
+        {
+            SetLayeredWindowAttributes(window, 0, 255, LWA_ALPHA);
+            SetWindowLong(window, GWL_EXSTYLE, exStyle & ~WS_EX_LAYERED);
+        }
+    }
 }

src/modules/alwaysontop/AlwaysOnTop/AlwaysOnTop.h

@@ -10,6 +10,7 @@
 
 #include <common/hooks/WinHookEvent.h>
 #include <common/notifications/NotificationUtil.h>
+#include <common/utils/window.h>
 
 class AlwaysOnTop : public SettingsObserver
 {
@@ -38,6 +39,8 @@ private:
     enum class HotkeyId : int
     {
         Pin = 1,
+        IncreaseOpacity = 2,
+        DecreaseOpacity = 3,
     };
 
     static inline AlwaysOnTop* s_instance = nullptr;
@@ -48,8 +51,20 @@ private:
     HWND m_window{ nullptr };
     HINSTANCE m_hinstance;
     std::map<HWND, std::unique_ptr<WindowBorder>> m_topmostWindows{};
+    
+    // Store original window layered state for proper restoration
+    struct WindowLayeredState {
+        bool hadLayeredStyle = false;
+        BYTE originalAlpha = 255;
+        bool usedColorKey = false;
+        COLORREF colorKey = 0;
+    };
+    std::map<HWND, WindowLayeredState> m_windowOriginalLayeredState{};
+    
     HANDLE m_hPinEvent;
     HANDLE m_hTerminateEvent;
+    HANDLE m_hIncreaseOpacityEvent;
+    HANDLE m_hDecreaseOpacityEvent;
     DWORD m_mainThreadId;
     std::thread m_thread;
     const bool m_useCentralizedLLKH;
@@ -78,6 +93,12 @@ private:
     bool AssignBorder(HWND window);
     void RefreshBorders();
 
+    // Transparency methods
+    HWND ResolveTransparencyTargetWindow(HWND window);
+    void StepWindowTransparency(HWND window, int delta);
+    void ApplyWindowAlpha(HWND window, int percentage);
+    void RestoreWindowAlpha(HWND window);
+
     virtual void SettingsUpdate(SettingId type) override;
 
     static void CALLBACK WinHookProc(HWINEVENTHOOK winEventHook,

src/modules/alwaysontop/AlwaysOnTop/Settings.h

@@ -15,6 +15,9 @@ class SettingsObserver;
 struct Settings
 {
     PowerToysSettings::HotkeyObject hotkey = PowerToysSettings::HotkeyObject::from_settings(true, true, false, false, 84); // win + ctrl + T
+    static constexpr int minTransparencyPercentage = 20; // minimum transparency (can't go below 20%)
+    static constexpr int maxTransparencyPercentage = 100; // maximum (fully opaque)
+    static constexpr int transparencyStep = 10; // step size for +/- adjustment
     bool enableFrame = true;
     bool enableSound = true;
     bool roundCornersEnabled = true;

src/modules/alwaysontop/AlwaysOnTop/Sound.h

@@ -2,7 +2,6 @@
 
 #include "pch.h"
 
-#include <atomic>
 #include <mmsystem.h> // sound
 
 class Sound
@@ -12,12 +11,10 @@ public:
     {
         On,
         Off,
+        IncreaseOpacity,
+        DecreaseOpacity,
     };
     
-    Sound()
-        : isPlaying(false)
-    {}
-
     void Play(Type type)
     {
         BOOL success = false;
@@ -29,6 +26,12 @@ public:
         case Type::Off:
             success = PlaySound(TEXT("Media\\Speech Sleep.wav"), NULL, SND_FILENAME | SND_ASYNC);
             break;
+        case Type::IncreaseOpacity:
+            success = PlaySound(TEXT("Media\\Windows Hardware Insert.wav"), NULL, SND_FILENAME | SND_ASYNC);
+            break;
+        case Type::DecreaseOpacity:
+            success = PlaySound(TEXT("Media\\Windows Hardware Remove.wav"), NULL, SND_FILENAME | SND_ASYNC);
+            break;
         default:
             break;
         }
@@ -38,7 +41,4 @@ public:
             Logger::error(L"Sound playing error");
         }
     }
-
-private:
-    std::atomic<bool> isPlaying;
 };

src/modules/alwaysontop/AlwaysOnTopModuleInterface/dllmain.cpp

@@ -105,17 +105,28 @@ public:
         }
     }
 
-    virtual bool on_hotkey(size_t /*hotkeyId*/) override
+    virtual bool on_hotkey(size_t hotkeyId) override
     {
         if (m_enabled)
         {
-            Logger::trace(L"AlwaysOnTop hotkey pressed");
+            Logger::trace(L"AlwaysOnTop hotkey pressed, id={}", hotkeyId);
             if (!is_process_running())
             {
                 Enable();
             }
 
-            SetEvent(m_hPinEvent);
+            if (hotkeyId == 0)
+            {
+                SetEvent(m_hPinEvent);
+            }
+            else if (hotkeyId == 1)
+            {
+                SetEvent(m_hIncreaseOpacityEvent);
+            }
+            else if (hotkeyId == 2)
+            {
+                SetEvent(m_hDecreaseOpacityEvent);
+            }
 
             return true;
         }
@@ -125,19 +136,48 @@ public:
 
     virtual size_t get_hotkeys(Hotkey* hotkeys, size_t buffer_size) override
     {
+        size_t count = 0;
+        
+        // Hotkey 0: Pin/Unpin (e.g., Win+Ctrl+T)
         if (m_hotkey.key)
         {
-            if (hotkeys && buffer_size >= 1)
+            if (hotkeys && buffer_size > count)
             {
-                hotkeys[0] = m_hotkey;
+                hotkeys[count] = m_hotkey;
+                Logger::trace(L"AlwaysOnTop hotkey[0]: win={}, ctrl={}, shift={}, alt={}, key={}", 
+                    m_hotkey.win, m_hotkey.ctrl, m_hotkey.shift, m_hotkey.alt, m_hotkey.key);
             }
+            count++;
+        }
 
-            return 1;
-        }
-        else
+        // Hotkey 1: Increase opacity (same modifiers + VK_OEM_PLUS '=')
+        if (m_hotkey.key)
         {
-            return 0;
+            if (hotkeys && buffer_size > count)
+            {
+                hotkeys[count] = m_hotkey;
+                hotkeys[count].key = VK_OEM_PLUS; // '=' key
+                Logger::trace(L"AlwaysOnTop hotkey[1] (increase opacity): win={}, ctrl={}, shift={}, alt={}, key={}", 
+                    hotkeys[count].win, hotkeys[count].ctrl, hotkeys[count].shift, hotkeys[count].alt, hotkeys[count].key);
+            }
+            count++;
         }
+
+        // Hotkey 2: Decrease opacity (same modifiers + VK_OEM_MINUS '-')
+        if (m_hotkey.key)
+        {
+            if (hotkeys && buffer_size > count)
+            {
+                hotkeys[count] = m_hotkey;
+                hotkeys[count].key = VK_OEM_MINUS; // '-' key
+                Logger::trace(L"AlwaysOnTop hotkey[2] (decrease opacity): win={}, ctrl={}, shift={}, alt={}, key={}", 
+                    hotkeys[count].win, hotkeys[count].ctrl, hotkeys[count].shift, hotkeys[count].alt, hotkeys[count].key);
+            }
+            count++;
+        }
+
+        Logger::trace(L"AlwaysOnTop get_hotkeys returning count={}", count);
+        return count;
     }
 
     // Enable the powertoy
@@ -175,6 +215,8 @@ public:
         app_key = NonLocalizable::ModuleKey;
         m_hPinEvent = CreateDefaultEvent(CommonSharedConstants::ALWAYS_ON_TOP_PIN_EVENT);
         m_hTerminateEvent = CreateDefaultEvent(CommonSharedConstants::ALWAYS_ON_TOP_TERMINATE_EVENT);
+        m_hIncreaseOpacityEvent = CreateDefaultEvent(CommonSharedConstants::ALWAYS_ON_TOP_INCREASE_OPACITY_EVENT);
+        m_hDecreaseOpacityEvent = CreateDefaultEvent(CommonSharedConstants::ALWAYS_ON_TOP_DECREASE_OPACITY_EVENT);
         init_settings();
     }
 
@@ -292,6 +334,8 @@ private:
     // Handle to event used to pin/unpin windows
     HANDLE m_hPinEvent;
     HANDLE m_hTerminateEvent;
+    HANDLE m_hIncreaseOpacityEvent;
+    HANDLE m_hDecreaseOpacityEvent;
 };
 
 extern "C" __declspec(dllexport) PowertoyModuleIface* __cdecl powertoy_create()

src/modules/cmdpal/CommandPalette.slnf

@@ -15,6 +15,7 @@
       "src\\modules\\cmdpal\\Microsoft.CmdPal.UI.ViewModels\\Microsoft.CmdPal.UI.ViewModels.csproj",
       "src\\modules\\cmdpal\\Microsoft.CmdPal.UI\\Microsoft.CmdPal.UI.csproj",
       "src\\modules\\cmdpal\\Microsoft.Terminal.UI\\Microsoft.Terminal.UI.vcxproj",
+      "src\\modules\\cmdpal\\Tests\\Microsoft.CmdPal.Core.Common.UnitTests\\Microsoft.CmdPal.Core.Common.UnitTests.csproj",
       "src\\modules\\cmdpal\\Tests\\Microsoft.CmdPal.Ext.Apps.UnitTests\\Microsoft.CmdPal.Ext.Apps.UnitTests.csproj",
       "src\\modules\\cmdpal\\Tests\\Microsoft.CmdPal.Ext.Bookmarks.UnitTests\\Microsoft.CmdPal.Ext.Bookmarks.UnitTests.csproj",
       "src\\modules\\cmdpal\\Tests\\Microsoft.CmdPal.Ext.Calc.UnitTests\\Microsoft.CmdPal.Ext.Calc.UnitTests.csproj",
@@ -29,6 +30,7 @@
       "src\\modules\\cmdpal\\Tests\\Microsoft.CmdPal.Ext.WindowWalker.UnitTests\\Microsoft.CmdPal.Ext.WindowWalker.UnitTests.csproj",
       "src\\modules\\cmdpal\\Tests\\Microsoft.CmdPal.UI.ViewModels.UnitTests\\Microsoft.CmdPal.UI.ViewModels.UnitTests.csproj",
       "src\\modules\\cmdpal\\Tests\\Microsoft.CmdPal.UITests\\Microsoft.CmdPal.UITests.csproj",
+      "src\\modules\\cmdpal\\Tests\\Microsoft.CommandPalette.Extensions.Toolkit.UnitTests\\Microsoft.CommandPalette.Extensions.Toolkit.UnitTests.csproj",
       "src\\modules\\cmdpal\\ext\\Microsoft.CmdPal.Ext.Apps\\Microsoft.CmdPal.Ext.Apps.csproj",
       "src\\modules\\cmdpal\\ext\\Microsoft.CmdPal.Ext.Bookmark\\Microsoft.CmdPal.Ext.Bookmarks.csproj",
       "src\\modules\\cmdpal\\ext\\Microsoft.CmdPal.Ext.Calc\\Microsoft.CmdPal.Ext.Calc.csproj",

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Microsoft.CmdPal.Core.Common.csproj

@@ -9,4 +9,18 @@
     <PackageReference Include="Microsoft.Extensions.Hosting" />
   </ItemGroup>
 
+  <ItemGroup>
+    <Compile Update="Properties\Resources.Designer.cs">
+      <DesignTime>True</DesignTime>
+      <AutoGen>True</AutoGen>
+      <DependentUpon>Resources.resx</DependentUpon>
+    </Compile>
+  </ItemGroup>
+
+  <ItemGroup>
+    <EmbeddedResource Update="Properties\Resources.resx">
+      <Generator>ResXFileCodeGenerator</Generator>
+    </EmbeddedResource>
+  </ItemGroup>
+
 </Project>

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Properties/Resources.Designer.cs

@@ -0,0 +1,76 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//     Runtime Version:4.0.30319.42000
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+namespace Microsoft.CmdPal.Core.Common.Properties {
+    using System;
+    
+    
+    /// <summary>
+    ///   A strongly-typed resource class, for looking up localized strings, etc.
+    /// </summary>
+    // This class was auto-generated by the StronglyTypedResourceBuilder
+    // class via a tool like ResGen or Visual Studio.
+    // To add or remove a member, edit your .ResX file then rerun ResGen
+    // with the /str option, or rebuild your VS project.
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "18.0.0.0")]
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+    [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
+    internal class Resources {
+        
+        private static global::System.Resources.ResourceManager resourceMan;
+        
+        private static global::System.Globalization.CultureInfo resourceCulture;
+        
+        [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
+        internal Resources() {
+        }
+        
+        /// <summary>
+        ///   Returns the cached ResourceManager instance used by this class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Resources.ResourceManager ResourceManager {
+            get {
+                if (object.ReferenceEquals(resourceMan, null)) {
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Microsoft.CmdPal.Core.Common.Properties.Resources", typeof(Resources).Assembly);
+                    resourceMan = temp;
+                }
+                return resourceMan;
+            }
+        }
+        
+        /// <summary>
+        ///   Overrides the current thread's CurrentUICulture property for all
+        ///   resource lookups using this strongly typed resource class.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Globalization.CultureInfo Culture {
+            get {
+                return resourceCulture;
+            }
+            set {
+                resourceCulture = value;
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to This is an error report generated by Windows Command Palette.
+        ///If you are seeing this, it means something went a little sideways in the app.
+        ///You can help us fix it by filing a report at https://aka.ms/powerToysReportBug.
+        ///
+        ///(While you’re at it, give the details below a quick skim — just to make sure there’s nothing personal you’d prefer not to share. It’s rare, but sometimes little surprises sneak in.).
+        /// </summary>
+        internal static string ErrorReport_Global_Preamble {
+            get {
+                return ResourceManager.GetString("ErrorReport_Global_Preamble", resourceCulture);
+            }
+        }
+    }
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Properties/Resources.resx

@@ -0,0 +1,127 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <data name="ErrorReport_Global_Preamble" xml:space="preserve">
+    <value>This is an error report generated by Windows Command Palette.
+If you are seeing this, it means something went a little sideways in the app.
+You can help us fix it by filing a report at https://aka.ms/powerToysReportBug.
+
+(While you’re at it, give the details below a quick skim — just to make sure there’s nothing personal you’d prefer not to share. It’s rare, but sometimes little surprises sneak in.)</value>
+  </data>
+</root>

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Reports/ErrorReportBuilder.cs

@@ -0,0 +1,118 @@
+// 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.Globalization;
+using System.Runtime.InteropServices;
+using System.Security.Principal;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+using Windows.ApplicationModel;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Reports;
+
+public sealed class ErrorReportBuilder : IErrorReportBuilder
+{
+    private readonly ErrorReportSanitizer _sanitizer = new();
+
+    private static string Preamble => Properties.Resources.ErrorReport_Global_Preamble;
+
+    public string BuildReport(Exception exception, string context, bool redactPii = true)
+    {
+        ArgumentNullException.ThrowIfNull(exception);
+
+        var exceptionMessage = CoalesceExceptionMessage(exception);
+        var sanitizedMessage = redactPii ? _sanitizer.Sanitize(exceptionMessage) : exceptionMessage;
+        var sanitizedFormattedException = redactPii ? _sanitizer.Sanitize(exception.ToString()) : exception.ToString();
+
+        // Note:
+        // - do not localize technical part of the report, we need to ensure it can be read by developers
+        // - keep timestamp format should be consistent with the log (makes it easier to search)
+        var technicalContent =
+               $"""
+                ============================================================
+                Summary:
+                  Message:               {sanitizedMessage}
+                  Type:                  {exception.GetType().FullName}
+                  Source:                {exception.Source ?? "N/A"}
+                  Time:                  {DateTime.Now:yyyy-MM-dd HH:mm:ss.fffffff}
+                  HRESULT:               0x{exception.HResult:X8} ({exception.HResult})
+                  Context:               {context ?? "N/A"}
+
+                Application:
+                  App version:           {GetAppVersionSafe()}
+                  Is elevated:           {GetElevationStatus()}
+
+                Environment:
+                  OS version:            {RuntimeInformation.OSDescription}
+                  OS architecture:       {RuntimeInformation.OSArchitecture}
+                  Runtime identifier:    {RuntimeInformation.RuntimeIdentifier}
+                  Framework:             {RuntimeInformation.FrameworkDescription}
+                  Process architecture:  {RuntimeInformation.ProcessArchitecture}
+                  Culture:               {CultureInfo.CurrentCulture.Name}
+                  UI culture:            {CultureInfo.CurrentUICulture.Name}
+
+                Stack Trace:
+                {exception.StackTrace}
+
+                ------------------ Full Exception Details ------------------
+                {sanitizedFormattedException}
+
+                ============================================================
+                """;
+
+        return $"""
+                {Preamble}
+                {technicalContent}
+                """;
+    }
+
+    private static string GetElevationStatus()
+    {
+        // Note: do not localize technical part of the report, we need to ensure it can be read by developers
+        try
+        {
+            var isElevated = new WindowsPrincipal(WindowsIdentity.GetCurrent()).IsInRole(WindowsBuiltInRole.Administrator);
+            return isElevated ? "yes" : "no";
+        }
+        catch (Exception)
+        {
+            return "Failed to determine elevation status";
+        }
+    }
+
+    private static string GetAppVersionSafe()
+    {
+        // Note: do not localize technical part of the report, we need to ensure it can be read by developers
+        try
+        {
+            var version = Package.Current.Id.Version;
+            return $"{version.Major}.{version.Minor}.{version.Build}.{version.Revision}";
+        }
+        catch (Exception)
+        {
+            return "Failed to retrieve app version";
+        }
+    }
+
+    private static string CoalesceExceptionMessage(Exception exception)
+    {
+        // let's try to get a message from the exception or inferred it from the HRESULT
+        // to show at least something
+        var message = exception.Message;
+        if (string.IsNullOrWhiteSpace(message))
+        {
+            var temp = Marshal.GetExceptionForHR(exception.HResult)?.Message;
+            if (!string.IsNullOrWhiteSpace(temp))
+            {
+                message = temp + $" (inferred from HRESULT 0x{exception.HResult:X8})";
+            }
+        }
+
+        if (string.IsNullOrWhiteSpace(message))
+        {
+            message = "No message available";
+        }
+
+        return message;
+    }
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Reports/IErrorReportBuilder.cs

@@ -0,0 +1,33 @@
+// 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.Common.Services.Reports;
+
+/// <summary>
+/// Defines a contract for creating human-readable error reports from exceptions,
+/// suitable for logs, telemetry, or user-facing diagnostics.
+/// </summary>
+/// <remarks>
+/// Implementations should ensure reports are consistent and optionally redact
+/// personally identifiable or sensitive information when requested.
+/// </remarks>
+public interface IErrorReportBuilder
+{
+    /// <summary>
+    /// Builds a formatted error report for the specified <paramref name="exception"/> and <paramref name="context"/>.
+    /// </summary>
+    /// <param name="exception">The exception that triggered the error report.</param>
+    /// <param name="context">
+    /// A short, human-readable description of where or what was being executed when the error occurred
+    /// (e.g., the operation name, component, or scenario).
+    /// </param>
+    /// <param name="redactPii">
+    /// When true, attempts to remove or obfuscate personally identifiable or sensitive information
+    /// (such as file paths, emails, machine/usernames, tokens). Defaults to true.
+    /// </param>
+    /// <returns>
+    /// A formatted string containing the error report, suitable for logging or telemetry submission.
+    /// </returns>
+    string BuildReport(Exception exception, string context, bool redactPii = true);
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/Abstraction/ITextSanitizer.cs

@@ -0,0 +1,61 @@
+// 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.Common.Services.Sanitizer.Abstraction;
+
+/// <summary>
+/// Defines a service that sanitizes text by applying a set of configurable, regex-based rules.
+/// Typical use cases include masking secrets, removing PII, or normalizing logs.
+/// </summary>
+/// <remarks>
+/// - Rules are applied in their registered order; rule ordering may affect the final output.
+/// - Each rule should have a unique <c>description</c> that acts as its identifier.
+/// </remarks>
+/// <seealso cref="SanitizationRule"/>
+public interface ITextSanitizer
+{
+    /// <summary>
+    /// Sanitizes the specified input by applying all registered rules in order.
+    /// </summary>
+    /// <param name="input">The input text to sanitize. Implementations should handle <see langword="null"/> safely.</param>
+    /// <returns>The sanitized text after all rules are applied.</returns>
+    string Sanitize(string? input);
+
+    /// <summary>
+    /// Adds a sanitization rule using a .NET regular expression pattern and a replacement string.
+    /// </summary>
+    /// <param name="pattern">A .NET regular expression pattern used to match text to sanitize.</param>
+    /// <param name="replacement">
+    /// The replacement text used by <c>Regex.Replace</c>. Supports standard regex replacement tokens,
+    /// including numbered groups (<c>$1</c>) and named groups (<c>${name}</c>).
+    /// </param>
+    /// <param name="description">
+    /// A human-readable, unique identifier for the rule. Used to list, test, and remove the rule.
+    /// </param>
+    /// <remarks>
+    /// Implementations typically validate <paramref name="pattern"/> is a valid regex and may reject duplicate <paramref name="description"/> values.
+    /// </remarks>
+    void AddRule(string pattern, string replacement, string description = "");
+
+    /// <summary>
+    /// Removes a previously added rule identified by its <paramref name="description"/>.
+    /// </summary>
+    /// <param name="description">The unique description of the rule to remove.</param>
+    void RemoveRule(string description);
+
+    /// <summary>
+    /// Gets a read-only snapshot of the currently registered sanitization rules in application order.
+    /// </summary>
+    /// <returns>A read-only list of <see cref="SanitizationRule"/> items.</returns>
+    IReadOnlyList<SanitizationRule> GetRules();
+
+    /// <summary>
+    /// Tests a single rule, identified by <paramref name="ruleDescription"/>, against the provided <paramref name="input"/>,
+    /// without applying other rules.
+    /// </summary>
+    /// <param name="input">The input text to test.</param>
+    /// <param name="ruleDescription">The description (identifier) of the rule to test.</param>
+    /// <returns>The result of applying only the specified rule to the input.</returns>
+    string TestRule(string input, string ruleDescription);
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/Abstraction/SanitizationRule.cs

@@ -0,0 +1,36 @@
+// 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.Text.RegularExpressions;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+public readonly record struct SanitizationRule
+{
+    public SanitizationRule(Regex regex, string replacement, string description = "")
+    {
+        Regex = regex;
+        Replacement = replacement;
+        Evaluator = null;
+        Description = description;
+    }
+
+    public SanitizationRule(Regex regex, MatchEvaluator evaluator, string description = "")
+    {
+        Regex = regex;
+        Evaluator = evaluator;
+        Replacement = null;
+        Description = description;
+    }
+
+    public Regex Regex { get; }
+
+    public string? Replacement { get; }
+
+    public MatchEvaluator? Evaluator { get; }
+
+    public string Description { get; }
+
+    public override string ToString() => $"{Description}: {Regex} -> {Replacement ?? "<evaluator>"}";
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/ConnectionStringRuleProvider.cs

@@ -0,0 +1,20 @@
+// 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.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal sealed partial class ConnectionStringRuleProvider : ISanitizationRuleProvider
+{
+    [GeneratedRegex(@"(Server|Data Source|Initial Catalog|Database|User ID|Username|Password|Pwd|Uid)\s*=\s*(?:""[^""]*""|'[^']*'|[^;,\s]+)",
+        SanitizerDefaults.DefaultOptions, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex ConnectionParamRx();
+
+    public IEnumerable<SanitizationRule> GetRules()
+    {
+        yield return new(ConnectionParamRx(), "$1=[REDACTED]", "Connection string parameters");
+    }
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/EnvironmentPropertiesRuleProvider.cs

@@ -0,0 +1,32 @@
+// 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.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal sealed class EnvironmentPropertiesRuleProvider : ISanitizationRuleProvider
+{
+    public IEnumerable<SanitizationRule> GetRules()
+    {
+        List<SanitizationRule> rules = [];
+
+        var machine = Environment.MachineName;
+        if (!string.IsNullOrWhiteSpace(machine))
+        {
+            var rx = new Regex(@"\b" + Regex.Escape(machine) + @"\b", SanitizerDefaults.DefaultOptions, TimeSpan.FromMilliseconds(SanitizerDefaults.DefaultMatchTimeoutMs));
+            rules.Add(new(rx, "[MACHINE_NAME_REDACTED]", "Machine name"));
+        }
+
+        var domain = Environment.UserDomainName;
+        if (!string.IsNullOrWhiteSpace(domain))
+        {
+            var rx = new Regex(@"\b" + Regex.Escape(domain) + @"\b", SanitizerDefaults.DefaultOptions, TimeSpan.FromMilliseconds(SanitizerDefaults.DefaultMatchTimeoutMs));
+            rules.Add(new(rx, "[USER_DOMAIN_NAME_REDACTED]", "User domain name"));
+        }
+
+        return rules;
+    }
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/ErrorReportSanitizer.cs

@@ -0,0 +1,85 @@
+// 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 Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+/// <summary>
+/// Specific sanitizer used for error report content. Builds on top of the generic TextSanitizer.
+/// </summary>
+public sealed class ErrorReportSanitizer
+{
+    private readonly TextSanitizer _sanitizer = new(BuildProviders(), onGuardrailTriggered: OnGuardrailTriggered);
+
+    private static void OnGuardrailTriggered(GuardrailEventArgs eventArgs)
+    {
+        var msg = $"Sanitization guardrail triggered for rule '{eventArgs.RuleDescription}': original length={eventArgs.OriginalLength}, result length={eventArgs.ResultLength}, ratio={eventArgs.Ratio:F2}, threshold={eventArgs.Threshold:F2}";
+        CoreLogger.LogDebug(msg);
+    }
+
+    private static IEnumerable<ISanitizationRuleProvider> BuildProviders()
+    {
+        // Order matters
+        return
+        [
+            new PiiRuleProvider(),
+            new UrlRuleProvider(),
+            new NetworkRuleProvider(),
+            new TokenRuleProvider(),
+            new ConnectionStringRuleProvider(),
+            new SecretKeyValueRulesProvider(),
+            new EnvironmentPropertiesRuleProvider(),
+            new FilenameMaskRuleProvider(),
+            new ProfilePathAndUsernameRuleProvider()
+        ];
+    }
+
+    public string Sanitize(string? input) => _sanitizer.Sanitize(input);
+
+    public string SanitizeException(Exception? exception)
+    {
+        if (exception is null)
+        {
+            return string.Empty;
+        }
+
+        var fullMessage = GetFullExceptionMessage(exception);
+        return Sanitize(fullMessage);
+    }
+
+    private static string GetFullExceptionMessage(Exception exception)
+    {
+        List<string> messages = [];
+        var current = exception;
+        var depth = 0;
+
+        // Prevent infinite loops on pathological InnerException graphs
+        while (current is not null && depth < 10)
+        {
+            messages.Add($"{current.GetType().Name}: {current.Message}");
+
+            if (!string.IsNullOrEmpty(current.StackTrace))
+            {
+                messages.Add($"Stack Trace: {current.StackTrace}");
+            }
+
+            current = current.InnerException;
+            depth++;
+        }
+
+        return string.Join(Environment.NewLine, messages);
+    }
+
+    public void AddRule(string pattern, string replacement, string description = "")
+        => _sanitizer.AddRule(pattern, replacement, description);
+
+    public void RemoveRule(string description)
+        => _sanitizer.RemoveRule(description);
+
+    public IReadOnlyList<SanitizationRule> GetRules() => _sanitizer.GetRules();
+
+    public string TestRule(string input, string ruleDescription)
+        => _sanitizer.TestRule(input, ruleDescription);
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/FilenameMaskRuleProvider.cs

@@ -0,0 +1,109 @@
+// 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.Collections.Frozen;
+using System.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal sealed class FilenameMaskRuleProvider : ISanitizationRuleProvider
+{
+    private static readonly FrozenSet<string> CommonFileStemExclusions = new[]
+    {
+        "settings",
+        "config",
+        "configuration",
+        "appsettings",
+        "options",
+        "prefs",
+        "preferences",
+        "squirrel",
+        "app",
+        "system",
+        "env",
+        "environment",
+        "manifest",
+    }.ToFrozenSet(StringComparer.OrdinalIgnoreCase);
+
+    public IEnumerable<SanitizationRule> GetRules()
+    {
+        const string pattern = """
+        (?<full>
+            (?: [A-Za-z]: )? (?: [\\/][^\\/:*?""<>|\s]+ )+       # drive-rooted or UNC-like
+          |     [^\\/:*?""<>|\s]+ (?: [\\/][^\\/:*?""<>|\s]+ )+  # relative with at least one sep
+        )
+        """;
+
+        var rx = new Regex(pattern, SanitizerDefaults.DefaultOptions | RegexOptions.IgnorePatternWhitespace, TimeSpan.FromMilliseconds(SanitizerDefaults.DefaultMatchTimeoutMs));
+        yield return new SanitizationRule(rx, MatchEvaluator, "Mask filename in any path");
+        yield break;
+
+        static string MatchEvaluator(Match m)
+        {
+            var full = m.Groups["full"].Value;
+
+            var lastSep = Math.Max(full.LastIndexOf('\\'), full.LastIndexOf('/'));
+            if (lastSep < 0 || lastSep == full.Length - 1)
+            {
+                return full;
+            }
+
+            var dir = full[..(lastSep + 1)];
+            var file = full[(lastSep + 1)..];
+
+            var dot = file.LastIndexOf('.');
+            var looksLikeFile = (dot > 0 && dot < file.Length - 1) || (file.StartsWith('.') && file.Length > 1);
+
+            if (!looksLikeFile)
+            {
+                return full;
+            }
+
+            string stem, ext;
+            if (dot > 0 && dot < file.Length - 1)
+            {
+                stem = file[..dot];
+                ext = file[dot..];
+            }
+            else
+            {
+                stem = file;
+                ext = string.Empty;
+            }
+
+            if (!ShouldMaskFileName(stem))
+            {
+                return dir + file;
+            }
+
+            var masked = MaskStem(stem) + ext;
+            return dir + masked;
+        }
+    }
+
+    private static string NormalizeStem(string stem)
+    {
+        return stem.Replace("-", string.Empty, StringComparison.Ordinal)
+            .Replace("_", string.Empty, StringComparison.Ordinal)
+            .Replace(".", string.Empty, StringComparison.Ordinal);
+    }
+
+    private static bool ShouldMaskFileName(string stem)
+    {
+        return !CommonFileStemExclusions.Contains(NormalizeStem(stem));
+    }
+
+    private static string MaskStem(string stem)
+    {
+        if (string.IsNullOrEmpty(stem))
+        {
+            return stem;
+        }
+
+        var keep = Math.Min(2, stem.Length);
+        var maskedCount = Math.Max(1, stem.Length - keep);
+        return stem[..keep] + new string('*', maskedCount);
+    }
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/GuardrailEventArgs.cs

@@ -0,0 +1,14 @@
+// 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.Common.Services.Sanitizer;
+
+public record GuardrailEventArgs(
+    string RuleDescription,
+    int OriginalLength,
+    int ResultLength,
+    double Threshold)
+{
+    public double Ratio => OriginalLength > 0 ? (double)ResultLength / OriginalLength : 1.0;
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/ISanitizationRuleProvider.cs

@@ -0,0 +1,12 @@
+// 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 Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal interface ISanitizationRuleProvider
+{
+    IEnumerable<SanitizationRule> GetRules();
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/NetworkRuleProvider.cs

@@ -0,0 +1,84 @@
+// 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.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal sealed partial class NetworkRuleProvider : ISanitizationRuleProvider
+{
+    public IEnumerable<SanitizationRule> GetRules()
+    {
+        yield return new(Ipv4Rx(), "[IP4_REDACTED]", "IP addresses");
+        yield return new(Ipv6BracketedRx(), "[IP6_REDACTED]", "IPv6 addresses (bracketed/with port)");
+        yield return new(Ipv6Rx(), "[IP6_REDACTED]", "IPv6 addresses");
+        yield return new(MacAddressRx(), "[MAC_ADDRESS_REDACTED]", "MAC addresses");
+    }
+
+    [GeneratedRegex(@"\b(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\b",
+        SanitizerDefaults.DefaultOptions, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex Ipv4Rx();
+
+    [GeneratedRegex(
+        """
+        (?ix)                                  # ignore case/whitespace
+              (?<![A-F0-9:])                        # left edge
+              (
+                (?:[A-F0-9]{1,4}:){7}[A-F0-9]{1,4}                | # 1:2:3:4:5:6:7:8
+                (?:[A-F0-9]{1,4}:){1,7}:                           | # 1:: 1:2:...:7::
+                (?:[A-F0-9]{1,4}:){1,6}:[A-F0-9]{1,4}             |
+                (?:[A-F0-9]{1,4}:){1,5}(?::[A-F0-9]{1,4}){1,2}    |
+                (?:[A-F0-9]{1,4}:){1,4}(?::[A-F0-9]{1,4}){1,3}    |
+                (?:[A-F0-9]{1,4}:){1,3}(?::[A-F0-9]{1,4}){1,4}    |
+                (?:[A-F0-9]{1,4}:){1,2}(?::[A-F0-9]{1,4}){1,5}    |
+                [A-F0-9]{1,4}:(?::[A-F0-9]{1,4}){1,6}             |
+                :(?::[A-F0-9]{1,4}){1,7}                          | # ::, ::1, etc.
+                (?:[A-F0-9]{1,4}:){6}\d{1,3}(?:\.\d{1,3}){3}      | # IPv4 tail
+                (?:[A-F0-9]{1,4}:){1,5}:(?:\d{1,3}\.){3}\d{1,3}   |
+                (?:[A-F0-9]{1,4}:){1,4}:(?:\d{1,3}\.){3}\d{1,3}   |
+                (?:[A-F0-9]{1,4}:){1,3}:(?:\d{1,3}\.){3}\d{1,3}   |
+                (?:[A-F0-9]{1,4}:){1,2}:(?:\d{1,3}\.){3}\d{1,3}   |
+                [A-F0-9]{1,4}:(?:\d{1,3}\.){3}\d{1,3}             |
+                :(?:\d{1,3}\.){3}\d{1,3}
+              )
+              (?:%\w+)?                               # optional zone id
+              (?![A-F0-9:])                           # right edge
+        """,
+        SanitizerDefaults.DefaultOptions | RegexOptions.IgnorePatternWhitespace, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex Ipv6Rx();
+
+    [GeneratedRegex(
+        """
+    (?ix)
+          \[
+            (
+              (?:[A-F0-9]{1,4}:){7}[A-F0-9]{1,4}              |
+              (?:[A-F0-9]{1,4}:){1,7}:                         |
+              (?:[A-F0-9]{1,4}:){1,6}:[A-F0-9]{1,4}           |
+              (?:[A-F0-9]{1,4}:){1,5}(?::[A-F0-9]{1,4}){1,2}  |
+              (?:[A-F0-9]{1,4}:){1,4}(?::[A-F0-9]{1,4}){1,3}  |
+              (?:[A-F0-9]{1,4}:){1,3}(?::[A-F0-9]{1,4}){1,4}  |
+              (?:[A-F0-9]{1,4}:){1,2}(?::[A-F0-9]{1,4}){1,5}  |
+              [A-F0-9]{1,4}:(?::[A-F0-9]{1,4}){1,6}           |
+              :(?::[A-F0-9]{1,4}){1,7}                        |
+              (?:[A-F0-9]{1,4}:){6}\d{1,3}(?:\.\d{1,3}){3}    |
+              (?:[A-F0-9]{1,4}:){1,5}:(?:\d{1,3}\.){3}\d{1,3} |
+              (?:[A-F0-9]{1,4}:){1,4}:(?:\d{1,3}\.){3}\d{1,3} |
+              (?:[A-F0-9]{1,4}:){1,3}:(?:\d{1,3}\.){3}\d{1,3} |
+              (?:[A-F0-9]{1,4}:){1,2}:(?:\d{1,3}\.){3}\d{1,3} |
+              [A-F0-9]{1,4}:(?:\d{1,3}\.){3}\d{1,3}           |
+              :(?:\d{1,3}\.){3}\d{1,3}
+            )
+            (?:%\w+)?                          # optional zone id
+          \]
+          (?: : (?<port>\d{1,5}) )?            # optional port
+    """,
+        SanitizerDefaults.DefaultOptions | RegexOptions.IgnorePatternWhitespace, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex Ipv6BracketedRx();
+
+    [GeneratedRegex(@"\b(?:[0-9A-Fa-f]{2}[:-]){5}(?:[0-9A-Fa-f]{2}|[0-9A-Fa-f]{1,2})\b",
+        SanitizerDefaults.DefaultOptions, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex MacAddressRx();
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/PiiRuleProvider.cs

@@ -0,0 +1,83 @@
+// 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.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal sealed partial class PiiRuleProvider : ISanitizationRuleProvider
+{
+    public IEnumerable<SanitizationRule> GetRules()
+    {
+        yield return new(EmailRx(), "[EMAIL_REDACTED]", "Email addresses");
+        yield return new(SsnRx(), "[SSN_REDACTED]", "Social Security Numbers");
+        yield return new(CreditCardRx(), "[CARD_REDACTED]", "Credit card numbers");
+
+        // phone number regex is the most generic, so it goes last
+        // we can't make this too generic; otherwise we over-redact error codes, dates, etc.
+        yield return new(PhoneRx(), "[PHONE_REDACTED]", "Phone numbers");
+    }
+
+    [GeneratedRegex(@"\b[a-zA-Z0-9]([a-zA-Z0-9._%-]*[a-zA-Z0-9])?@[a-zA-Z0-9]([a-zA-Z0-9.-]*[a-zA-Z0-9])?\.[a-zA-Z]{2,}\b",
+        SanitizerDefaults.DefaultOptions, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex EmailRx();
+
+    [GeneratedRegex("""
+                    (?xi)
+                    # ---------- boundaries ----------
+                    (?<!\w)                          # not after a letter/digit/underscore
+                    (?<![A-Za-z0-9]-)                # avoid starting inside hyphenated tokens (GUID middles, etc.)
+
+                    # ---------- global do-not-match guards ----------
+                    (?!                              # ISO date (yyyy-mm-dd / yyyy.mm.dd / yyyy/mm/dd)
+                       (?:19|20)\d{2}[-./](?:0[1-9]|1[0-2])[-./](?:0[1-9]|[12]\d|3[01])\b
+                    )
+                    (?!                              # EU date (dd-mm-yyyy / dd.mm.yyyy / dd/mm/yyyy)
+                       (?:0[1-9]|[12]\d|3[01])[-./](?:0[1-9]|1[0-2])[-./](?:19|20)\d{2}\b
+                    )
+                    (?!                              # ISO datetime like 2025-08-24T14:32[:ss][Z|±hh:mm]
+                       (?:19|20)\d{2}-\d{2}-\d{2}[T\s]\d{2}:\d{2}(?::\d{2})?(?:Z|[+-]\d{2}:\d{2})?\b
+                    )
+                    (?!\b(?:\d{1,3}\.){3}\d{1,3}(?::\d{1,5})?\b)   # IPv4 with optional :port
+                    (?!\b[0-9a-f]{8}-(?:[0-9a-f]{4}-){3}[0-9a-f]{12}\b)  # GUID, lowercase
+                    (?!\b[0-9A-F]{8}-(?:[0-9A-F]{4}-){3}[0-9A-F]{12}\b)  # GUID, uppercase
+                    (?!\bv?\d+(?:\.\d+){2,}\b)       # semantic/file versions like 1.2.3 or 10.0.22631.3448
+                    (?!\b(?:[0-9A-F]{2}[:-]){5}[0-9A-F]{2}\b)       # MAC address
+
+                    # ---------- digit budget ----------
+                    (?=(?:\D*\d){7,15})              # 7–15 digits in total
+
+                    # ---------- number body ----------
+                    (?:
+                      # A with explicit country code, allow compact digits (E.164-ish) or grouped
+                      (?:\+|00)[1-9]\d{0,2}
+                      (?:
+                        [\p{Zs}.\-\/]*\d{6,14}
+                        |
+                        [\p{Zs}.\-\/]* (?:\(\d{1,4}\)|\d{1,4})
+                        (?:[\p{Zs}.\-\/]+(?:\(\d{2,4}\)|\d{2,4})){1,6}
+                      )
+                      |
+                      # B no country code => require separators between blocks (avoid plain big ints)
+                      (?:\(\d{1,4}\)|\d{1,4})
+                      (?:[\p{Zs}.\-\/]+(?:\(\d{2,4}\)|\d{2,4})){1,6}
+                    )
+
+                    # ---------- optional extension ----------
+                    (?:[\p{Zs}.\-,:;]* (?:ext\.?|x) [\p{Zs}]* (?<ext>\d{1,6}))?
+
+                    (?!-\w)                           # don't end just before '-letter'/'-digit'
+                    """,
+        SanitizerDefaults.DefaultOptions | RegexOptions.IgnorePatternWhitespace, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex PhoneRx();
+
+    [GeneratedRegex(@"\b\d{3}-\d{2}-\d{4}\b",
+        SanitizerDefaults.DefaultOptions, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex SsnRx();
+
+    [GeneratedRegex(@"\b\d{4}[-\s]?\d{4}[-\s]?\d{4}[-\s]?\d{4}\b",
+        SanitizerDefaults.DefaultOptions, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex CreditCardRx();
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/ProfilePathAndUsernameRuleProvider.cs

@@ -0,0 +1,155 @@
+// 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.Collections.Frozen;
+using System.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal sealed class ProfilePathAndUsernameRuleProvider : ISanitizationRuleProvider
+{
+    private static readonly TimeSpan DefaultTimeout = TimeSpan.FromMilliseconds(SanitizerDefaults.DefaultMatchTimeoutMs);
+
+    private readonly Dictionary<string, string> _profilePaths = new(StringComparer.OrdinalIgnoreCase);
+    private readonly HashSet<string> _usernames = new(StringComparer.OrdinalIgnoreCase);
+
+    private static readonly FrozenSet<string> CommonPathParts = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+    {
+        "Users", "home", "Documents", "Desktop", "AppData", "Local", "Roaming",
+        "Pictures", "Videos", "Music", "Downloads", "Program Files", "Windows",
+        "System32", "bin", "usr", "var", "etc", "opt", "tmp",
+    }.ToFrozenSet(StringComparer.OrdinalIgnoreCase);
+
+    private static readonly FrozenSet<string> CommonWords = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+    {
+        "admin", "user", "test", "guest", "public", "system", "service",
+        "default", "temp", "local", "shared", "common", "data", "config",
+    }.ToFrozenSet(StringComparer.OrdinalIgnoreCase);
+
+    public ProfilePathAndUsernameRuleProvider()
+    {
+        DetectSystemPaths();
+    }
+
+    public IEnumerable<SanitizationRule> GetRules()
+    {
+        List<SanitizationRule> rules = [];
+
+        // Profile path rules (ordered longest-first)
+        var orderedRules = _profilePaths
+            .Where(p => !string.IsNullOrEmpty(p.Key))
+            .OrderByDescending(p => p.Key.Length);
+
+        foreach (var profilePath in orderedRules)
+        {
+            try
+            {
+                var normalizedPath = profilePath.Key
+                    .Replace('/', Path.DirectorySeparatorChar)
+                    .Replace('\\', Path.DirectorySeparatorChar);
+                var escapedPath = Regex.Escape(normalizedPath);
+
+                var pattern = escapedPath + @"(?:[/\\]*)";
+                var rx = new Regex(pattern, SanitizerDefaults.DefaultOptions, DefaultTimeout);
+
+                rules.Add(new(rx, profilePath.Value, $"Profile path: {profilePath}"));
+            }
+            catch
+            {
+                // Skip problematic paths
+            }
+        }
+
+        // Username rules
+        foreach (var username in _usernames.Where(u => !string.IsNullOrEmpty(u) && u.Length > 2))
+        {
+            try
+            {
+                if (!IsLikelyUsername(username))
+                {
+                    continue;
+                }
+
+                var rx = new Regex(@"\b" + Regex.Escape(username) + @"\b", SanitizerDefaults.DefaultOptions, DefaultTimeout);
+                rules.Add(new(rx, "[USERNAME_REDACTED]", $"Username: {username}"));
+            }
+            catch
+            {
+                // Skip problematic usernames
+            }
+        }
+
+        return rules;
+    }
+
+    public IReadOnlyDictionary<string, string> GetDetectedProfilePaths() => _profilePaths;
+
+    public IReadOnlyCollection<string> GetDetectedUsernames() => _usernames;
+
+    private void DetectSystemPaths()
+    {
+        try
+        {
+            var userProfile = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile);
+            if (!string.IsNullOrEmpty(userProfile) && Directory.Exists(userProfile))
+            {
+                _profilePaths.Add(userProfile, "[USER_PROFILE_DIR]");
+                var username = Path.GetFileName(userProfile);
+                if (!string.IsNullOrEmpty(username) && username.Length > 2)
+                {
+                    _usernames.Add(username);
+                }
+            }
+
+            Environment.SpecialFolder[] profileFolders =
+            [
+                Environment.SpecialFolder.ApplicationData,
+                Environment.SpecialFolder.LocalApplicationData,
+                Environment.SpecialFolder.Desktop,
+                Environment.SpecialFolder.MyDocuments,
+                Environment.SpecialFolder.MyPictures,
+                Environment.SpecialFolder.MyVideos,
+                Environment.SpecialFolder.MyMusic,
+                Environment.SpecialFolder.StartMenu,
+                Environment.SpecialFolder.Startup,
+                Environment.SpecialFolder.DesktopDirectory
+            ];
+
+            foreach (var folder in profileFolders)
+            {
+                var dir = Environment.GetFolderPath(folder);
+                if (string.IsNullOrEmpty(dir))
+                {
+                    continue;
+                }
+
+                var added = _profilePaths.TryAdd(dir, $"[{folder.ToString().ToUpperInvariant()}_DIR]");
+                if (!added)
+                {
+                    continue;
+                }
+            }
+
+            string[] envVars = ["USERPROFILE", "HOME", "OneDrive", "OneDriveCommercial"];
+            foreach (var envVar in envVars)
+            {
+                var envPath = Environment.GetEnvironmentVariable(envVar);
+                if (!string.IsNullOrEmpty(envPath) && Directory.Exists(envPath))
+                {
+                    _profilePaths.TryAdd(envPath, $"[{envVar.ToUpperInvariant()}_DIR]");
+                }
+            }
+        }
+        catch (Exception ex)
+        {
+            CoreLogger.LogError("Error detecting system profile paths and usernames", ex);
+        }
+    }
+
+    private static bool IsLikelyUsername(string username) =>
+        !CommonWords.Contains(username) &&
+        username.Length is >= 3 and <= 50 &&
+        !username.All(char.IsDigit);
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/SanitizerDefaults.cs

@@ -0,0 +1,13 @@
+// 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.Text.RegularExpressions;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal static class SanitizerDefaults
+{
+    public const RegexOptions DefaultOptions = RegexOptions.IgnoreCase | RegexOptions.CultureInvariant | RegexOptions.Compiled;
+    public const int DefaultMatchTimeoutMs = 100;
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/SecretKeyValueRulesProvider.cs

@@ -0,0 +1,172 @@
+// 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.Collections.Frozen;
+using System.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal sealed class SecretKeyValueRulesProvider : ISanitizationRuleProvider
+{
+    // Central list of common secret keys/phrases to redact when found in key=value pairs.
+    private static readonly FrozenSet<string> SecretKeys = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+    {
+        // Core passwords/secrets
+        "password",
+        "passphrase",
+        "passwd",
+        "pwd",
+
+        // Tokens
+        "token",
+        "access token",
+        "refresh token",
+        "id token",
+        "auth token",
+        "session token",
+        "bearer token",
+        "personal access token",
+        "pat",
+
+        // API / client credentials
+        "api key",
+        "api secret",
+        "x api key",
+        "client id",
+        "client secret",
+        "x client id",
+        "x client secret",
+        "consumer secret",
+        "service principal secret",
+
+        // Cloud & platform (Azure/AppInsights/etc.)
+        "subscription key",
+        "instrumentation key",
+        "account key",
+        "storage account key",
+        "shared access key",
+        "shared access signature",
+        "SAS token",
+
+        // Connection strings (often surfaced in exception messages)
+        "connection string",
+        "conn string",
+        "storage connection string",
+
+        // Certificates & crypto
+        "private key",
+        "certificate password",
+        "client certificate password",
+        "pfx password",
+
+        // AWS common keys
+        "aws access key id",
+        "aws secret access key",
+        "aws session token",
+
+        // Optional service aliases
+        "cosmos db key",
+    }.ToFrozenSet(StringComparer.OrdinalIgnoreCase);
+
+    public IEnumerable<SanitizationRule> GetRules()
+    {
+        yield return BuildSecretKeyValueRule(
+            SecretKeys,
+            timeout: TimeSpan.FromSeconds(5),
+            starEverything: true);
+    }
+
+    private static SanitizationRule BuildSecretKeyValueRule(
+        IEnumerable<string> keys,
+        RegexOptions? options = null,
+        TimeSpan? timeout = null,
+        string label = "[REDACTED]",
+        bool treatDashUnderscoreAsSpace = true,
+        string separatorsClass = "[:=]",     // char class for separators
+        string unquotedStopClass = "\\s",
+        bool starEverything = false)
+    {
+        ArgumentNullException.ThrowIfNull(keys);
+
+        // Between-word matcher for keys: "api key" -> "api\s*key" (optionally treating _/- as "space")
+        var between = treatDashUnderscoreAsSpace ? @"(?:\s|[_-])*" : @"\s*";
+
+        var patterns = new List<string>();
+
+        foreach (var raw in keys)
+        {
+            var key = raw?.Trim();
+            if (string.IsNullOrEmpty(key))
+            {
+                continue;
+            }
+
+            if (starEverything && key is not ['*', ..])
+            {
+                key = "*" + key;
+            }
+
+            if (key is ['*', .. var tail])
+            {
+                // Wildcard prefix: allow one non-space token + optional "-" or "_" before the remainder.
+                // Matches: "api key", "api-key", "azure-api-key", "user_api_key"
+                var remainder = tail.Trim();
+                if (remainder.Length == 0)
+                {
+                    continue;
+                }
+
+                var rem = Normalize(remainder, between);
+                patterns.Add($@"(?:(?>[A-Za-z0-9_]{{1,128}}[_-]))?{rem}");
+            }
+            else
+            {
+                patterns.Add(Normalize(key, between));
+            }
+        }
+
+        if (patterns.Count == 0)
+        {
+            throw new ArgumentException("No non-empty keys provided.", nameof(keys));
+        }
+
+        var keysAlt = string.Join("|", patterns);
+
+        var pattern =
+            $"""
+             # Negative lookbehind to ensure the key is not part of a larger word
+             (?<![A-Za-z0-9])
+             # Match and capture the key (from the provided list)
+             (?<key>(?:{keysAlt}))
+             # Negative lookahead to ensure the key is not part of a larger word
+             (?![A-Za-z0-9])
+             # Optional whitespace between key and separator
+             \s*
+             # Separator (e.g., ':' or '=')
+             (?<sep>{separatorsClass})
+             # Optional whitespace after separator
+             \s*
+             # Match and capture the value, supporting quoted or unquoted values
+             (?:
+                 # Quoted value: match opening quote, value, and closing quote
+                 (?<q>["'])(?<val>[^"']+)\k<q>
+                 |
+                 # Unquoted value: match up to the next whitespace
+                 (?<val>[^{unquotedStopClass}]+)
+             )
+             """;
+
+        var rx = new Regex(
+            pattern,
+            (options ?? (RegexOptions.IgnoreCase | RegexOptions.CultureInvariant)) | RegexOptions.IgnorePatternWhitespace,
+            timeout ?? TimeSpan.FromMilliseconds(1000));
+
+        var replacement = @"${key}${sep} ${q}" + label + @"${q}";
+        return new SanitizationRule(rx, replacement, "Sensitive key/value pairs");
+
+        static string Normalize(string s, string betweenSep)
+            => Regex.Escape(s).Replace("\\ ", betweenSep);
+    }
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/TextSanitizer.cs

@@ -0,0 +1,135 @@
+// 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.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+/// <summary>
+/// Generic text sanitizer that applies a sequence of regex-based rules over input text.
+/// </summary>
+internal sealed class TextSanitizer : ITextSanitizer
+{
+    // Default guardrail: sanitized text must retain at least 30% of the original length
+    private const double DefaultGuardrailThreshold = 0.3;
+    private static readonly TimeSpan DefaultTimeout = TimeSpan.FromMilliseconds(SanitizerDefaults.DefaultMatchTimeoutMs);
+
+    private readonly List<SanitizationRule> _rules = [];
+    private readonly double _guardrailThreshold;
+    private readonly Action<GuardrailEventArgs>? _onGuardrailTriggered;
+
+    public TextSanitizer(
+        double guardrailThreshold = DefaultGuardrailThreshold,
+        Action<GuardrailEventArgs>? onGuardrailTriggered = null)
+    {
+        _guardrailThreshold = guardrailThreshold;
+        _onGuardrailTriggered = onGuardrailTriggered;
+    }
+
+    public TextSanitizer(
+        IEnumerable<ISanitizationRuleProvider> providers,
+        double guardrailThreshold = DefaultGuardrailThreshold,
+        Action<GuardrailEventArgs>? onGuardrailTriggered = null)
+    {
+        ArgumentNullException.ThrowIfNull(providers);
+        _guardrailThreshold = guardrailThreshold;
+        _onGuardrailTriggered = onGuardrailTriggered;
+
+        foreach (var p in providers)
+        {
+            try
+            {
+                _rules.AddRange(p.GetRules());
+            }
+            catch
+            {
+                // Best-effort; ignore provider errors
+            }
+        }
+    }
+
+    public string Sanitize(string? input)
+    {
+        if (string.IsNullOrEmpty(input))
+        {
+            return input ?? string.Empty;
+        }
+
+        var result = input;
+
+        foreach (var rule in _rules)
+        {
+            try
+            {
+                var previous = result;
+
+                result = rule.Evaluator is null
+                    ? rule.Regex.Replace(previous, rule.Replacement!)
+                    : rule.Regex.Replace(previous, rule.Evaluator);
+
+                if (result.Length < previous.Length * _guardrailThreshold)
+                {
+                    _onGuardrailTriggered?.Invoke(new GuardrailEventArgs(
+                        rule.Description,
+                        previous.Length,
+                        result.Length,
+                        _guardrailThreshold));
+                    result = previous; // Guardrail
+                }
+            }
+            catch (RegexMatchTimeoutException)
+            {
+                // Ignore timeouts; keep the original input
+            }
+            catch
+            {
+                // Ignore other exceptions; keep the original input
+            }
+        }
+
+        return result;
+    }
+
+    public void AddRule(string pattern, string replacement, string description = "")
+    {
+        var rx = new Regex(pattern, SanitizerDefaults.DefaultOptions, DefaultTimeout);
+        _rules.Add(new SanitizationRule(rx, replacement, description));
+    }
+
+    public void RemoveRule(string description)
+    {
+        _rules.RemoveAll(r => r.Description.Equals(description, StringComparison.OrdinalIgnoreCase));
+    }
+
+    public IReadOnlyList<SanitizationRule> GetRules() => _rules.AsReadOnly();
+
+    public string TestRule(string input, string ruleDescription)
+    {
+        var rule = _rules.FirstOrDefault(r => r.Description.Contains(ruleDescription, StringComparison.OrdinalIgnoreCase));
+        if (rule.Regex is null)
+        {
+            return input;
+        }
+
+        try
+        {
+            if (rule.Evaluator is not null)
+            {
+                return rule.Regex.Replace(input, rule.Evaluator);
+            }
+
+            if (rule.Replacement is not null)
+            {
+                return rule.Regex.Replace(input, rule.Replacement);
+            }
+        }
+        catch
+        {
+            // Ignore exceptions; return original input
+        }
+
+        return input;
+    }
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/TokenRuleProvider.cs

@@ -0,0 +1,25 @@
+// 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.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal sealed partial class TokenRuleProvider : ISanitizationRuleProvider
+{
+    public IEnumerable<SanitizationRule> GetRules()
+    {
+        yield return new(JwtRx(), "[JWT_REDACTED]", "JSON Web Tokens (JWT)");
+        yield return new(TokenRx(), "[TOKEN_REDACTED]", "Potential API keys/tokens");
+    }
+
+    [GeneratedRegex(@"\beyJ[A-Za-z0-9_-]{10,}\.[A-Za-z0-9_-]{10,}\.[A-Za-z0-9_-]{10,}\b",
+        SanitizerDefaults.DefaultOptions, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex JwtRx();
+
+    [GeneratedRegex(@"\b[A-Za-z0-9]{32,128}\b",
+        SanitizerDefaults.DefaultOptions, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex TokenRx();
+}

src/modules/cmdpal/Core/Microsoft.CmdPal.Core.Common/Services/Sanitizer/UrlRuleProvider.cs

@@ -0,0 +1,20 @@
+// 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.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+internal sealed partial class UrlRuleProvider : ISanitizationRuleProvider
+{
+    public IEnumerable<SanitizationRule> GetRules()
+    {
+        yield return new(UrlRx(), "[URL_REDACTED]", "URLs");
+    }
+
+    [GeneratedRegex(@"\b(?:https?|ftp|ftps|file|jdbc|ldap|mailto)://[^\s<>""'{}\[\]\\^`|]+",
+        SanitizerDefaults.DefaultOptions, SanitizerDefaults.DefaultMatchTimeoutMs)]
+    private static partial Regex UrlRx();
+}

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

@@ -0,0 +1,136 @@
+// 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.Collections.Concurrent;
+using Microsoft.CmdPal.Core.Common;
+using Microsoft.CmdPal.Core.Common.Helpers;
+
+namespace Microsoft.CmdPal.Core.ViewModels;
+
+internal static class BatchUpdateManager
+{
+    private const int ExpectedBatchSize = 32;
+
+    // 30 ms chosen empirically to balance responsiveness and batching:
+    // - Keeps perceived latency low (< ~50 ms) for user-visible updates.
+    // - Still allows multiple COM/background events to be coalesced into a single batch.
+    private static readonly TimeSpan BatchDelay = TimeSpan.FromMilliseconds(30);
+    private static readonly ConcurrentQueue<IBatchUpdateTarget> DirtyQueue = [];
+    private static readonly Timer Timer = new(static _ => Flush(), null, Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan);
+
+    private static InterlockedBoolean _isFlushScheduled;
+
+    /// <summary>
+    /// Enqueue a target for batched processing. Safe to call from any thread (including COM callbacks).
+    /// </summary>
+    public static void Queue(IBatchUpdateTarget target)
+    {
+        if (!target.TryMarkBatchQueued())
+        {
+            return; // already queued in current batch window
+        }
+
+        DirtyQueue.Enqueue(target);
+        TryScheduleFlush();
+    }
+
+    private static void TryScheduleFlush()
+    {
+        if (!_isFlushScheduled.Set())
+        {
+            return;
+        }
+
+        if (DirtyQueue.IsEmpty)
+        {
+            _isFlushScheduled.Clear();
+
+            if (DirtyQueue.IsEmpty)
+            {
+                return;
+            }
+
+            if (!_isFlushScheduled.Set())
+            {
+                return;
+            }
+        }
+
+        try
+        {
+            Timer.Change(BatchDelay, Timeout.InfiniteTimeSpan);
+        }
+        catch (Exception ex)
+        {
+            _isFlushScheduled.Clear();
+            CoreLogger.LogError("Failed to arm batch timer.", ex);
+        }
+    }
+
+    private static void Flush()
+    {
+        try
+        {
+            var drained = new List<IBatchUpdateTarget>(ExpectedBatchSize);
+            while (DirtyQueue.TryDequeue(out var item))
+            {
+                drained.Add(item);
+            }
+
+            if (drained.Count == 0)
+            {
+                return;
+            }
+
+            // LOAD BEARING:
+            // ApplyPendingUpdates must run on a background thread.
+            // The VM itself is responsible for marshaling UI notifications to its _uiScheduler.
+            ApplyBatch(drained);
+        }
+        catch (Exception ex)
+        {
+            // Don't kill the timer thread.
+            CoreLogger.LogError("Batch flush failed.", ex);
+        }
+        finally
+        {
+            _isFlushScheduled.Clear();
+            TryScheduleFlush();
+        }
+    }
+
+    private static void ApplyBatch(List<IBatchUpdateTarget> items)
+    {
+        // Runs on the Timer callback thread (ThreadPool). That's fine: background work only.
+        foreach (var item in items)
+        {
+            // Allow re-queueing immediately if more COM events arrive during apply.
+            item.ClearBatchQueued();
+
+            try
+            {
+                item.ApplyPendingUpdates();
+            }
+            catch (Exception ex)
+            {
+                CoreLogger.LogError("Failed to apply pending updates for a batched target.", ex);
+            }
+        }
+    }
+}
+
+internal interface IBatchUpdateTarget
+{
+    /// <summary>UI scheduler (used by targets internally for UI marshaling). Kept here for diagnostics / consistency.</summary>
+    TaskScheduler UIScheduler { get; }
+
+    /// <summary>Apply any coalesced updates. Must be safe to call on a background thread.</summary>
+    void ApplyPendingUpdates();
+
+    /// <summary>De-dupe gate: returns true only for the first enqueue until cleared.</summary>
+    bool TryMarkBatchQueued();
+
+    /// <summary>Clear the de-dupe gate so the item can be queued again.</summary>
+    void ClearBatchQueued();
+}

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

@@ -2,36 +2,99 @@
 // 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.Buffers;
+using System.Collections.Concurrent;
+using System.ComponentModel;
+using System.Runtime.CompilerServices;
 using CommunityToolkit.Mvvm.ComponentModel;
 using Microsoft.CmdPal.Core.Common;
+using Microsoft.CmdPal.Core.Common.Helpers;
 
 namespace Microsoft.CmdPal.Core.ViewModels;
 
-public abstract partial class ExtensionObjectViewModel : ObservableObject
+public abstract partial class ExtensionObjectViewModel : ObservableObject, IBatchUpdateTarget, IBackgroundPropertyChangedNotification
 {
-    public WeakReference<IPageContext> PageContext { get; set; }
+    private const int InitialPropertyBatchingBufferSize = 16;
 
-    internal ExtensionObjectViewModel(IPageContext? context)
-    {
-        var realContext = context ?? (this is IPageContext c ? c : throw new ArgumentException("You need to pass in an IErrorContext"));
-        PageContext = new(realContext);
-    }
+    // Raised on the background thread before UI notifications. It's raised on the background thread to prevent
+    // blocking the COM proxy.
+    public event PropertyChangedEventHandler? PropertyChangedBackground;
 
-    internal ExtensionObjectViewModel(WeakReference<IPageContext> context)
-    {
-        PageContext = context;
-    }
+    private readonly ConcurrentQueue<string> _pendingProps = [];
 
-    public async virtual Task InitializePropertiesAsync()
+    private readonly TaskScheduler _uiScheduler;
+
+    private InterlockedBoolean _batchQueued;
+
+    public WeakReference<IPageContext> PageContext { get; private set; } = null!;
+
+    TaskScheduler IBatchUpdateTarget.UIScheduler => _uiScheduler;
+
+    void IBatchUpdateTarget.ApplyPendingUpdates() => ApplyPendingUpdates();
+
+    bool IBatchUpdateTarget.TryMarkBatchQueued() => _batchQueued.Set();
+
+    void IBatchUpdateTarget.ClearBatchQueued() => _batchQueued.Clear();
+
+    private protected ExtensionObjectViewModel(TaskScheduler scheduler)
     {
-        var t = new Task(() =>
+        if (this is not IPageContext)
         {
-            SafeInitializePropertiesSynchronous();
-        });
-        t.Start();
-        await t;
+            throw new InvalidOperationException($"Constructor overload without IPageContext can only be used when the derived class implements IPageContext. Type: {GetType().FullName}");
+        }
+
+        _uiScheduler = scheduler ?? throw new ArgumentNullException(nameof(scheduler));
+
+        // Defer PageContext assignment - derived constructor MUST call InitializePageContext()
+        // or we set it lazily on first access
     }
 
+    private protected ExtensionObjectViewModel(IPageContext context)
+    {
+        ArgumentNullException.ThrowIfNull(context);
+
+        PageContext = new WeakReference<IPageContext>(context);
+        _uiScheduler = context.Scheduler;
+
+        LogIfDefaultScheduler();
+    }
+
+    private protected ExtensionObjectViewModel(WeakReference<IPageContext> contextRef)
+    {
+        ArgumentNullException.ThrowIfNull(contextRef);
+
+        if (!contextRef.TryGetTarget(out var context))
+        {
+            throw new ArgumentException("IPageContext must be alive when creating view models.", nameof(contextRef));
+        }
+
+        PageContext = contextRef;
+        _uiScheduler = context.Scheduler;
+
+        LogIfDefaultScheduler();
+    }
+
+    protected void InitializeSelfAsPageContext()
+    {
+        if (this is not IPageContext self)
+        {
+            throw new InvalidOperationException("This method can only be called when the class implements IPageContext.");
+        }
+
+        PageContext = new WeakReference<IPageContext>(self);
+    }
+
+    private void LogIfDefaultScheduler()
+    {
+        if (_uiScheduler == TaskScheduler.Default)
+        {
+            CoreLogger.LogDebug($"ExtensionObjectViewModel created with TaskScheduler.Default. Type: {GetType().FullName}");
+        }
+    }
+
+    public virtual Task InitializePropertiesAsync()
+        => Task.Run(SafeInitializePropertiesSynchronous);
+
     public void SafeInitializePropertiesSynchronous()
     {
         try
@@ -46,49 +109,151 @@ public abstract partial class ExtensionObjectViewModel : ObservableObject
 
     public abstract void InitializeProperties();
 
-    protected void UpdateProperty(string propertyName)
-    {
-        DoOnUiThread(() => OnPropertyChanged(propertyName));
-    }
+    protected void UpdateProperty(string propertyName) => MarkPropertyDirty(propertyName);
 
     protected void UpdateProperty(string propertyName1, string propertyName2)
     {
-        DoOnUiThread(() =>
-        {
-            OnPropertyChanged(propertyName1);
-            OnPropertyChanged(propertyName2);
-        });
-    }
-
-    protected void UpdateProperty(string propertyName1, string propertyName2, string propertyName3)
-    {
-        DoOnUiThread(() =>
-        {
-            OnPropertyChanged(propertyName1);
-            OnPropertyChanged(propertyName2);
-            OnPropertyChanged(propertyName3);
-        });
+        MarkPropertyDirty(propertyName1);
+        MarkPropertyDirty(propertyName2);
     }
 
     protected void UpdateProperty(params string[] propertyNames)
     {
-        DoOnUiThread(() =>
+        foreach (var p in propertyNames)
         {
-            foreach (var propertyName in propertyNames)
-            {
-                OnPropertyChanged(propertyName);
-            }
-        });
+            MarkPropertyDirty(p);
+        }
     }
 
+    internal void MarkPropertyDirty(string? propertyName)
+    {
+        if (string.IsNullOrEmpty(propertyName))
+        {
+            return;
+        }
+
+        // We should re-consider if this worth deduping
+        _pendingProps.Enqueue(propertyName);
+        BatchUpdateManager.Queue(this);
+    }
+
+    public void ApplyPendingUpdates()
+    {
+        ((IBatchUpdateTarget)this).ClearBatchQueued();
+
+        var buffer = ArrayPool<string>.Shared.Rent(InitialPropertyBatchingBufferSize);
+        var count = 0;
+        var transferred = false;
+
+        try
+        {
+            while (_pendingProps.TryDequeue(out var name))
+            {
+                if (count == buffer.Length)
+                {
+                    var bigger = ArrayPool<string>.Shared.Rent(buffer.Length * 2);
+                    Array.Copy(buffer, bigger, buffer.Length);
+                    ArrayPool<string>.Shared.Return(buffer, clearArray: true);
+                    buffer = bigger;
+                }
+
+                buffer[count++] = name;
+            }
+
+            if (count == 0)
+            {
+                return;
+            }
+
+            // 1) Background subscribers (must be raised before UI notifications).
+            var propertyChangedEventHandler = PropertyChangedBackground;
+            if (propertyChangedEventHandler is not null)
+            {
+                RaiseBackground(propertyChangedEventHandler, this, buffer, count);
+            }
+
+            // 2) UI-facing PropertyChanged: ALWAYS marshal to UI scheduler.
+            // Hand-off pooled buffer to UI task (UI task returns it).
+            //
+            // It would be lovely to do nothing if no one is actually listening on PropertyChanged,
+            // but ObservableObject doesn't expose that information.
+            _ = Task.Factory.StartNew(
+                static state =>
+                {
+                    var p = (UiBatch)state!;
+                    try
+                    {
+                        p.Owner.RaiseUi(p.Names, p.Count);
+                    }
+                    catch (Exception ex)
+                    {
+                        CoreLogger.LogError("Failed to raise property change notifications on UI thread.", ex);
+                    }
+                    finally
+                    {
+                        ArrayPool<string>.Shared.Return(p.Names, clearArray: true);
+                    }
+                },
+                new UiBatch(this, buffer, count),
+                CancellationToken.None,
+                TaskCreationOptions.DenyChildAttach,
+                _uiScheduler);
+
+            transferred = true;
+        }
+        catch (Exception ex)
+        {
+            CoreLogger.LogError("Failed to apply pending property updates.", ex);
+        }
+        finally
+        {
+            if (!transferred)
+            {
+                ArrayPool<string>.Shared.Return(buffer, clearArray: true);
+            }
+        }
+    }
+
+    private void RaiseUi(string[] names, int count)
+    {
+        for (var i = 0; i < count; i++)
+        {
+            OnPropertyChanged(Args(names[i]));
+        }
+    }
+
+    private static void RaiseBackground(PropertyChangedEventHandler handlers, object sender, string[] names, int count)
+    {
+        try
+        {
+            for (var i = 0; i < count; i++)
+            {
+                handlers(sender, Args(names[i]));
+            }
+        }
+        catch (Exception ex)
+        {
+            CoreLogger.LogError("Failed to raise PropertyChangedBackground notifications.", ex);
+        }
+    }
+
+    private sealed record UiBatch(ExtensionObjectViewModel Owner, string[] Names, int Count);
+
     protected void ShowException(Exception ex, string? extensionHint = null)
     {
         if (PageContext.TryGetTarget(out var pageContext))
         {
             pageContext.ShowException(ex, extensionHint);
         }
+        else
+        {
+            CoreLogger.LogError("Failed to show exception because PageContext is no longer available.", ex);
+        }
     }
 
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private static PropertyChangedEventArgs Args(string name) => new(name);
+
     protected void DoOnUiThread(Action action)
     {
         if (PageContext.TryGetTarget(out var pageContext))

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

@@ -0,0 +1,19 @@
+// 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.ComponentModel;
+
+namespace Microsoft.CmdPal.Core.ViewModels;
+
+/// <summary>
+/// Provides a notification mechanism for property changes that fires
+/// synchronously on the calling thread.
+/// </summary>
+public interface IBackgroundPropertyChangedNotification
+{
+    /// <summary>
+    /// Occurs when the value of a property changes.
+    /// </summary>
+    event PropertyChangedEventHandler? PropertyChangedBackground;
+}

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

@@ -77,11 +77,11 @@ public partial class PageViewModel : ExtensionObjectViewModel, IPageContext
     public IconInfoViewModel Icon { get; protected set; }
 
     public PageViewModel(IPage? model, TaskScheduler scheduler, AppExtensionHost extensionHost)
-        : base((IPageContext?)null)
+        : base(scheduler)
     {
+        InitializeSelfAsPageContext();
         _pageModel = new(model);
         Scheduler = scheduler;
-        PageContext = new(this);
         ExtensionHost = extensionHost;
         Icon = new(null);
 

src/modules/cmdpal/CoreCommonProps.props

@@ -43,4 +43,10 @@
     </EmbeddedResource>
   </ItemGroup>
 
+  <ItemGroup>
+    <AssemblyAttribute Include="System.Runtime.CompilerServices.InternalsVisibleToAttribute">
+       <_Parameter1>$(AssemblyName).UnitTests</_Parameter1>
+    </AssemblyAttribute>
+  </ItemGroup>
+
 </Project>

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/CommandProviderWrapper.cs

@@ -6,6 +6,7 @@ using ManagedCommon;
 using Microsoft.CmdPal.Core.Common.Services;
 using Microsoft.CmdPal.Core.ViewModels;
 using Microsoft.CmdPal.Core.ViewModels.Models;
+using Microsoft.CmdPal.UI.ViewModels.Services;
 using Microsoft.CommandPalette.Extensions;
 using Microsoft.Extensions.DependencyInjection;
 
@@ -23,6 +24,8 @@ public sealed class CommandProviderWrapper
 
     private readonly TaskScheduler _taskScheduler;
 
+    private readonly ICommandProviderCache? _commandProviderCache;
+
     public TopLevelViewModel[] TopLevelItems { get; private set; } = [];
 
     public TopLevelViewModel[] FallbackItems { get; private set; } = [];
@@ -43,13 +46,7 @@ public sealed class CommandProviderWrapper
 
     public bool IsActive { get; private set; }
 
-    public string ProviderId
-    {
-        get
-        {
-            return string.IsNullOrEmpty(Extension?.ExtensionUniqueId) ? Id : Extension.ExtensionUniqueId;
-        }
-    }
+    public string ProviderId => string.IsNullOrEmpty(Extension?.ExtensionUniqueId) ? Id : Extension.ExtensionUniqueId;
 
     public CommandProviderWrapper(ICommandProvider provider, TaskScheduler mainThread)
     {
@@ -77,9 +74,11 @@ public sealed class CommandProviderWrapper
         Logger.LogDebug($"Initialized command provider {ProviderId}");
     }
 
-    public CommandProviderWrapper(IExtensionWrapper extension, TaskScheduler mainThread)
+    public CommandProviderWrapper(IExtensionWrapper extension, TaskScheduler mainThread, ICommandProviderCache commandProviderCache)
     {
         _taskScheduler = mainThread;
+        _commandProviderCache = commandProviderCache;
+
         Extension = extension;
         ExtensionHost = new CommandPaletteHost(extension);
         if (!Extension.IsRunning())
@@ -128,30 +127,31 @@ public sealed class CommandProviderWrapper
         if (!isValid)
         {
             IsActive = false;
+            RecallFromCache();
             return;
         }
 
         var settings = serviceProvider.GetService<SettingsModel>()!;
 
-        IsActive = GetProviderSettings(settings).IsEnabled;
+        var providerSettings = GetProviderSettings(settings);
+        IsActive = providerSettings.IsEnabled;
         if (!IsActive)
         {
+            RecallFromCache();
             return;
         }
 
-        ICommandItem[]? commands = null;
-        IFallbackCommandItem[]? fallbacks = null;
-
+        var displayInfoInitialized = false;
         try
         {
             var model = _commandProvider.Unsafe!;
 
-            Task<ICommandItem[]> t = new(model.TopLevelCommands);
-            t.Start();
-            commands = await t.ConfigureAwait(false);
+            Task<ICommandItem[]> loadTopLevelCommandsTask = new(model.TopLevelCommands);
+            loadTopLevelCommandsTask.Start();
+            var commands = await loadTopLevelCommandsTask.ConfigureAwait(false);
 
             // On a BG thread here
-            fallbacks = model.FallbackCommands();
+            var fallbacks = model.FallbackCommands();
 
             if (model is ICommandProvider2 two)
             {
@@ -162,6 +162,13 @@ public sealed class CommandProviderWrapper
             DisplayName = model.DisplayName;
             Icon = new(model.Icon);
             Icon.InitializeProperties();
+            displayInfoInitialized = true;
+
+            // Update cached display name
+            if (_commandProviderCache is not null && Extension?.ExtensionUniqueId is not null)
+            {
+                _commandProviderCache.Memorize(Extension.ExtensionUniqueId, new CommandProviderCacheItem(model.DisplayName));
+            }
 
             // Note: explicitly not InitializeProperties()ing the settings here. If
             // we do that, then we'd regress GH #38321
@@ -177,6 +184,25 @@ public sealed class CommandProviderWrapper
             Logger.LogError("Failed to load commands from extension");
             Logger.LogError($"Extension was {Extension!.PackageFamilyName}");
             Logger.LogError(e.ToString());
+
+            if (!displayInfoInitialized)
+            {
+                RecallFromCache();
+            }
+        }
+    }
+
+    private void RecallFromCache()
+    {
+        var cached = _commandProviderCache?.Recall(ProviderId);
+        if (cached is not null)
+        {
+            DisplayName = cached.DisplayName;
+        }
+
+        if (string.IsNullOrWhiteSpace(DisplayName))
+        {
+            DisplayName = Extension?.PackageDisplayName ?? Extension?.PackageFamilyName ?? ProviderId;
         }
     }
 
@@ -185,7 +211,7 @@ public sealed class CommandProviderWrapper
         var settings = serviceProvider.GetService<SettingsModel>()!;
         var providerSettings = GetProviderSettings(settings);
 
-        Func<ICommandItem?, bool, TopLevelViewModel> makeAndAdd = (ICommandItem? i, bool fallback) =>
+        var makeAndAdd = (ICommandItem? i, bool fallback) =>
         {
             CommandItemViewModel commandItemViewModel = new(new(i), pageContext);
             TopLevelViewModel topLevelViewModel = new(commandItemViewModel, fallback, ExtensionHost, ProviderId, settings, providerSettings, serviceProvider, i);

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Commands/OpenSettingsCommand.cs

@@ -19,7 +19,7 @@ public partial class OpenSettingsCommand : InvokableCommand
 
     public override ICommandResult Invoke()
     {
-        WeakReferenceMessenger.Default.Send<OpenSettingsMessage>();
+        WeakReferenceMessenger.Default.Send(new OpenSettingsMessage());
         return CommandResult.KeepOpen();
     }
 }

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Messages/OpenSettingsMessage.cs

@@ -4,6 +4,4 @@
 
 namespace Microsoft.CmdPal.UI.Messages;
 
-public record OpenSettingsMessage()
-{
-}
+public record OpenSettingsMessage(string SettingsPageTag = "");

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/ProviderSettingsViewModel.cs

@@ -14,11 +14,13 @@ namespace Microsoft.CmdPal.UI.ViewModels;
 
 public partial class ProviderSettingsViewModel : ObservableObject
 {
+    private static readonly IconInfoViewModel EmptyIcon = new(null);
+
     private readonly CommandProviderWrapper _provider;
     private readonly ProviderSettings _providerSettings;
     private readonly SettingsModel _settings;
-
     private readonly Lock _initializeSettingsLock = new();
+
     private Task? _initializeSettingsTask;
 
     public ProviderSettingsViewModel(
@@ -43,7 +45,7 @@ public partial class ProviderSettingsViewModel : ObservableObject
         HasFallbackCommands ?
             $"{ExtensionName}, {TopLevelCommands.Count} commands, {_provider.FallbackItems?.Length} fallback commands" :
             $"{ExtensionName}, {TopLevelCommands.Count} commands" :
-        Resources.builtin_disabled_extension;
+        $"{ExtensionName}, {Resources.builtin_disabled_extension}";
 
     [MemberNotNullWhen(true, nameof(Extension))]
     public bool IsFromExtension => _provider.Extension is not null;
@@ -52,7 +54,7 @@ public partial class ProviderSettingsViewModel : ObservableObject
 
     public string ExtensionVersion => IsFromExtension ? $"{Extension.Version.Major}.{Extension.Version.Minor}.{Extension.Version.Build}.{Extension.Version.Revision}" : string.Empty;
 
-    public IconInfoViewModel Icon => _provider.Icon;
+    public IconInfoViewModel Icon => IsEnabled ? _provider.Icon : EmptyIcon;
 
     [ObservableProperty]
     public partial bool LoadingSettings { get; set; }
@@ -69,6 +71,7 @@ public partial class ProviderSettingsViewModel : ObservableObject
                 WeakReferenceMessenger.Default.Send<ReloadCommandsMessage>(new());
                 OnPropertyChanged(nameof(IsEnabled));
                 OnPropertyChanged(nameof(ExtensionSubtext));
+                OnPropertyChanged(nameof(Icon));
             }
 
             if (value == true)

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Services/CommandProviderCacheContainer.cs

@@ -0,0 +1,10 @@
+// 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.UI.ViewModels.Services;
+
+internal sealed class CommandProviderCacheContainer
+{
+    public Dictionary<string, CommandProviderCacheItem> Cache { get; init; } = new(StringComparer.Ordinal);
+}

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Services/CommandProviderCacheItem.cs

@@ -0,0 +1,7 @@
+// 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.UI.ViewModels.Services;
+
+public record CommandProviderCacheItem(string DisplayName);

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Services/CommandProviderCacheSerializationContext.cs

@@ -0,0 +1,13 @@
+// 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.Text.Json.Serialization;
+
+namespace Microsoft.CmdPal.UI.ViewModels.Services;
+
+[JsonSerializable(typeof(CommandProviderCacheItem))]
+[JsonSerializable(typeof(Dictionary<string, CommandProviderCacheItem>))]
+[JsonSerializable(typeof(CommandProviderCacheContainer))]
+[JsonSourceGenerationOptions(WriteIndented = true, PropertyNameCaseInsensitive = false)]
+internal sealed partial class CommandProviderCacheSerializationContext : JsonSerializerContext;

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Services/DefaultCommandProviderCache.cs

@@ -0,0 +1,127 @@
+// 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.Text.Json;
+using ManagedCommon;
+using Microsoft.CmdPal.Core.Common.Helpers;
+using Microsoft.CommandPalette.Extensions.Toolkit;
+
+namespace Microsoft.CmdPal.UI.ViewModels.Services;
+
+public sealed partial class DefaultCommandProviderCache : ICommandProviderCache, IDisposable
+{
+    private const string CacheFileName = "commandProviderCache.json";
+
+    private readonly Dictionary<string, CommandProviderCacheItem> _cache = new(StringComparer.Ordinal);
+
+    private readonly Lock _sync = new();
+
+    private readonly SupersedingAsyncGate _saveGate;
+
+    public DefaultCommandProviderCache()
+    {
+        _saveGate = new SupersedingAsyncGate(async _ => await TrySaveAsync().ConfigureAwait(false));
+        TryLoad();
+    }
+
+    public void Memorize(string providerId, CommandProviderCacheItem item)
+    {
+        ArgumentNullException.ThrowIfNull(providerId);
+
+        lock (_sync)
+        {
+            _cache[providerId] = item;
+        }
+
+        _ = _saveGate.ExecuteAsync();
+    }
+
+    public CommandProviderCacheItem? Recall(string providerId)
+    {
+        ArgumentNullException.ThrowIfNull(providerId);
+
+        lock (_sync)
+        {
+            _cache.TryGetValue(providerId, out var item);
+            return item;
+        }
+    }
+
+    private static string GetCacheFilePath()
+    {
+        var directory = Utilities.BaseSettingsPath("Microsoft.CmdPal");
+        Directory.CreateDirectory(directory);
+        return Path.Combine(directory, CacheFileName);
+    }
+
+    private void TryLoad()
+    {
+        try
+        {
+            var path = GetCacheFilePath();
+            if (!File.Exists(path))
+            {
+                return;
+            }
+
+            var json = File.ReadAllText(path);
+            if (string.IsNullOrWhiteSpace(json))
+            {
+                return;
+            }
+
+            var loaded = JsonSerializer.Deserialize(
+                json,
+                CommandProviderCacheSerializationContext.Default.CommandProviderCacheContainer!);
+            if (loaded?.Cache is null)
+            {
+                return;
+            }
+
+            _cache.Clear();
+            foreach (var kvp in loaded.Cache)
+            {
+                if (!string.IsNullOrEmpty(kvp.Key) && kvp.Value is not null)
+                {
+                    _cache[kvp.Key] = kvp.Value;
+                }
+            }
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError("Failed to load command provider cache: ", ex);
+        }
+    }
+
+    private async Task TrySaveAsync()
+    {
+        try
+        {
+            Dictionary<string, CommandProviderCacheItem> snapshot;
+            lock (_sync)
+            {
+                snapshot = new Dictionary<string, CommandProviderCacheItem>(_cache, StringComparer.Ordinal);
+            }
+
+            var container = new CommandProviderCacheContainer
+            {
+                Cache = snapshot,
+            };
+
+            var path = GetCacheFilePath();
+            var json = JsonSerializer.Serialize(container, CommandProviderCacheSerializationContext.Default.CommandProviderCacheContainer!);
+            await File.WriteAllTextAsync(path, json).ConfigureAwait(false);
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError("Failed to save command provider cache: ", ex);
+        }
+    }
+
+    public void Dispose()
+    {
+        _saveGate.Dispose();
+        GC.SuppressFinalize(this);
+    }
+}

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/Services/ICommandProviderCache.cs

@@ -0,0 +1,12 @@
+// 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.UI.ViewModels.Services;
+
+public interface ICommandProviderCache
+{
+    void Memorize(string providerId, CommandProviderCacheItem item);
+
+    CommandProviderCacheItem? Recall(string providerId);
+}

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/TopLevelCommandManager.cs

@@ -13,6 +13,7 @@ using Microsoft.CmdPal.Core.Common.Helpers;
 using Microsoft.CmdPal.Core.Common.Services;
 using Microsoft.CmdPal.Core.ViewModels;
 using Microsoft.CmdPal.UI.ViewModels.Messages;
+using Microsoft.CmdPal.UI.ViewModels.Services;
 using Microsoft.CommandPalette.Extensions;
 using Microsoft.CommandPalette.Extensions.Toolkit;
 using Microsoft.Extensions.DependencyInjection;
@@ -25,6 +26,7 @@ public partial class TopLevelCommandManager : ObservableObject,
     IDisposable
 {
     private readonly IServiceProvider _serviceProvider;
+    private readonly ICommandProviderCache _commandProviderCache;
     private readonly TaskScheduler _taskScheduler;
 
     private readonly List<CommandProviderWrapper> _builtInCommands = [];
@@ -34,9 +36,10 @@ public partial class TopLevelCommandManager : ObservableObject,
 
     TaskScheduler IPageContext.Scheduler => _taskScheduler;
 
-    public TopLevelCommandManager(IServiceProvider serviceProvider)
+    public TopLevelCommandManager(IServiceProvider serviceProvider, ICommandProviderCache commandProviderCache)
     {
         _serviceProvider = serviceProvider;
+        _commandProviderCache = commandProviderCache;
         _taskScheduler = _serviceProvider.GetService<TaskScheduler>()!;
         WeakReferenceMessenger.Default.Register<ReloadCommandsMessage>(this);
         _reloadCommandsGate = new(ReloadAllCommandsAsyncCore);
@@ -319,7 +322,7 @@ public partial class TopLevelCommandManager : ObservableObject,
         try
         {
             await extension.StartExtensionAsync().WaitAsync(TimeSpan.FromSeconds(10));
-            return new CommandProviderWrapper(extension, _taskScheduler);
+            return new CommandProviderWrapper(extension, _taskScheduler, _commandProviderCache);
         }
         catch (Exception ex)
         {

src/modules/cmdpal/Microsoft.CmdPal.UI.ViewModels/TopLevelViewModel.cs

@@ -199,7 +199,7 @@ public sealed partial class TopLevelViewModel : ObservableObject, IListItem, IEx
             _fallbackId = fallback.Id;
         }
 
-        item.PropertyChanged += Item_PropertyChanged;
+        item.PropertyChangedBackground += Item_PropertyChanged;
 
         // UpdateAlias();
         // UpdateHotkey();

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

@@ -41,7 +41,7 @@ namespace Microsoft.CmdPal.UI;
 /// <summary>
 /// Provides application-specific behavior to supplement the default Application class.
 /// </summary>
-public partial class App : Application
+public partial class App : Application, IDisposable
 {
     private readonly GlobalErrorHandler _globalErrorHandler = new();
 
@@ -67,7 +67,7 @@ public partial class App : Application
     public App()
     {
 #if !CMDPAL_DISABLE_GLOBAL_ERROR_HANDLER
-        _globalErrorHandler.Register(this);
+        _globalErrorHandler.Register(this, GlobalErrorHandler.Options.Default);
 #endif
 
         Services = ConfigureServices();
@@ -178,6 +178,7 @@ public partial class App : Application
         services.AddSingleton(state);
 
         // Services
+        services.AddSingleton<ICommandProviderCache, DefaultCommandProviderCache>();
         services.AddSingleton<TopLevelCommandManager>();
         services.AddSingleton<AliasManager>();
         services.AddSingleton<HotkeyManager>();
@@ -203,4 +204,11 @@ public partial class App : Application
         services.AddSingleton<ShellViewModel>();
         services.AddSingleton<IPageViewModelFactoryService, CommandPalettePageViewModelFactory>();
     }
+
+    public void Dispose()
+    {
+        _globalErrorHandler.Dispose();
+        EtwTrace.Dispose();
+        GC.SuppressFinalize(this);
+    }
 }

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

@@ -128,7 +128,7 @@ public sealed partial class CommandBar : UserControl,
 
     private void SettingsIcon_Clicked(object sender, RoutedEventArgs e)
     {
-        WeakReferenceMessenger.Default.Send<OpenSettingsMessage>();
+        WeakReferenceMessenger.Default.Send(new OpenSettingsMessage());
     }
 
     private void MoreCommandsButton_Clicked(object sender, RoutedEventArgs e)

src/modules/cmdpal/Microsoft.CmdPal.UI/Controls/DevRibbon.xaml

@@ -203,6 +203,12 @@
 
                                     </Grid>
                                 </Border>
+
+                                <!--  More section  -->
+                                <TextBlock Style="{ThemeResource SettingsSectionHeaderTextBlockStyle}" Text="More" />
+                                <Border>
+                                    <Button Command="{x:Bind ViewModel.OpenInternalToolsCommand}" Content="Open internal tools" />
+                                </Border>
                             </StackPanel>
 
                             <!--  Footer  -->

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

@@ -3,7 +3,7 @@
 // See the LICENSE file in the project root for more information.
 
 using ManagedCommon;
-using Microsoft.CmdPal.Core.Common.Helpers;
+using Microsoft.CmdPal.Core.Common.Services.Reports;
 using Windows.Win32;
 using Windows.Win32.Foundation;
 using Windows.Win32.UI.WindowsAndMessaging;
@@ -15,14 +15,22 @@ namespace Microsoft.CmdPal.UI.Helpers;
 /// <summary>
 /// Global error handler for Command Palette.
 /// </summary>
-internal sealed partial class GlobalErrorHandler
+internal sealed partial class GlobalErrorHandler : IDisposable
 {
+    private readonly ErrorReportBuilder _errorReportBuilder = new();
+    private Options? _options;
+    private App? _app;
+
     // GlobalErrorHandler is designed to be self-contained; it can be registered and invoked before a service provider is available.
-    internal void Register(App app)
+    internal void Register(App app, Options options)
     {
         ArgumentNullException.ThrowIfNull(app);
+        ArgumentNullException.ThrowIfNull(options);
 
-        app.UnhandledException += App_UnhandledException;
+        _options = options;
+
+        _app = app;
+        _app.UnhandledException += App_UnhandledException;
         TaskScheduler.UnobservedTaskException += TaskScheduler_UnobservedTaskException;
         AppDomain.CurrentDomain.UnhandledException += CurrentDomain_UnhandledException;
     }
@@ -54,21 +62,15 @@ internal sealed partial class GlobalErrorHandler
         HandleException(e.Exception, Context.UnobservedTaskException);
     }
 
-    private static void HandleException(Exception ex, Context context)
+    private void HandleException(Exception ex, Context context)
     {
         Logger.LogError($"Unhandled exception detected ({context})", ex);
 
         if (context == Context.MainThreadException)
         {
-            var error = DiagnosticsHelper.BuildExceptionMessage(ex, null);
-            var report = $"""
-                          This is an error report generated by Windows Command Palette.
-                          If you are seeing this message, it means the application has encountered an unexpected issue.
-                          You can help us fix it by filing a report at https://aka.ms/powerToysReportBug.
-                          {error}
-                          """;
+            var report = _errorReportBuilder.BuildReport(ex, context.ToString(), _options?.RedactPii ?? true);
 
-            StoreReport(report, storeOnDesktop: false);
+            StoreReport(report, storeOnDesktop: _options?.StoreReportOnUserDesktop == true);
 
             string message;
             string caption;
@@ -138,6 +140,13 @@ internal sealed partial class GlobalErrorHandler
         }
     }
 
+    public void Dispose()
+    {
+        _app?.UnhandledException -= App_UnhandledException;
+        TaskScheduler.UnobservedTaskException -= TaskScheduler_UnobservedTaskException;
+        AppDomain.CurrentDomain.UnhandledException -= CurrentDomain_UnhandledException;
+    }
+
     private enum Context
     {
         Unknown = 0,
@@ -146,4 +155,26 @@ internal sealed partial class GlobalErrorHandler
         UnobservedTaskException,
         AppDomainUnhandledException,
     }
+
+    /// <summary>
+    /// Configuration options controlling how <see cref="GlobalErrorHandler"/> reacts to exceptions
+    /// (what to log, what to show to the user, and where to store reports).
+    /// </summary>
+    internal sealed record Options
+    {
+        /// <summary>
+        /// Gets the default configuration.
+        /// </summary>
+        public static Options Default { get; } = new();
+
+        /// <summary>
+        /// Gets a value indicating whether Personally Identifiable Information (PII) should be redacted in error reports.
+        /// </summary>
+        public bool RedactPii { get; init; } = true;
+
+        /// <summary>
+        /// Gets a value indicating whether to store the error report on the user's desktop in addition to the log directory.
+        /// </summary>
+        public bool StoreReportOnUserDesktop { get; init; }
+    }
 }

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

@@ -152,7 +152,7 @@ internal sealed partial class TrayIconService
                 {
                     if (wParam == PInvoke.WM_USER + 1)
                     {
-                        WeakReferenceMessenger.Default.Send<OpenSettingsMessage>();
+                        WeakReferenceMessenger.Default.Send(new OpenSettingsMessage());
                     }
                     else if (wParam == PInvoke.WM_USER + 2)
                     {

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

@@ -0,0 +1,152 @@
+// 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 Microsoft.UI;
+using Microsoft.UI.Windowing;
+using Windows.Graphics;
+using Windows.Win32;
+using Windows.Win32.Graphics.Gdi;
+using Windows.Win32.UI.HiDpi;
+
+namespace Microsoft.CmdPal.UI.Helpers;
+
+internal static class WindowPositionHelper
+{
+    private const int DefaultWidth = 800;
+    private const int DefaultHeight = 480;
+    private const int MinimumVisibleSize = 100;
+    private const int DefaultDpi = 96;
+
+    public static PointInt32? CalculateCenteredPosition(DisplayArea? displayArea, SizeInt32 windowSize, int windowDpi)
+    {
+        if (displayArea is null)
+        {
+            return null;
+        }
+
+        var workArea = displayArea.WorkArea;
+        if (workArea.Width <= 0 || workArea.Height <= 0)
+        {
+            return null;
+        }
+
+        var targetDpi = GetDpiForDisplay(displayArea);
+        var predictedSize = ScaleSize(windowSize, windowDpi, targetDpi);
+
+        // Clamp to work area
+        var width = Math.Min(predictedSize.Width, workArea.Width);
+        var height = Math.Min(predictedSize.Height, workArea.Height);
+
+        return new PointInt32(
+            workArea.X + ((workArea.Width - width) / 2),
+            workArea.Y + ((workArea.Height - height) / 2));
+    }
+
+    /// <summary>
+    /// Adjusts a saved window rect to ensure it's visible on the nearest display,
+    /// accounting for DPI changes and work area differences.
+    /// </summary>
+    ///
+    public static RectInt32 AdjustRectForVisibility(RectInt32 savedRect, SizeInt32 savedScreenSize, int savedDpi)
+    {
+        var displayArea = DisplayArea.GetFromRect(savedRect, DisplayAreaFallback.Nearest);
+        if (displayArea is null)
+        {
+            return savedRect;
+        }
+
+        var workArea = displayArea.WorkArea;
+        if (workArea.Width <= 0 || workArea.Height <= 0)
+        {
+            return savedRect;
+        }
+
+        var targetDpi = GetDpiForDisplay(displayArea);
+        if (savedDpi <= 0)
+        {
+            savedDpi = targetDpi;
+        }
+
+        var hasInvalidSize = savedRect.Width <= 0 || savedRect.Height <= 0;
+        if (hasInvalidSize)
+        {
+            savedRect = savedRect with { Width = DefaultWidth, Height = DefaultHeight };
+        }
+
+        if (targetDpi != savedDpi)
+        {
+            savedRect = ScaleRect(savedRect, savedDpi, targetDpi);
+        }
+
+        var clampedSize = ClampSize(savedRect.Width, savedRect.Height, workArea);
+
+        var shouldRecenter = hasInvalidSize ||
+                             IsOffscreen(savedRect, workArea) ||
+                             savedScreenSize.Width != workArea.Width ||
+                             savedScreenSize.Height != workArea.Height;
+
+        if (shouldRecenter)
+        {
+            return CenterRectInWorkArea(clampedSize, workArea);
+        }
+
+        return new RectInt32(savedRect.X, savedRect.Y, clampedSize.Width, clampedSize.Height);
+    }
+
+    private static int GetDpiForDisplay(DisplayArea displayArea)
+    {
+        var hMonitor = Win32Interop.GetMonitorFromDisplayId(displayArea.DisplayId);
+        if (hMonitor == IntPtr.Zero)
+        {
+            return DefaultDpi;
+        }
+
+        var hr = PInvoke.GetDpiForMonitor(
+            new HMONITOR(hMonitor),
+            MONITOR_DPI_TYPE.MDT_EFFECTIVE_DPI,
+            out var dpiX,
+            out _);
+
+        return hr.Succeeded && dpiX > 0 ? (int)dpiX : DefaultDpi;
+    }
+
+    private static SizeInt32 ScaleSize(SizeInt32 size, int fromDpi, int toDpi)
+    {
+        if (fromDpi <= 0 || toDpi <= 0 || fromDpi == toDpi)
+        {
+            return size;
+        }
+
+        var scale = (double)toDpi / fromDpi;
+        return new SizeInt32(
+            (int)Math.Round(size.Width * scale),
+            (int)Math.Round(size.Height * scale));
+    }
+
+    private static RectInt32 ScaleRect(RectInt32 rect, int fromDpi, int toDpi)
+    {
+        var scale = (double)toDpi / fromDpi;
+        return new RectInt32(
+            (int)Math.Round(rect.X * scale),
+            (int)Math.Round(rect.Y * scale),
+            (int)Math.Round(rect.Width * scale),
+            (int)Math.Round(rect.Height * scale));
+    }
+
+    private static SizeInt32 ClampSize(int width, int height, RectInt32 workArea) =>
+        new(Math.Min(width, workArea.Width), Math.Min(height, workArea.Height));
+
+    private static RectInt32 CenterRectInWorkArea(SizeInt32 size, RectInt32 workArea) =>
+        new(
+            workArea.X + ((workArea.Width - size.Width) / 2),
+            workArea.Y + ((workArea.Height - size.Height) / 2),
+            size.Width,
+            size.Height);
+
+    private static bool IsOffscreen(RectInt32 rect, RectInt32 workArea) =>
+        rect.X + MinimumVisibleSize > workArea.X + workArea.Width ||
+        rect.X + rect.Width - MinimumVisibleSize < workArea.X ||
+        rect.Y + MinimumVisibleSize > workArea.Y + workArea.Height ||
+        rect.Y + rect.Height - MinimumVisibleSize < workArea.Y;
+}

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

@@ -21,7 +21,6 @@ using Microsoft.CmdPal.UI.ViewModels.Messages;
 using Microsoft.CmdPal.UI.ViewModels.Services;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.PowerToys.Telemetry;
-using Microsoft.UI;
 using Microsoft.UI.Composition;
 using Microsoft.UI.Composition.SystemBackdrops;
 using Microsoft.UI.Input;
@@ -32,13 +31,9 @@ using Windows.ApplicationModel.Activation;
 using Windows.Foundation;
 using Windows.Graphics;
 using Windows.System;
-using Windows.UI;
-using Windows.UI.WindowManagement;
 using Windows.Win32;
 using Windows.Win32.Foundation;
 using Windows.Win32.Graphics.Dwm;
-using Windows.Win32.Graphics.Gdi;
-using Windows.Win32.UI.HiDpi;
 using Windows.Win32.UI.Input.KeyboardAndMouse;
 using Windows.Win32.UI.WindowsAndMessaging;
 using WinRT;
@@ -60,9 +55,6 @@ public sealed partial class MainWindow : WindowEx,
     IRecipient<DragCompletedMessage>,
     IDisposable
 {
-    private const int DefaultWidth = 800;
-    private const int DefaultHeight = 480;
-
     [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1310:Field names should not contain underscore", Justification = "Stylistically, window messages are WM_")]
     [System.Diagnostics.CodeAnalysis.SuppressMessage("StyleCop.CSharp.NamingRules", "SA1306:Field names should begin with lower-case letter", Justification = "Stylistically, window messages are WM_")]
     private readonly uint WM_TASKBAR_RESTART;
@@ -226,39 +218,40 @@ public sealed partial class MainWindow : WindowEx,
         PositionCentered(displayArea);
     }
 
+    private void PositionCentered(DisplayArea displayArea)
+    {
+        var position = WindowPositionHelper.CalculateCenteredPosition(
+            displayArea,
+            AppWindow.Size,
+            (int)this.GetDpiForWindow());
+
+        if (position is not null)
+        {
+            // Use Move(), not MoveAndResize(). Windows auto-resizes on DPI change via WM_DPICHANGED;
+            // the helper already accounts for this when calculating the centered position.
+            AppWindow.Move((PointInt32)position);
+        }
+    }
+
     private void RestoreWindowPosition()
     {
         var settings = App.Current.Services.GetService<SettingsModel>();
-        if (settings?.LastWindowPosition is not WindowPosition savedPosition)
+        if (settings?.LastWindowPosition is not { Width: > 0, Height: > 0 } savedPosition)
         {
             PositionCentered();
             return;
         }
 
-        if (savedPosition.Width <= 0 || savedPosition.Height <= 0)
-        {
-            PositionCentered();
-            return;
-        }
+        // MoveAndResize is safe here—we're restoring a saved state at startup,
+        // not moving a live window between displays.
+        var newRect = WindowPositionHelper.AdjustRectForVisibility(
+            savedPosition.ToPhysicalWindowRectangle(),
+            new SizeInt32(savedPosition.ScreenWidth, savedPosition.ScreenHeight),
+            savedPosition.Dpi);
 
-        var newRect = EnsureWindowIsVisible(savedPosition.ToPhysicalWindowRectangle(), new SizeInt32(savedPosition.ScreenWidth, savedPosition.ScreenHeight), savedPosition.Dpi);
         AppWindow.MoveAndResize(newRect);
     }
 
-    private void PositionCentered(DisplayArea displayArea)
-    {
-        if (displayArea is not null)
-        {
-            var centeredPosition = AppWindow.Position;
-            centeredPosition.X = (displayArea.WorkArea.Width - AppWindow.Size.Width) / 2;
-            centeredPosition.Y = (displayArea.WorkArea.Height - AppWindow.Size.Height) / 2;
-
-            centeredPosition.X += displayArea.WorkArea.X;
-            centeredPosition.Y += displayArea.WorkArea.Y;
-            AppWindow.Move(centeredPosition);
-        }
-    }
-
     private void UpdateWindowPositionInMemory()
     {
         var displayArea = DisplayArea.GetFromWindowId(AppWindow.Id, DisplayAreaFallback.Nearest) ?? DisplayArea.Primary;
@@ -352,7 +345,8 @@ public sealed partial class MainWindow : WindowEx,
 
         if (target == MonitorBehavior.ToLast)
         {
-            var newRect = EnsureWindowIsVisible(_currentWindowPosition.ToPhysicalWindowRectangle(), new SizeInt32(_currentWindowPosition.ScreenWidth, _currentWindowPosition.ScreenHeight), _currentWindowPosition.Dpi);
+            var originalScreen = new SizeInt32(_currentWindowPosition.ScreenWidth, _currentWindowPosition.ScreenHeight);
+            var newRect = WindowPositionHelper.AdjustRectForVisibility(_currentWindowPosition.ToPhysicalWindowRectangle(), originalScreen, _currentWindowPosition.Dpi);
             AppWindow.MoveAndResize(newRect);
         }
         else
@@ -382,115 +376,7 @@ public sealed partial class MainWindow : WindowEx,
         PInvoke.SetWindowPos(hwnd, HWND.HWND_TOPMOST, 0, 0, 0, 0, SET_WINDOW_POS_FLAGS.SWP_NOMOVE | SET_WINDOW_POS_FLAGS.SWP_NOSIZE);
     }
 
-    /// <summary>
-    /// Ensures that the window rectangle is visible on-screen.
-    /// </summary>
-    /// <param name="windowRect">The window rectangle in physical pixels.</param>
-    /// <param name="originalScreen">The desktop area the window was positioned on.</param>
-    /// <param name="originalDpi">The window's original DPI.</param>
-    /// <returns>
-    /// A window rectangle in physical pixels, moved to the nearest display and resized
-    /// if the DPI has changed.
-    /// </returns>
-    private static RectInt32 EnsureWindowIsVisible(RectInt32 windowRect, SizeInt32 originalScreen, int originalDpi)
-    {
-        var displayArea = DisplayArea.GetFromRect(windowRect, DisplayAreaFallback.Nearest);
-        if (displayArea is null)
-        {
-            return windowRect;
-        }
-
-        var workArea = displayArea.WorkArea;
-        if (workArea.Width <= 0 || workArea.Height <= 0)
-        {
-            // Fallback, nothing reasonable to do
-            return windowRect;
-        }
-
-        var effectiveDpi = GetEffectiveDpiFromDisplayId(displayArea);
-        if (originalDpi <= 0)
-        {
-            originalDpi = effectiveDpi; // use current DPI as baseline (no scaling adjustment needed)
-        }
-
-        var hasInvalidSize = windowRect.Width <= 0 || windowRect.Height <= 0;
-        if (hasInvalidSize)
-        {
-            windowRect = new RectInt32(windowRect.X, windowRect.Y, DefaultWidth, DefaultHeight);
-        }
-
-        // If we have a DPI change, scale the window rectangle accordingly
-        if (effectiveDpi != originalDpi)
-        {
-            var scalingFactor = effectiveDpi / (double)originalDpi;
-            windowRect = new RectInt32(
-                (int)Math.Round(windowRect.X * scalingFactor),
-                (int)Math.Round(windowRect.Y * scalingFactor),
-                (int)Math.Round(windowRect.Width * scalingFactor),
-                (int)Math.Round(windowRect.Height * scalingFactor));
-        }
-
-        var targetWidth = Math.Min(windowRect.Width, workArea.Width);
-        var targetHeight = Math.Min(windowRect.Height, workArea.Height);
-
-        // Ensure at least some minimum visible area (e.g., 100 pixels)
-        // This helps prevent the window from being entirely offscreen, regardless of display scaling.
-        const int minimumVisibleSize = 100;
-        var isOffscreen =
-            windowRect.X + minimumVisibleSize > workArea.X + workArea.Width ||
-            windowRect.X + windowRect.Width - minimumVisibleSize < workArea.X ||
-            windowRect.Y + minimumVisibleSize > workArea.Y + workArea.Height ||
-            windowRect.Y + windowRect.Height - minimumVisibleSize < workArea.Y;
-
-        // if the work area size has changed, re-center the window
-        var workAreaSizeChanged =
-            originalScreen.Width != workArea.Width ||
-            originalScreen.Height != workArea.Height;
-
-        int targetX;
-        int targetY;
-        var recenter = isOffscreen || workAreaSizeChanged || hasInvalidSize;
-        if (recenter)
-        {
-            targetX = workArea.X + ((workArea.Width - targetWidth) / 2);
-            targetY = workArea.Y + ((workArea.Height - targetHeight) / 2);
-        }
-        else
-        {
-            targetX = windowRect.X;
-            targetY = windowRect.Y;
-        }
-
-        return new RectInt32(targetX, targetY, targetWidth, targetHeight);
-    }
-
-    private static int GetEffectiveDpiFromDisplayId(DisplayArea displayArea)
-    {
-        var effectiveDpi = 96;
-
-        var hMonitor = (HMONITOR)Win32Interop.GetMonitorFromDisplayId(displayArea.DisplayId);
-        if (!hMonitor.IsNull)
-        {
-            var hr = PInvoke.GetDpiForMonitor(hMonitor, MONITOR_DPI_TYPE.MDT_EFFECTIVE_DPI, out var dpiX, out _);
-            if (hr == 0)
-            {
-                effectiveDpi = (int)dpiX;
-            }
-            else
-            {
-                Logger.LogWarning($"GetDpiForMonitor failed with HRESULT: 0x{hr.Value:X8} on display {displayArea.DisplayId}");
-            }
-        }
-
-        if (effectiveDpi <= 0)
-        {
-            effectiveDpi = 96;
-        }
-
-        return effectiveDpi;
-    }
-
-    private DisplayArea GetScreen(HWND currentHwnd, MonitorBehavior target)
+    private static DisplayArea GetScreen(HWND currentHwnd, MonitorBehavior target)
     {
         // Leaving a note here, in case we ever need it:
         // https://github.com/microsoft/microsoft-ui-xaml/issues/6454

src/modules/cmdpal/Microsoft.CmdPal.UI/Microsoft.CmdPal.UI.csproj

@@ -83,6 +83,7 @@
     <None Remove="Pages\Settings\GeneralPage.xaml" />
     <None Remove="SettingsWindow.xaml" />
     <None Remove="Settings\AppearancePage.xaml" />
+    <None Remove="Settings\InternalPage.xaml" />
     <None Remove="ShellPage.xaml" />
     <None Remove="Styles\Colors.xaml" />
     <None Remove="Styles\Settings.xaml" />
@@ -264,6 +265,11 @@
       <Generator>MSBuild:Compile</Generator>
     </Page>
   </ItemGroup>
+  <ItemGroup>
+    <Page Update="Settings\InternalPage.xaml">
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
+  </ItemGroup>
   <ItemGroup>
     <Page Update="Styles\Colors.xaml">
       <Generator>MSBuild:Compile</Generator>

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

@@ -257,11 +257,11 @@ public sealed partial class ShellPage : Microsoft.UI.Xaml.Controls.Page,
     {
         _ = DispatcherQueue.TryEnqueue(() =>
         {
-            OpenSettings();
+            OpenSettings(message.SettingsPageTag);
         });
     }
 
-    public void OpenSettings()
+    public void OpenSettings(string pageTag)
     {
         if (_settingsWindow is null)
         {
@@ -270,6 +270,7 @@ public sealed partial class ShellPage : Microsoft.UI.Xaml.Controls.Page,
 
         _settingsWindow.Activate();
         _settingsWindow.BringToFront();
+        _settingsWindow.Navigate(pageTag);
     }
 
     public void Receive(ShowDetailsMessage message)

src/modules/cmdpal/Microsoft.CmdPal.UI/Settings/ExtensionsPage.xaml

@@ -229,12 +229,26 @@
                                     <controls:SettingsCard.HeaderIcon>
                                         <cpcontrols:ContentIcon>
                                             <cpcontrols:ContentIcon.Content>
-                                                <cpcontrols:IconBox
-                                                    Width="20"
-                                                    Height="20"
+                                                <controls:SwitchPresenter
                                                     AutomationProperties.AccessibilityView="Raw"
-                                                    SourceKey="{x:Bind Icon, Mode=OneWay}"
-                                                    SourceRequested="{x:Bind helpers:IconCacheProvider.SourceRequested}" />
+                                                    TargetType="x:Boolean"
+                                                    Value="{x:Bind Icon.IsSet, FallbackValue=x:False, Mode=OneWay}">
+                                                    <controls:Case Value="True">
+                                                        <cpcontrols:IconBox
+                                                            Width="20"
+                                                            Height="20"
+                                                            AutomationProperties.AccessibilityView="Raw"
+                                                            SourceKey="{x:Bind Icon, Mode=OneWay}"
+                                                            SourceRequested="{x:Bind helpers:IconCacheProvider.SourceRequested}" />
+                                                    </controls:Case>
+                                                    <controls:Case Value="False">
+                                                        <Image
+                                                            Width="20"
+                                                            Height="20"
+                                                            AutomationProperties.AccessibilityView="Raw"
+                                                            Source="ms-appx:///Assets/Icons/ExtensionIconPlaceholder.png" />
+                                                    </controls:Case>
+                                                </controls:SwitchPresenter>
                                             </cpcontrols:ContentIcon.Content>
                                         </cpcontrols:ContentIcon>
                                     </controls:SettingsCard.HeaderIcon>

src/modules/cmdpal/Microsoft.CmdPal.UI/Settings/InternalPage.SampleData.cs

@@ -0,0 +1,45 @@
+// 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.UI.Settings;
+
+public partial class InternalPage
+{
+    internal static class SampleData
+    {
+        internal static string ExceptionMessageWithPii { get; } =
+            $"""
+             Test exception with personal information; thrown from the UI thread
+
+             Here is e-mail address <jane.doe@contoso.com>
+             IPv4 address: 192.168.100.1
+             IPv4 loopback address: 127.0.0.1
+             MAC address: 00-14-22-01-23-45
+             IPv6 address: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
+             IPv6 loopback address: ::1
+             Password: P@ssw0rd123!
+             Password=secret
+             Api key: 1234567890abcdef
+             PostgreSQL connection string: Host=localhost;Username=postgres;Password=secret;Database=mydb
+             InstrumentationKey=00000000-0000-0000-0000-000000000000;EndpointSuffix=ai.contoso.com;
+             X-API-key: 1234567890abcdef
+             Pet-Shop-Subscription-Key: 1234567890abcdef
+             Here is a user name {Environment.UserName}
+             And here is a profile path {Environment.GetFolderPath(Environment.SpecialFolder.UserProfile)}\Pictures
+             Here is a local app data path {Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData)}\Microsoft\PowerToys\CmdPal
+             Here is machine name {Environment.MachineName}
+             JWT token: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWUsImlhdCI6MTUxNjIzOTAyMn0.KMUFsIDTnFmyG3nMiGM6H9FNFUROf3wh7SmqJp-QV30
+             User email john.doe@company.com failed validation
+             File not found: {Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)}\\secret.txt
+             Connection string: Server=localhost;User ID=admin;Password=secret123;Database=test
+             Phone number 555-123-4567 is invalid
+             API key abc123def456ghi789jkl012mno345pqr678 expired
+             Failed to connect to https://api.internal-company.com/users/12345?token=secret_abc123
+             Error accessing file://C:/Users/john.doe/Documents/confidential.pdf
+             JDBC connection failed: jdbc://database-server:5432/userdb?user=admin&password=secret
+             FTP upload error: ftp://internal-server.company.com/uploads/user_data.csv
+             Email service error: mailto:admin@internal-company.com?subject=Alert
+             """;
+    }
+}

src/modules/cmdpal/Microsoft.CmdPal.UI/Settings/InternalPage.xaml

@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<Page
+    x:Class="Microsoft.CmdPal.UI.Settings.InternalPage"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:controls="using:CommunityToolkit.WinUI.Controls"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    xmlns:ui="using:CommunityToolkit.WinUI"
+    mc:Ignorable="d">
+
+    <Grid>
+        <Grid.RowDefinitions>
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="*" />
+        </Grid.RowDefinitions>
+        <ScrollViewer Grid.Row="1">
+            <Grid Padding="16">
+                <StackPanel
+                    MaxWidth="1000"
+                    HorizontalAlignment="Stretch"
+                    Spacing="{StaticResource SettingsCardSpacing}">
+
+                    <TextBlock Style="{StaticResource BodyTextBlockStyle}" Text="Tools on this page are for internal use only. This page is not visible in CI builds." />
+
+                    <!--  Exception Handling Section  -->
+                    <TextBlock Style="{StaticResource SettingsSectionHeaderTextBlockStyle}" Text="Exception Handling" />
+                    <controls:SettingsExpander
+                        Description="Actions for testing global exception handling from the application"
+                        Header="Throw exceptions"
+                        HeaderIcon="{ui:FontIcon Glyph=&#xE783;}"
+                        IsExpanded="True">
+                        <controls:SettingsExpander.Items>
+                            <controls:SettingsCard Header="Throw an unhandled exception from the UI thread">
+                                <Button Click="ThrowPlainMainThreadException_Click" Content="Throw" />
+                            </controls:SettingsCard>
+                            <controls:SettingsCard Header="Throw an unhandled exception from the UI thread (with PII)">
+                                <Button Click="ThrowPlainMainThreadExceptionPii_Click" Content="Throw" />
+                            </controls:SettingsCard>
+                            <controls:SettingsCard Description="Throw with delay, when the task is collected by the GC" Header="Throw unobserved exception from a task">
+                                <Button Click="ThrowExceptionInUnobservedTask_Click" Content="Throw" />
+                            </controls:SettingsCard>
+                        </controls:SettingsExpander.Items>
+                    </controls:SettingsExpander>
+
+                    <!--  Diagnostics Section  -->
+                    <TextBlock Style="{StaticResource SettingsSectionHeaderTextBlockStyle}" Text="Diagnostics" />
+                    <controls:SettingsCard
+                        x:Name="LogsSettingsCard"
+                        Header="Logs folder"
+                        HeaderIcon="{ui:FontIcon Glyph=&#xE8B7;}">
+                        <Button Click="OpenLogsCardClicked" Content="Open folder" />
+                    </controls:SettingsCard>
+                    <controls:SettingsCard
+                        x:Name="CurrentLogFileSettingsCard"
+                        Header="Current log file"
+                        HeaderIcon="{ui:FontIcon Glyph=&#xF7BB;}">
+                        <Button Click="OpenCurrentLogCardClicked" Content="Open log" />
+                    </controls:SettingsCard>
+
+                    <!--  Data Section  -->
+                    <TextBlock Style="{StaticResource SettingsSectionHeaderTextBlockStyle}" Text="Data and Files" />
+                    <controls:SettingsCard
+                        x:Name="ConfigurationFolderSettingsCard"
+                        Header="Configuration folder"
+                        HeaderIcon="{ui:FontIcon Glyph=&#xF73D;}">
+                        <Button Click="OpenConfigFolderCardClick" Content="Open folder" />
+                    </controls:SettingsCard>
+
+
+                </StackPanel>
+            </Grid>
+        </ScrollViewer>
+    </Grid>
+</Page>

src/modules/cmdpal/Microsoft.CmdPal.UI/Settings/InternalPage.xaml.cs

@@ -0,0 +1,92 @@
+// 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 ManagedCommon;
+using Microsoft.CommandPalette.Extensions.Toolkit;
+using Microsoft.UI.Xaml;
+using Windows.System;
+using Page = Microsoft.UI.Xaml.Controls.Page;
+
+namespace Microsoft.CmdPal.UI.Settings;
+
+/// <summary>
+/// An empty page that can be used on its own or navigated to within a Frame.
+/// </summary>
+public sealed partial class InternalPage : Page
+{
+    public InternalPage()
+    {
+        InitializeComponent();
+    }
+
+    private void ThrowPlainMainThreadException_Click(object sender, RoutedEventArgs e)
+    {
+        Logger.LogDebug("Throwing test exception from the UI thread");
+        throw new NotImplementedException("Test exception; thrown from the UI thread");
+    }
+
+    private void ThrowExceptionInUnobservedTask_Click(object sender, RoutedEventArgs e)
+    {
+        Logger.LogDebug("Starting a task that will throw test exception");
+        Task.Run(() =>
+        {
+            Logger.LogDebug("Throwing test exception from a task");
+            throw new InvalidOperationException("Test exception; thrown from a task");
+        });
+    }
+
+    private void ThrowPlainMainThreadExceptionPii_Click(object sender, RoutedEventArgs e)
+    {
+        Logger.LogDebug("Throwing test exception from the UI thread (PII)");
+        throw new InvalidOperationException(SampleData.ExceptionMessageWithPii);
+    }
+
+    private async void OpenLogsCardClicked(object sender, RoutedEventArgs e)
+    {
+        try
+        {
+            var logFolderPath = Logger.CurrentVersionLogDirectoryPath;
+            if (Directory.Exists(logFolderPath))
+            {
+                await Launcher.LaunchFolderPathAsync(logFolderPath);
+            }
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError("Failed to open directory in Explorer", ex);
+        }
+    }
+
+    private async void OpenCurrentLogCardClicked(object sender, RoutedEventArgs e)
+    {
+        try
+        {
+            var logPath = Logger.CurrentLogFile;
+            if (File.Exists(logPath))
+            {
+                await Launcher.LaunchUriAsync(new Uri(logPath));
+            }
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError("Failed to open log file", ex);
+        }
+    }
+
+    private async void OpenConfigFolderCardClick(object sender, RoutedEventArgs e)
+    {
+        try
+        {
+            var directory = Utilities.BaseSettingsPath("Microsoft.CmdPal");
+            if (Directory.Exists(directory))
+            {
+                await Launcher.LaunchFolderPathAsync(directory);
+            }
+        }
+        catch (Exception ex)
+        {
+            Logger.LogError("Failed to open directory in Explorer", ex);
+        }
+    }
+}

src/modules/cmdpal/Microsoft.CmdPal.UI/Settings/SettingsWindow.xaml

@@ -72,6 +72,7 @@
                     x:Uid="Settings_GeneralPage_NavigationViewItem_Extensions"
                     Icon="{ui:FontIcon Glyph=}"
                     Tag="Extensions" />
+                <!--  "Internal Tools" page item is added dynamically from code  -->
             </NavigationView.MenuItems>
             <Grid>
                 <Grid.RowDefinitions>

src/modules/cmdpal/Microsoft.CmdPal.UI/Settings/SettingsWindow.xaml.cs

@@ -30,6 +30,8 @@ public sealed partial class SettingsWindow : WindowEx,
 {
     private readonly LocalKeyboardListener _localKeyboardListener;
 
+    private readonly NavigationViewItem? _internalNavItem;
+
     public ObservableCollection<Crumb> BreadCrumbs { get; } = [];
 
     // Gets or sets optional action invoked after NavigationView is loaded.
@@ -54,6 +56,23 @@ public sealed partial class SettingsWindow : WindowEx,
         _localKeyboardListener.Start();
         Closed += SettingsWindow_Closed;
         RootElement.AddHandler(UIElement.PointerPressedEvent, new PointerEventHandler(RootElement_OnPointerPressed), true);
+
+        if (!BuildInfo.IsCiBuild)
+        {
+            _internalNavItem = new NavigationViewItem
+            {
+                Content = "Internal Tools",
+                Icon = new FontIcon { Glyph = "\uEC7A" },
+                Tag = "Internal",
+            };
+            NavView.MenuItems.Add(_internalNavItem);
+        }
+        else
+        {
+            _internalNavItem = null;
+        }
+
+        Navigate("General");
     }
 
     private void SettingsWindow_Closed(object sender, WindowEventArgs args)
@@ -68,9 +87,6 @@ public sealed partial class SettingsWindow : WindowEx,
         // Delay necessary to ensure NavigationView visual state can match navigation
         Task.Delay(500).ContinueWith(_ => this.NavigationViewLoaded?.Invoke(), TaskScheduler.FromCurrentSynchronizationContext());
 
-        NavView.SelectedItem = NavView.MenuItems[0];
-        Navigate("General");
-
         if (sender is NavigationView navigationView)
         {
             // Register for pane open/close changes to announce to screen readers
@@ -96,15 +112,33 @@ public sealed partial class SettingsWindow : WindowEx,
         Navigate((selectedItem.Tag as string)!);
     }
 
-    private void Navigate(string page)
+    internal void Navigate(string page)
     {
-        var pageType = page switch
+        Type? pageType;
+        switch (page)
         {
-            "General" => typeof(GeneralPage),
-            "Appearance" => typeof(AppearancePage),
-            "Extensions" => typeof(ExtensionsPage),
-            _ => null,
-        };
+            case "General":
+                pageType = typeof(GeneralPage);
+                break;
+            case "Appearance":
+                pageType = typeof(AppearancePage);
+                break;
+            case "Extensions":
+                pageType = typeof(ExtensionsPage);
+                break;
+            case "Internal":
+                pageType = typeof(InternalPage);
+                break;
+            case "":
+                // intentional no-op: empty tag means no navigation
+                pageType = null;
+                break;
+            default:
+                // unknown page, no-op and log
+                pageType = null;
+                Logger.LogError($"Unknown settings page tag '{page}'");
+                break;
+        }
 
         if (pageType is not null)
         {
@@ -268,6 +302,12 @@ public sealed partial class SettingsWindow : WindowEx,
             BreadCrumbs.Add(new(extensionsPageType, extensionsPageType));
             BreadCrumbs.Add(new(vm.DisplayName, vm));
         }
+        else if (e.SourcePageType == typeof(InternalPage) && _internalNavItem is not null)
+        {
+            NavView.SelectedItem = _internalNavItem;
+            var pageType = "Internal";
+            BreadCrumbs.Add(new(pageType, pageType));
+        }
         else
         {
             BreadCrumbs.Add(new($"[{e.SourcePageType?.Name}]", string.Empty));

src/modules/cmdpal/Microsoft.CmdPal.UI/ViewModels/DevRibbonViewModel.cs

@@ -8,8 +8,10 @@ using System.Globalization;
 using System.Text.RegularExpressions;
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
+using CommunityToolkit.Mvvm.Messaging;
 using ManagedCommon;
 using Microsoft.CmdPal.UI.Helpers;
+using Microsoft.CmdPal.UI.Messages;
 using Microsoft.UI;
 using Windows.System;
 using Windows.UI;
@@ -99,6 +101,12 @@ internal sealed partial class DevRibbonViewModel : ObservableObject
         LatestLogs.Clear();
     }
 
+    [RelayCommand]
+    private void OpenInternalTools()
+    {
+        WeakReferenceMessenger.Default.Send(new OpenSettingsMessage("Internal"));
+    }
+
     private sealed partial class DevRibbonTraceListener(DevRibbonViewModel viewModel) : TraceListener
     {
         private const string TimestampFormat = "yyyy-MM-dd HH:mm:ss.fff";

src/modules/cmdpal/Tests/Microsoft.CmdPal.Core.Common.UnitTests/GlobalUsings.cs

@@ -0,0 +1,9 @@
+// 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.
+
+global using System;
+global using System.Collections.Generic;
+global using System.Diagnostics.CodeAnalysis;
+global using System.Linq;
+global using Microsoft.VisualStudio.TestTools.UnitTesting;

src/modules/cmdpal/Tests/Microsoft.CmdPal.Core.Common.UnitTests/Microsoft.CmdPal.Core.Common.UnitTests.csproj

@@ -0,0 +1,25 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <!-- Look at Directory.Build.props in root for common stuff as well -->
+  <Import Project="..\..\..\..\Common.Dotnet.CsWinRT.props" />
+
+  <PropertyGroup>
+    <IsPackable>false</IsPackable>
+    <IsTestProject>true</IsTestProject>
+    <RootNamespace>Microsoft.CmdPal.Common.UnitTests</RootNamespace>
+    <OutputPath>$(SolutionDir)$(Platform)\$(Configuration)\WinUI3Apps\CmdPal\tests\</OutputPath>
+    <AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
+    <AppendRuntimeIdentifierToOutputPath>false</AppendRuntimeIdentifierToOutputPath>
+    <Nullable>enable</Nullable>
+    <LangVersion>preview</LangVersion>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Moq" />
+    <PackageReference Include="MSTest" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\..\Core\Microsoft.CmdPal.Core.Common\Microsoft.CmdPal.Core.Common.csproj" />
+    <ProjectReference Include="..\Microsoft.CmdPal.Ext.UnitTestsBase\Microsoft.CmdPal.Ext.UnitTestBase.csproj" />
+  </ItemGroup>
+</Project>

src/modules/cmdpal/Tests/Microsoft.CmdPal.Core.Common.UnitTests/Services/Sanitizer/ConnectionStringRuleProviderTests.cs

@@ -0,0 +1,107 @@
+// 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 Microsoft.CmdPal.Common.UnitTests.TestUtils;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Common.UnitTests.Services.Sanitizer;
+
+[TestClass]
+public class ConnectionStringRuleProviderTests
+{
+    [TestMethod]
+    public void GetRules_ShouldReturnExpectedRules()
+    {
+        // Arrange
+        var provider = new ConnectionStringRuleProvider();
+
+        // Act
+        var rules = provider.GetRules();
+
+        // Assert
+        var ruleList = new List<SanitizationRule>(rules);
+        Assert.AreEqual(1, ruleList.Count);
+        Assert.AreEqual("Connection string parameters", ruleList[0].Description);
+    }
+
+    [DataTestMethod]
+    [DataRow("Server=localhost;Database=mydb;User ID=admin;Password=secret123", "Server=[REDACTED];Database=[REDACTED];User ID=[REDACTED];Password=[REDACTED]")]
+    [DataRow("Data Source=server.example.com;Initial Catalog=testdb;Uid=user;Pwd=pass", "Data Source=[REDACTED];Initial Catalog=[REDACTED];Uid=[REDACTED];Pwd=[REDACTED]")]
+    [DataRow("Server=localhost;Password=my_secret", "Server=[REDACTED];Password=[REDACTED]")]
+    [DataRow("No connection string here", "No connection string here")]
+    public void ConnectionStringRules_ShouldMaskConnectionStringParameters(string input, string expected)
+    {
+        // Arrange
+        var provider = new ConnectionStringRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("Password=\"complexPassword123!\"", "Password=[REDACTED]")]
+    [DataRow("Password='myPassword'", "Password=[REDACTED]")]
+    [DataRow("Password=unquotedSecret", "Password=[REDACTED]")]
+    public void ConnectionStringRules_ShouldHandleQuotedAndUnquotedValues(string input, string expected)
+    {
+        // Arrange
+        var provider = new ConnectionStringRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("SERVER=server1;PASSWORD=pass1", "SERVER=[REDACTED];PASSWORD=[REDACTED]")]
+    [DataRow("server=server1;password=pass1", "server=[REDACTED];password=[REDACTED]")]
+    [DataRow("Server=server1;Password=pass1", "Server=[REDACTED];Password=[REDACTED]")]
+    public void ConnectionStringRules_ShouldBeCaseInsensitive(string input, string expected)
+    {
+        // Arrange
+        var provider = new ConnectionStringRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("User ID=admin;Username=john;Password=secret", "User ID=[REDACTED];Username=[REDACTED];Password=[REDACTED]")]
+    [DataRow("Database=mydb;Uid=user1;Pwd=pass1;Server=localhost", "Database=[REDACTED];Uid=[REDACTED];Pwd=[REDACTED];Server=[REDACTED]")]
+    public void ConnectionStringRules_ShouldHandleMultipleParameters(string input, string expected)
+    {
+        // Arrange
+        var provider = new ConnectionStringRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("Server = localhost ; Password = secret123", "Server=[REDACTED] ; Password=[REDACTED]")]
+    [DataRow("Initial Catalog=db;  User ID=admin;  Password=pass", "Initial Catalog=[REDACTED];  User ID=[REDACTED];  Password=[REDACTED]")]
+    public void ConnectionStringRules_ShouldHandleWhitespace(string input, string expected)
+    {
+        // Arrange
+        var provider = new ConnectionStringRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CmdPal.Core.Common.UnitTests/Services/Sanitizer/ErrorReportSanitizerTests.TestData.cs

@@ -0,0 +1,81 @@
+// 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.Common.UnitTests.Services.Sanitizer;
+
+public partial class ErrorReportSanitizerTests
+{
+    private static class TestData
+    {
+        internal static string Input =>
+             $"""
+              HRESULT: 0x80004005
+              HRESULT: -2147467259
+
+              Here is e-mail address <jane.doe@contoso.com>
+              IPv4 address: 192.168.100.1
+              IPv4 loopback address: 127.0.0.1
+              MAC address: 00-14-22-01-23-45
+              IPv6 address: 2001:0db8:85a3:0000:0000:8a2e:0370:7334
+              IPv6 loopback address: ::1
+              Password: P@ssw0rd123!
+              Password=secret
+              Api key: 1234567890abcdef
+              PostgreSQL connection string: Host=localhost;Username=postgres;Password=secret;Database=mydb
+              InstrumentationKey=00000000-0000-0000-0000-000000000000;EndpointSuffix=ai.contoso.com;
+              X-API-key: 1234567890abcdef
+              Pet-Shop-Subscription-Key: 1234567890abcdef
+              Here is a user name {Environment.UserName}
+              And here is a profile path {Environment.GetFolderPath(Environment.SpecialFolder.UserProfile)}\RandomFolder
+              Here is a local app data path {Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData)}\Microsoft\PowerToys\CmdPal
+              Here is machine name {Environment.MachineName}
+              JWT token: eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiYWRtaW4iOnRydWUsImlhdCI6MTUxNjIzOTAyMn0.KMUFsIDTnFmyG3nMiGM6H9FNFUROf3wh7SmqJp-QV30
+              User email john.doe@company.com failed validation
+              File not found: {Environment.GetFolderPath(Environment.SpecialFolder.MyDocuments)}\\secret.txt
+              Connection string: Server=localhost;User ID=admin;Password=secret123;Database=test
+              Phone number 555-123-4567 is invalid
+              API key abc123def456ghi789jkl012mno345pqr678 expired
+              Failed to connect to https://api.internal-company.com/users/12345?token=secret_abc123
+              Error accessing file://C:/Users/john.doe/Documents/confidential.pdf
+              JDBC connection failed: jdbc://database-server:5432/userdb?user=admin&password=secret
+              FTP upload error: ftp://internal-server.company.com/uploads/user_data.csv
+              Email service error: mailto:admin@internal-company.com?subject=Alert
+              """;
+
+        public const string Expected =
+            $"""
+             HRESULT: 0x80004005
+             HRESULT: -2147467259
+
+             Here is e-mail address <[EMAIL_REDACTED]>
+             IPv4 address: [IP4_REDACTED]
+             IPv4 loopback address: [IP4_REDACTED]
+             MAC address: [MAC_ADDRESS_REDACTED]
+             IPv6 address: [IP6_REDACTED]
+             IPv6 loopback address: [IP6_REDACTED]
+             Password: [REDACTED]
+             Password= [REDACTED]
+             Api key: [REDACTED]
+             PostgreSQL connection string: [REDACTED]
+             InstrumentationKey= [REDACTED]
+             X-API-key: [REDACTED]
+             Pet-Shop-Subscription-Key: [REDACTED]
+             Here is a user name [USERNAME_REDACTED]
+             And here is a profile path [USER_PROFILE_DIR]RandomFolder
+             Here is a local app data path [LOCALAPPLICATIONDATA_DIR]Microsoft\PowerToys\CmdPal
+             Here is machine name [MACHINE_NAME_REDACTED]
+             JWT token: [REDACTED]
+             User email [EMAIL_REDACTED] failed validation
+             File not found: [MYDOCUMENTS_DIR]se****.txt
+             Connection string: [REDACTED] ID=[REDACTED];Password= [REDACTED]
+             Phone number [PHONE_REDACTED] is invalid
+             API key [TOKEN_REDACTED] expired
+             Failed to connect to [URL_REDACTED]
+             Error accessing [URL_REDACTED]
+             JDBC connection failed: [URL_REDACTED]
+             FTP upload error: [URL_REDACTED]
+             Email service error: mailto:[EMAIL_REDACTED]?subject=Alert
+             """;
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CmdPal.Core.Common.UnitTests/Services/Sanitizer/ErrorReportSanitizerTests.cs

@@ -0,0 +1,25 @@
+// 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 Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+
+namespace Microsoft.CmdPal.Common.UnitTests.Services.Sanitizer;
+
+[TestClass]
+public partial class ErrorReportSanitizerTests
+{
+    [TestMethod]
+    public void Sanitize_ShouldMaskPiiInErrorReport()
+    {
+        // Arrange
+        var reportSanitizer = new ErrorReportSanitizer();
+        var input = TestData.Input;
+
+        // Act
+        var result = reportSanitizer.Sanitize(input);
+
+        // Assert
+        Assert.AreEqual(TestData.Expected, result);
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CmdPal.Core.Common.UnitTests/Services/Sanitizer/PiiRuleProviderTests.cs

@@ -0,0 +1,122 @@
+// 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 Microsoft.CmdPal.Common.UnitTests.TestUtils;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Common.UnitTests.Services.Sanitizer;
+
+[TestClass]
+public class PiiRuleProviderTests
+{
+    [TestMethod]
+    public void GetRules_ShouldReturnExpectedRules()
+    {
+        // Arrange
+        var provider = new PiiRuleProvider();
+
+        // Act
+        var rules = provider.GetRules();
+
+        // Assert
+        var ruleList = new List<SanitizationRule>(rules);
+        Assert.AreEqual(4, ruleList.Count);
+        Assert.AreEqual("Email addresses", ruleList[0].Description);
+        Assert.AreEqual("Social Security Numbers", ruleList[1].Description);
+        Assert.AreEqual("Credit card numbers", ruleList[2].Description);
+        Assert.AreEqual("Phone numbers", ruleList[3].Description);
+    }
+
+    [DataTestMethod]
+    [DataRow("Contact me at john.doe@contoso.com", "Contact me at [EMAIL_REDACTED]")]
+    [DataRow("Contact me at a_b-c%2@foo-bar.example.co.uk", "Contact me at [EMAIL_REDACTED]")]
+    [DataRow("My email is john@sub-domain.contoso.com.", "My email is [EMAIL_REDACTED].")]
+    [DataRow("Two: a@b.com and c@d.org", "Two: [EMAIL_REDACTED] and [EMAIL_REDACTED]")]
+    [DataRow("No email here", "No email here")]
+    public void EmailRules_ShouldMaskEmailAddresses(string input, string expected)
+    {
+        // Arrange
+        var provider = new PiiRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("Call me at 123-456-7890", "Call me at [PHONE_REDACTED]")]
+    [DataRow("My number is (123) 456-7890.", "My number is [PHONE_REDACTED].")]
+    [DataRow("Office: +1 123 456 7890", "Office: [PHONE_REDACTED]")]
+    [DataRow("Two numbers: 123-456-7890 and +420 777123456", "Two numbers: [PHONE_REDACTED] and [PHONE_REDACTED]")]
+    [DataRow("Czech phone +420 777 123 456", "Czech phone [PHONE_REDACTED]")]
+    [DataRow("Slovak phone +421 777 12 34 56", "Slovak phone [PHONE_REDACTED]")]
+    [DataRow("No phone number here", "No phone number here")]
+    public void PhoneRules_ShouldMaskPhoneNumbers(string input, string expected)
+    {
+        // Arrange
+        var provider = new PiiRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("My SSN is 123-45-6789", "My SSN is [SSN_REDACTED]")]
+    [DataRow("No SSN here", "No SSN here")]
+    public void SsnRules_ShouldMaskSsn(string input, string expected)
+    {
+        // Arrange
+        var provider = new PiiRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("My credit card number is 1234-5678-9012-3456", "My credit card number is [CARD_REDACTED]")]
+    [DataRow("My credit card number is 1234567890123456", "My credit card number is [CARD_REDACTED]")]
+    [DataRow("No credit card here", "No credit card here")]
+    public void CreditCardRules_ShouldMaskCreditCardNumbers(string input, string expected)
+    {
+        // Arrange
+        var provider = new PiiRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("Error code: 0x80070005", "Error code: 0x80070005")]
+    [DataRow("Error code: -2147467262", "Error code: -2147467262")]
+    [DataRow("GUID: 123e4567-e89b-12d3-a456-426614174000", "GUID: 123e4567-e89b-12d3-a456-426614174000")]
+    [DataRow("Timestamp: 2023-10-05T14:32:10Z", "Timestamp: 2023-10-05T14:32:10Z")]
+    [DataRow("Version: 1.2.3", "Version: 1.2.3")]
+    [DataRow("Version: 10.0.22631.3448", "Version: 10.0.22631.3448")]
+    [DataRow("MAC: 00:1A:2B:3C:4D:5E", "MAC: 00:1A:2B:3C:4D:5E")]
+    [DataRow("Date: 2023-10-05", "Date: 2023-10-05")]
+    [DataRow("Date: 05/10/2023", "Date: 05/10/2023")]
+    public void PiiRuleProvider_ShouldNotOverRedact(string input, string expected)
+    {
+        // Arrange
+        var provider = new PiiRuleProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CmdPal.Core.Common.UnitTests/Services/Sanitizer/SecretKeyValueRulesProviderTests.cs

@@ -0,0 +1,266 @@
+// 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 Microsoft.CmdPal.Common.UnitTests.TestUtils;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Common.UnitTests.Services.Sanitizer;
+
+[TestClass]
+public class SecretKeyValueRulesProviderTests
+{
+    [TestMethod]
+    public void GetRules_ShouldReturnExpectedRules()
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var rules = provider.GetRules();
+
+        // Assert
+        var ruleList = new List<SanitizationRule>(rules);
+        Assert.AreEqual(1, ruleList.Count);
+        Assert.AreEqual("Sensitive key/value pairs", ruleList[0].Description);
+    }
+
+    [DataTestMethod]
+    [DataRow("password=secret123", "password= [REDACTED]")]
+    [DataRow("passphrase=myPassphrase", "passphrase= [REDACTED]")]
+    [DataRow("pwd=test", "pwd= [REDACTED]")]
+    [DataRow("passwd=pass1234", "passwd= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldMaskPasswordSecrets(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("token=abc123def456", "token= [REDACTED]")]
+    [DataRow("access_token=token_value", "access_token= [REDACTED]")]
+    [DataRow("refresh-token=refresh_value", "refresh-token= [REDACTED]")]
+    [DataRow("id token=id_token_value", "id token= [REDACTED]")]
+    [DataRow("bearer token=bearer_value", "bearer token= [REDACTED]")]
+    [DataRow("session token=session_value", "session token= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldMaskTokens(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("api key=my_api_key", "api key= [REDACTED]")]
+    [DataRow("api-key=key123", "api-key= [REDACTED]")]
+    [DataRow("api_key=secret_key", "api_key= [REDACTED]")]
+    [DataRow("x-api-key=api123", "x-api-key= [REDACTED]")]
+    [DataRow("x api key=key456", "x api key= [REDACTED]")]
+    [DataRow("client id=client123", "client id= [REDACTED]")]
+    [DataRow("client-secret=secret123", "client-secret= [REDACTED]")]
+    [DataRow("consumer secret=secret456", "consumer secret= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldMaskApiCredentials(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("subscription key=sub_key_123", "subscription key= [REDACTED]")]
+    [DataRow("instrumentation key=instr_key", "instrumentation key= [REDACTED]")]
+    [DataRow("account key=account123", "account key= [REDACTED]")]
+    [DataRow("storage account key=storage_key", "storage account key= [REDACTED]")]
+    [DataRow("shared access key=sak123", "shared access key= [REDACTED]")]
+    [DataRow("SAS token=sas123", "SAS token= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldMaskCloudPlatformKeys(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("connection string=Server=localhost;Pwd=pass", "connection string= [REDACTED]")]
+    [DataRow("conn string=conn_value", "conn string= [REDACTED]")]
+    [DataRow("storage connection string=connection_value", "storage connection string= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldMaskConnectionStrings(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("private key=pk123", "private key= [REDACTED]")]
+    [DataRow("certificate password=cert_pass", "certificate password= [REDACTED]")]
+    [DataRow("client certificate password=cert123", "client certificate password= [REDACTED]")]
+    [DataRow("pfx password=pfx_pass", "pfx password= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldMaskCertificateSecrets(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("aws access key id=AKIAIOSFODNN7EXAMPLE", "aws access key id= [REDACTED]")]
+    [DataRow("aws secret access key=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY", "aws secret access key= [REDACTED]")]
+    [DataRow("aws session token=session_token_value", "aws session token= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldMaskAwsKeys(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("password=\"complexPassword123!\"", "password= \"[REDACTED]\"")]
+    [DataRow("api-key='secret-key'", "api-key= '[REDACTED]'")]
+    [DataRow("token=\"bearer_token_value\"", "token= \"[REDACTED]\"")]
+    public void SecretKeyValueRules_ShouldPreserveQuotesAroundRedactedValue(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("PASSWORD=secret", "PASSWORD= [REDACTED]")]
+    [DataRow("Api-Key=key123", "Api-Key= [REDACTED]")]
+    [DataRow("CLIENT_ID=client123", "CLIENT_ID= [REDACTED]")]
+    [DataRow("Pwd=pass123", "Pwd= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldBeCaseInsensitive(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("regularKey=regularValue", "regularKey=regularValue")]
+    [DataRow("config=myConfig", "config=myConfig")]
+    [DataRow("hostname=server.example.com", "hostname=server.example.com")]
+    [DataRow("port=8080", "port=8080")]
+    public void SecretKeyValueRules_ShouldNotRedactNonSecretKeyValuePairs(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("password:secret123", "password: [REDACTED]")]
+    [DataRow("api key:api_key_value", "api key: [REDACTED]")]
+    [DataRow("client_secret:secret_value", "client_secret: [REDACTED]")]
+    public void SecretKeyValueRules_ShouldSupportColonSeparator(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("password = secret123", "password= [REDACTED]")]
+    [DataRow("api key  =  api_key_value", "api key= [REDACTED]")]
+    [DataRow("token : token_value", "token: [REDACTED]")]
+    public void SecretKeyValueRules_ShouldHandleWhitespace(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("password=secret API_KEY=key config=myConfig", "password= [REDACTED] API_KEY= [REDACTED] config=myConfig")]
+    [DataRow("client_id=id123 name=admin pwd=pass123", "client_id= [REDACTED] name=admin pwd= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldHandleMultipleKeyValuePairsInSingleString(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+
+    [DataTestMethod]
+    [DataRow("cosmos db key=cosmos_key", "cosmos db key= [REDACTED]")]
+    [DataRow("service principal secret=sp_secret", "service principal secret= [REDACTED]")]
+    [DataRow("shared access signature=sas_signature", "shared access signature= [REDACTED]")]
+    public void SecretKeyValueRules_ShouldMaskServiceSpecificSecrets(string input, string expected)
+    {
+        // Arrange
+        var provider = new SecretKeyValueRulesProvider();
+
+        // Act
+        var result = SanitizerTestHelper.ApplyRules(input, provider.GetRules());
+
+        // Assert
+        Assert.AreEqual(expected, result);
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CmdPal.Core.Common.UnitTests/TestUtils/SanitizerTestHelper.cs

@@ -0,0 +1,110 @@
+// 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.Text.RegularExpressions;
+using Microsoft.CmdPal.Core.Common.Services.Sanitizer.Abstraction;
+
+namespace Microsoft.CmdPal.Common.UnitTests.TestUtils;
+
+/// <summary>
+/// Test-only helpers for applying SanitizationRule sets without relying on production ITextSanitizer implementation.
+/// </summary>
+public static class SanitizerTestHelper
+{
+    /// <summary>
+    /// Applies the provided rules to the input, in order, mimicking the production sanitizer behavior closely
+    /// but without any external dependencies.
+    /// </summary>
+    public static string ApplyRules(string? input, IEnumerable<SanitizationRule> rules)
+    {
+        if (string.IsNullOrEmpty(input))
+        {
+            return input ?? string.Empty;
+        }
+
+        var result = input;
+        foreach (var rule in rules ?? [])
+        {
+            try
+            {
+                var previous = result;
+                result = rule.Evaluator is null
+                    ? rule.Regex.Replace(previous, rule.Replacement ?? string.Empty)
+                    : rule.Regex.Replace(previous, rule.Evaluator);
+
+                // Guardrail to avoid accidental mass-redaction from a faulty rule
+                if (result.Length < previous.Length * 0.3)
+                {
+                    result = previous;
+                }
+            }
+            catch (RegexMatchTimeoutException)
+            {
+                // Ignore timeouts in tests
+            }
+        }
+
+        return result;
+    }
+
+    /// <summary>
+    /// Creates a lightweight sanitizer instance backed by the given rules.
+    /// Useful when a component expects an ITextSanitizer, but you want deterministic behavior in tests.
+    /// </summary>
+    public static ITextSanitizer CreateSanitizer(IEnumerable<SanitizationRule> rules)
+        => new InlineSanitizer(rules);
+
+    private sealed class InlineSanitizer : ITextSanitizer
+    {
+        private readonly List<SanitizationRule> _rules;
+
+        public InlineSanitizer(IEnumerable<SanitizationRule> rules)
+        {
+            _rules = rules?.ToList() ?? [];
+        }
+
+        public string Sanitize(string? input) => ApplyRules(input, _rules);
+
+        public void AddRule(string pattern, string replacement, string description = "")
+        {
+            var rx = new Regex(pattern, RegexOptions.Compiled | RegexOptions.CultureInvariant);
+            _rules.Add(new SanitizationRule(rx, replacement, description));
+        }
+
+        public void RemoveRule(string description)
+        {
+            _rules.RemoveAll(r => r.Description.Equals(description, StringComparison.OrdinalIgnoreCase));
+        }
+
+        public IReadOnlyList<SanitizationRule> GetRules() => _rules.AsReadOnly();
+
+        public string TestRule(string input, string ruleDescription)
+        {
+            var rule = _rules.FirstOrDefault(r => r.Description.Contains(ruleDescription, StringComparison.OrdinalIgnoreCase));
+            if (rule.Regex is null)
+            {
+                return input;
+            }
+
+            try
+            {
+                if (rule.Evaluator is not null)
+                {
+                    return rule.Regex.Replace(input, rule.Evaluator);
+                }
+
+                if (rule.Replacement is not null)
+                {
+                    return rule.Regex.Replace(input, rule.Replacement);
+                }
+            }
+            catch
+            {
+                // Ignore exceptions for test determinism
+            }
+
+            return input;
+        }
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CmdPal.Ext.Calc.UnitTests/CloseOnEnterTests.cs

@@ -19,6 +19,7 @@ public class CloseOnEnterTests
     {
         var settings = new Settings(closeOnEnter: true);
         TypedEventHandler<object, object> handleSave = (s, e) => { };
+        TypedEventHandler<object, object> handleReplace = (s, e) => { };
 
         var item = ResultHelper.CreateResult(
             4m,
@@ -26,7 +27,8 @@ public class CloseOnEnterTests
             CultureInfo.CurrentCulture,
             "2+2",
             settings,
-            handleSave);
+            handleSave,
+            handleReplace);
 
         Assert.IsNotNull(item);
         Assert.IsInstanceOfType(item.Command, typeof(CopyTextCommand));
@@ -41,6 +43,7 @@ public class CloseOnEnterTests
     {
         var settings = new Settings(closeOnEnter: false);
         TypedEventHandler<object, object> handleSave = (s, e) => { };
+        TypedEventHandler<object, object> handleReplace = (s, e) => { };
 
         var item = ResultHelper.CreateResult(
             4m,
@@ -48,7 +51,8 @@ public class CloseOnEnterTests
             CultureInfo.CurrentCulture,
             "2+2",
             settings,
-            handleSave);
+            handleSave,
+            handleReplace);
 
         Assert.IsNotNull(item);
         Assert.IsInstanceOfType(item.Command, typeof(SaveCommand));

src/modules/cmdpal/Tests/Microsoft.CmdPal.Ext.Calc.UnitTests/ExtendedCalculatorParserTests.cs

@@ -65,6 +65,9 @@ public class ExtendedCalculatorParserTests : CommandPaletteUnitTestBase
             ["log10(3)", 0.47712125471966M],
             ["ln(e)", 1M],
             ["cosh(0)", 1M],
+            ["1*10^(-5)", 0.00001M],
+            ["1*10^(-15)", 0.0000000000000001M],
+            ["1*10^(-16)", 0M],
         ];
 
     [DataTestMethod]
@@ -192,9 +195,11 @@ public class ExtendedCalculatorParserTests : CommandPaletteUnitTestBase
     private static IEnumerable<object[]> Interpret_MustReturnExpectedResult_WhenCalled_Data =>
         [
 
-            // ["factorial(5)", 120M], ToDo: this don't support now
-            // ["sign(-2)", -1M],
-            // ["sign(2)", +1M],
+            ["factorial(5)", 120M],
+            ["5!", 120M],
+            ["(2+3)!", 120M],
+            ["sign(-2)", -1M],
+            ["sign(2)", +1M],
             ["abs(-2)", 2M],
             ["abs(2)", 2M],
             ["0+(1*2)/(0+1)", 2M], // Validate that division by "(0+1)" is not interpret as division by zero.
@@ -221,6 +226,9 @@ public class ExtendedCalculatorParserTests : CommandPaletteUnitTestBase
         [
             ["0.2E1", "en-US", 2M],
             ["0,2E1", "pt-PT", 2M],
+            ["3.5e3 + 2.5E2", "en-US", 3750M],
+            ["3,5e3 + 2,5E2", "fr-FR", 3750M],
+            ["1E3-1E3/1.5", "en-US", 333.333333333333371M],
         ];
 
     [DataTestMethod]
@@ -389,4 +397,17 @@ public class ExtendedCalculatorParserTests : CommandPaletteUnitTestBase
         Assert.IsNotNull(result);
         Assert.AreEqual(expectedResult, result);
     }
+
+    [DataTestMethod]
+    [DataRow("171!")]
+    [DataRow("1000!")]
+    public void Interpret_ReturnsError_WhenValueOverflowsDecimal(string input)
+    {
+        var settings = new Settings();
+
+        CalculateEngine.Interpret(settings, input, CultureInfo.InvariantCulture, out var error);
+
+        Assert.IsFalse(string.IsNullOrEmpty(error));
+        Assert.AreNotEqual(null, error);
+    }
 }

src/modules/cmdpal/Tests/Microsoft.CmdPal.Ext.Calc.UnitTests/IncompleteQueryTests.cs

@@ -0,0 +1,38 @@
+// 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 Microsoft.CmdPal.Ext.Calc.Helper;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Microsoft.CmdPal.Ext.Calc.UnitTests;
+
+[TestClass]
+public class IncompleteQueryTests
+{
+    [DataTestMethod]
+    [DataRow("2+2+", "2+2")]
+    [DataRow("2+2*", "2+2")]
+    [DataRow("sin(30", "sin(30)")]
+    [DataRow("((1+2)", "((1+2))")]
+    [DataRow("2*(3+4", "2*(3+4)")]
+    [DataRow("(1+2", "(1+2)")]
+    [DataRow("2*(", "2")]
+    [DataRow("2*(((", "2")]
+    public void TestTryGetIncompleteQuerySuccess(string input, string expected)
+    {
+        var result = QueryHelper.TryGetIncompleteQuery(input, out var newQuery);
+        Assert.IsTrue(result);
+        Assert.AreEqual(expected, newQuery);
+    }
+
+    [DataTestMethod]
+    [DataRow("")]
+    [DataRow("   ")]
+    public void TestTryGetIncompleteQueryFail(string input)
+    {
+        var result = QueryHelper.TryGetIncompleteQuery(input, out var newQuery);
+        Assert.IsFalse(result);
+        Assert.AreEqual(input, newQuery);
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CmdPal.Ext.Calc.UnitTests/QueryHelperTests.cs

@@ -0,0 +1,27 @@
+// 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 Microsoft.CmdPal.Ext.Calc.Helper;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Microsoft.CmdPal.Ext.Calc.UnitTests;
+
+[TestClass]
+public class QueryHelperTests
+{
+    [DataTestMethod]
+    [DataRow("2²", "4")]
+    [DataRow("2³", "8")]
+    [DataRow("2！", "2")]
+    [DataRow("2\u00A0*\u00A02", "4")] // Non-breaking space
+    [DataRow("20:10", "2")] // Colon as division
+    public void Interpret_HandlesNormalizedInputs(string input, string expected)
+    {
+        var settings = new Settings();
+        var result = QueryHelper.Query(input, settings, false, out _, (_, _) => { });
+
+        Assert.IsNotNull(result);
+        Assert.AreEqual(expected, result.Title);
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CmdPal.Ext.Calc.UnitTests/QueryTests.cs

@@ -6,7 +6,6 @@ using System.Linq;
 using Microsoft.CmdPal.Ext.Calc.Helper;
 using Microsoft.CmdPal.Ext.Calc.Pages;
 using Microsoft.CmdPal.Ext.UnitTestBase;
-using Microsoft.CommandPalette.Extensions.Toolkit;
 using Microsoft.VisualStudio.TestTools.UnitTesting;
 
 namespace Microsoft.CmdPal.Ext.Calc.UnitTests;
@@ -72,7 +71,7 @@ public class QueryTests : CommandPaletteUnitTestBase
     [DataRow("sin(60)", "0.809016", CalculateEngine.TrigMode.Gradians)]
     public void TrigModeSettingsTest(string input, string expected, CalculateEngine.TrigMode trigMode)
     {
-        var settings = new Settings(trigUnit: trigMode);
+        var settings = new Settings(trigUnit: trigMode, outputUseEnglishFormat: true);
 
         var page = new CalculatorListPage(settings);
 

src/modules/cmdpal/Tests/Microsoft.CmdPal.Ext.Calc.UnitTests/Settings.cs

@@ -12,17 +12,26 @@ public class Settings : ISettingsInterface
     private readonly bool inputUseEnglishFormat;
     private readonly bool outputUseEnglishFormat;
     private readonly bool closeOnEnter;
+    private readonly bool copyResultToSearchBarIfQueryEndsWithEqualSign;
+    private readonly bool autoFixQuery;
+    private readonly bool inputNormalization;
 
     public Settings(
         CalculateEngine.TrigMode trigUnit = CalculateEngine.TrigMode.Radians,
         bool inputUseEnglishFormat = false,
         bool outputUseEnglishFormat = false,
-        bool closeOnEnter = true)
+        bool closeOnEnter = true,
+        bool copyResultToSearchBarIfQueryEndsWithEqualSign = true,
+        bool autoFixQuery = true,
+        bool inputNormalization = true)
     {
         this.trigUnit = trigUnit;
         this.inputUseEnglishFormat = inputUseEnglishFormat;
         this.outputUseEnglishFormat = outputUseEnglishFormat;
         this.closeOnEnter = closeOnEnter;
+        this.copyResultToSearchBarIfQueryEndsWithEqualSign = copyResultToSearchBarIfQueryEndsWithEqualSign;
+        this.autoFixQuery = autoFixQuery;
+        this.inputNormalization = inputNormalization;
     }
 
     public CalculateEngine.TrigMode TrigUnit => trigUnit;
@@ -32,4 +41,10 @@ public class Settings : ISettingsInterface
     public bool OutputUseEnglishFormat => outputUseEnglishFormat;
 
     public bool CloseOnEnter => closeOnEnter;
+
+    public bool CopyResultToSearchBarIfQueryEndsWithEqualSign => copyResultToSearchBarIfQueryEndsWithEqualSign;
+
+    public bool AutoFixQuery => autoFixQuery;
+
+    public bool InputNormalization => inputNormalization;
 }

src/modules/cmdpal/Tests/Microsoft.CommandPalette.Extensions.Toolkit.UnitTests/FuzzyMatcherComparisonTests.cs

@@ -0,0 +1,235 @@
+// 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.Collections.Generic;
+using Microsoft.CommandPalette.Extensions.Toolkit.UnitTests.Legacy;
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Microsoft.CommandPalette.Extensions.Toolkit.UnitTests;
+
+[TestClass]
+public class FuzzyMatcherComparisonTests
+{
+    public static IEnumerable<object[]> TestData =>
+        [
+            ["a", "a"],
+            ["a", "A"],
+            ["A", "a"],
+            ["abc", "abc"],
+            ["abc", "axbycz"],
+            ["abc", "abxcyz"],
+            ["sln", "solution.sln"],
+            ["vs", "visualstudio"],
+            ["test", "Test"],
+            ["pt", "PowerToys"],
+            ["p/t", "power\\toys"],
+            ["p\\t", "power/toys"],
+            ["c/w", "c:\\windows"],
+            ["foo", "bar"],
+            ["verylongstringthatdoesnotmatch", "short"],
+            [string.Empty, "anything"],
+            ["something", string.Empty],
+            ["git", "git"],
+            ["em", "Emmy"],
+            ["my", "Emmy"],
+            ["word", "word"],
+            ["wd", "word"],
+            ["w d", "word"],
+            ["a", "ba"],
+            ["a", "ab"],
+            ["a", "bab"],
+            ["z", "abcdefg"],
+            ["CC", "CamelCase"],
+            ["cc", "camelCase"],
+            ["cC", "camelCase"],
+            ["some", "awesome"],
+            ["some", "somewhere"],
+            ["1", "1"],
+            ["1", "2"],
+            [".", "."],
+            ["f.t", "file.txt"],
+            ["excel", "Excel"],
+            ["Excel", "excel"],
+            ["PowerPoint", "Power Point"],
+            ["power point", "PowerPoint"],
+            ["visual studio code", "Visual Studio Code"],
+            ["vsc", "Visual Studio Code"],
+            ["code", "Visual Studio Code"],
+            ["vs code", "Visual Studio Code"],
+            ["word", "Microsoft Word"],
+            ["ms word", "Microsoft Word"],
+            ["browser", "Internet Explorer"],
+            ["chrome", "Google Chrome"],
+            ["edge", "Microsoft Edge"],
+            ["term", "Windows Terminal"],
+            ["cmd", "Command Prompt"],
+            ["calc", "Calculator"],
+            ["snipping", "Snipping Tool"],
+            ["note", "Notepad"],
+            ["file expl", "File Explorer"],
+            ["settings", "Settings"],
+            ["p t", "PowerToys"],
+            ["p  t", "PowerToys"],
+            [" v ", " Visual Studio "],
+            [" a b ", " a b c d "],
+            [string.Empty, string.Empty],
+            [" ", " "],
+            ["   ", " "],
+            [" ", "abc"],
+            ["abc", " "],
+            ["   ", "   "],
+            [" ", " a b "],
+            ["sh", "ShangHai"],
+            ["bj", "BeiJing"],
+            ["bj", "北京"],
+            ["sh", "上海"],
+            ["nh", "你好"],
+            ["bj", "Beijing"],
+            ["hello", "你好"],
+            ["nihao", "你好"],
+            ["rmb", "人民币"],
+            ["zwr", "中文"],
+            ["zw", "中文"],
+            ["fbr", "foobar"],
+            ["w11", "windows 11"],
+            ["pwr", "powershell"],
+            ["vm", "void main"],
+            ["ps", "PowerShell"],
+            ["az", "Azure"],
+            ["od", "onedrive"],
+            ["gc", "google chrome"],
+            ["ff", "firefox"],
+            ["fs", "file_system"],
+            ["pt", "power-toys"],
+            ["jt", "json.test"],
+            ["ps", "power shell"],
+            ["ps", "power'shell"],
+            ["ps", "power\"shell"],
+            ["hw", "hello:world"],
+            ["abc", "a_b_c"],
+            ["abc", "a-b-c"],
+            ["abc", "a.b.c"],
+            ["abc", "a b c"],
+            ["abc", "a'b'c"],
+            ["abc", "a\"b\"c"],
+            ["abc", "a:b:c"],
+            ["_a", "_a"],
+            ["a_", "a_"],
+            ["-a", "-a"],
+            ["a-", "a-"]
+        ];
+
+    [TestMethod]
+    [DynamicData(nameof(TestData))]
+    public void CompareScores(string needle, string haystack)
+    {
+        var legacyScore = LegacyFuzzyStringMatcher.ScoreFuzzy(needle, haystack);
+        var newScore = FuzzyStringMatcher.ScoreFuzzy(needle, haystack);
+
+        Assert.AreEqual(legacyScore, newScore, $"Score mismatch for needle='{needle}', haystack='{haystack}'");
+    }
+
+    [TestMethod]
+    [DynamicData(nameof(TestData))]
+    public void ComparePositions(string needle, string haystack)
+    {
+        var (legacyScore, legacyPos) = LegacyFuzzyStringMatcher.ScoreFuzzyWithPositions(needle, haystack, true);
+        var (newScore, newPos) = FuzzyStringMatcher.ScoreFuzzyWithPositions(needle, haystack, true);
+
+        Assert.AreEqual(legacyScore, newScore, $"Score mismatch (with pos) for needle='{needle}', haystack='{haystack}'");
+
+        // Ensure lists are not null
+        legacyPos ??= [];
+        newPos ??= [];
+
+        // Compare list contents
+        var legacyPosStr = string.Join(',', legacyPos);
+        var newPosStr = string.Join(',', newPos);
+
+        Assert.AreEqual(legacyPos.Count, newPos.Count, $"Position count mismatch: Legacy=[{legacyPosStr}], New=[{newPosStr}]");
+
+        for (var i = 0; i < legacyPos.Count; i++)
+        {
+            Assert.AreEqual(legacyPos[i], newPos[i], $"Position mismatch at index {i}: Legacy=[{legacyPosStr}], New=[{newPosStr}]");
+        }
+    }
+
+    [TestMethod]
+    [DynamicData(nameof(TestData))]
+    public void CompareScores_ContiguousOnly(string needle, string haystack)
+    {
+        var legacyScore = LegacyFuzzyStringMatcher.ScoreFuzzy(needle, haystack, allowNonContiguousMatches: false);
+        var newScore = FuzzyStringMatcher.ScoreFuzzy(needle, haystack, allowNonContiguousMatches: false);
+
+        Assert.AreEqual(legacyScore, newScore, $"Score mismatch (contiguous only) for needle='{needle}', haystack='{haystack}'");
+    }
+
+    [TestMethod]
+    [DynamicData(nameof(TestData))]
+    public void CompareScores_PinyinEnabled(string needle, string haystack)
+    {
+        var originalNew = FuzzyStringMatcher.ChinesePinYinSupport;
+        var originalLegacy = LegacyFuzzyStringMatcher.ChinesePinYinSupport;
+        try
+        {
+            FuzzyStringMatcher.ChinesePinYinSupport = true;
+            LegacyFuzzyStringMatcher.ChinesePinYinSupport = true;
+
+            var legacyScore = LegacyFuzzyStringMatcher.ScoreFuzzy(needle, haystack);
+            var newScore = FuzzyStringMatcher.ScoreFuzzy(needle, haystack);
+
+            Assert.AreEqual(legacyScore, newScore, $"Score mismatch (Pinyin enabled) for needle='{needle}', haystack='{haystack}'");
+        }
+        finally
+        {
+            FuzzyStringMatcher.ChinesePinYinSupport = originalNew;
+            LegacyFuzzyStringMatcher.ChinesePinYinSupport = originalLegacy;
+        }
+    }
+
+    [TestMethod]
+    [DynamicData(nameof(TestData))]
+    public void ComparePositions_PinyinEnabled(string needle, string haystack)
+    {
+        var originalNew = FuzzyStringMatcher.ChinesePinYinSupport;
+        var originalLegacy = LegacyFuzzyStringMatcher.ChinesePinYinSupport;
+        try
+        {
+            FuzzyStringMatcher.ChinesePinYinSupport = true;
+            LegacyFuzzyStringMatcher.ChinesePinYinSupport = true;
+
+            var (legacyScore, legacyPos) = LegacyFuzzyStringMatcher.ScoreFuzzyWithPositions(needle, haystack, true);
+            var (newScore, newPos) = FuzzyStringMatcher.ScoreFuzzyWithPositions(needle, haystack, true);
+
+            Assert.AreEqual(legacyScore, newScore, $"Score mismatch (with pos, Pinyin enabled) for needle='{needle}', haystack='{haystack}'");
+
+            // Ensure lists are not null
+            legacyPos ??= [];
+            newPos ??= [];
+
+            // If newPos is empty but newScore > 0, it means it's a secondary match (like Pinyin)
+            // which we don't return positions for in the new matcher.
+            if (newScore > 0 && newPos.Count == 0 && legacyPos.Count > 0)
+            {
+                return;
+            }
+
+            // Compare list contents
+            var legacyPosStr = string.Join(',', legacyPos);
+            var newPosStr = string.Join(',', newPos);
+
+            Assert.AreEqual(legacyPos.Count, newPos.Count, $"Position count mismatch: Legacy=[{legacyPosStr}], New=[{newPosStr}]");
+
+            for (var i = 0; i < legacyPos.Count; i++)
+            {
+                Assert.AreEqual(legacyPos[i], newPos[i], $"Position mismatch at index {i}: Legacy=[{legacyPosStr}], New=[{newPosStr}]");
+            }
+        }
+        finally
+        {
+            FuzzyStringMatcher.ChinesePinYinSupport = originalNew;
+            LegacyFuzzyStringMatcher.ChinesePinYinSupport = originalLegacy;
+        }
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CommandPalette.Extensions.Toolkit.UnitTests/FuzzyMatcherDiacriticsTests.cs

@@ -0,0 +1,85 @@
+// 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 Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Microsoft.CommandPalette.Extensions.Toolkit.UnitTests;
+
+[TestClass]
+public class FuzzyMatcherDiacriticsTests
+{
+    [TestMethod]
+    public void ScoreFuzzy_WithDiacriticsRemoval_MatchesWithDiacritics()
+    {
+        // "eco" should match "école" when diacritics are removed (é -> E)
+        var score = FuzzyStringMatcher.ScoreFuzzy("eco", "école", allowNonContiguousMatches: true, removeDiacritics: true);
+        Assert.IsTrue(score > 0, "Should match 'école' with 'eco' when diacritics are removed");
+
+        // "uber" should match "über"
+        score = FuzzyStringMatcher.ScoreFuzzy("uber", "über", allowNonContiguousMatches: true, removeDiacritics: true);
+        Assert.IsTrue(score > 0, "Should match 'über' with 'uber' when diacritics are removed");
+    }
+
+    [TestMethod]
+    public void ScoreFuzzy_WithoutDiacriticsRemoval_DoesNotMatchWhenCharactersDiffer()
+    {
+        // "eco" should NOT match "école" if 'é' is treated as distinct from 'e' and order is strict
+        // 'é' (index 0) != 'e'. 'e' (index 4) is after 'c' (index 1) and 'o' (index 2).
+        // Since needle is "e-c-o", to match "école":
+        // 'e' matches 'e' at 4.
+        // 'c' must show up after. No.
+        // So no match.
+        var score = FuzzyStringMatcher.ScoreFuzzy("eco", "école", allowNonContiguousMatches: true, removeDiacritics: false);
+        Assert.AreEqual(0, score, "Should not match 'école' with 'eco' when diacritics are NOT removed");
+
+        // "uber" vs "über"
+        // u != ü.
+        // b (index 1) match b (index 2). e (2) match e (3). r (3) match r (4).
+        // but 'u' has no match.
+        score = FuzzyStringMatcher.ScoreFuzzy("uber", "über", allowNonContiguousMatches: true, removeDiacritics: false);
+        Assert.AreEqual(0, score, "Should not match 'über' with 'uber' when diacritics are NOT removed");
+    }
+
+    [TestMethod]
+    public void ScoreFuzzy_DefaultRemovesDiacritics()
+    {
+        // Now default is true, so "eco" vs "école" should match
+        var score = FuzzyStringMatcher.ScoreFuzzy("eco", "école");
+        Assert.IsTrue(score > 0, "Default should remove diacritics and match 'école'");
+    }
+
+    [DataTestMethod]
+    [DataRow("a", "à", true)]
+    [DataRow("e", "é", true)]
+    [DataRow("i", "ï", true)]
+    [DataRow("o", "ô", true)]
+    [DataRow("u", "ü", true)]
+    [DataRow("c", "ç", true)]
+    [DataRow("n", "ñ", true)]
+    [DataRow("s", "ß", false)] // ß doesn't strip to s via simple invalid-uppercasing
+    public void VerifySpecificCharacters(string needle, string haystack, bool expectingMatch)
+    {
+        var score = FuzzyStringMatcher.ScoreFuzzy(needle, haystack, allowNonContiguousMatches: true, removeDiacritics: true);
+        if (expectingMatch)
+        {
+            Assert.IsTrue(score > 0, $"Expected match for '{needle}' in '{haystack}' with diacritics removal");
+        }
+        else
+        {
+            Assert.AreEqual(0, score, $"Expected NO match for '{needle}' in '{haystack}' even with diacritics removal");
+        }
+    }
+
+    [TestMethod]
+    public void VerifyBothPathsWorkSameForASCII()
+    {
+        var needle = "test";
+        var haystack = "TestString";
+
+        var score1 = FuzzyStringMatcher.ScoreFuzzy(needle, haystack, allowNonContiguousMatches: true, removeDiacritics: true);
+        var score2 = FuzzyStringMatcher.ScoreFuzzy(needle, haystack, allowNonContiguousMatches: true, removeDiacritics: false);
+
+        Assert.AreEqual(score1, score2, "Scores should be identical for ASCII strings regardless of diacritics setting");
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CommandPalette.Extensions.Toolkit.UnitTests/FuzzyMatcherPinyinLogicTests.cs

@@ -0,0 +1,46 @@
+// 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 Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Microsoft.CommandPalette.Extensions.Toolkit.UnitTests;
+
+[TestClass]
+public class FuzzyMatcherPinyinLogicTests
+{
+    [TestInitialize]
+    public void Setup()
+    {
+        FuzzyStringMatcher.ChinesePinYinSupport = true;
+        FuzzyStringMatcher.ClearCache();
+    }
+
+    [TestCleanup]
+    public void Cleanup()
+    {
+        FuzzyStringMatcher.ChinesePinYinSupport = false; // Reset to default state
+        FuzzyStringMatcher.ClearCache();
+    }
+
+    [DataTestMethod]
+    [DataRow("bj", "北京")]
+    [DataRow("sh", "上海")]
+    [DataRow("nihao", "你好")]
+    [DataRow("北京", "北京")]
+    [DataRow("北京", "Beijing")]
+    [DataRow("北", "北京")]
+    [DataRow("你好", "nihao")]
+    public void PinyinMatch_DataDriven(string needle, string haystack)
+    {
+        Assert.IsTrue(FuzzyStringMatcher.ScoreFuzzy(needle, haystack) > 0, $"Expected match for '{needle}' in '{haystack}'");
+    }
+
+    [TestMethod]
+    public void PinyinPositions_ShouldBeEmpty()
+    {
+        var (score, positions) = FuzzyStringMatcher.ScoreFuzzyWithPositions("bj", "北京", true);
+        Assert.IsTrue(score > 0);
+        Assert.AreEqual(0, positions.Count);
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CommandPalette.Extensions.Toolkit.UnitTests/FuzzyMatcherValidationTests.cs

@@ -0,0 +1,43 @@
+// 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 Microsoft.VisualStudio.TestTools.UnitTesting;
+
+namespace Microsoft.CommandPalette.Extensions.Toolkit.UnitTests;
+
+[TestClass]
+public class FuzzyMatcherValidationTests
+{
+    [DataTestMethod]
+    [DataRow(null, "haystack")]
+    [DataRow("", "haystack")]
+    [DataRow("needle", null)]
+    [DataRow("needle", "")]
+    [DataRow(null, null)]
+    public void ScoreFuzzy_HandlesIncorrectInputs(string needle, string haystack)
+    {
+        Assert.AreEqual(0, FuzzyStringMatcher.ScoreFuzzy(needle!, haystack!));
+        Assert.AreEqual(0, FuzzyStringMatcher.ScoreFuzzy(needle!, haystack!, allowNonContiguousMatches: true, removeDiacritics: true));
+        Assert.AreEqual(0, FuzzyStringMatcher.ScoreFuzzy(needle!, haystack!, allowNonContiguousMatches: false, removeDiacritics: false));
+    }
+
+    [DataTestMethod]
+    [DataRow(null, "haystack")]
+    [DataRow("", "haystack")]
+    [DataRow("needle", null)]
+    [DataRow("needle", "")]
+    [DataRow(null, null)]
+    public void ScoreFuzzyWithPositions_HandlesIncorrectInputs(string needle, string haystack)
+    {
+        var (score1, pos1) = FuzzyStringMatcher.ScoreFuzzyWithPositions(needle!, haystack!, true);
+        Assert.AreEqual(0, score1);
+        Assert.IsNotNull(pos1);
+        Assert.AreEqual(0, pos1.Count);
+
+        var (score2, pos2) = FuzzyStringMatcher.ScoreFuzzyWithPositions(needle!, haystack!, allowNonContiguousMatches: true, removeDiacritics: true);
+        Assert.AreEqual(0, score2);
+        Assert.IsNotNull(pos2);
+        Assert.AreEqual(0, pos2.Count);
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CommandPalette.Extensions.Toolkit.UnitTests/Legacy/LegacyFuzzyStringMatcher.cs

@@ -0,0 +1,225 @@
+// 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;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using ToolGood.Words.Pinyin;
+
+namespace Microsoft.CommandPalette.Extensions.Toolkit.UnitTests.Legacy;
+
+// Inspired by the fuzzy.rs from edit.exe
+public static class LegacyFuzzyStringMatcher
+{
+    private const int NOMATCH = 0;
+
+    /// <summary>
+    /// Gets or sets a value indicating whether to support Chinese PinYin.
+    /// Automatically enabled when the system UI culture is Simplified Chinese.
+    /// </summary>
+    public static bool ChinesePinYinSupport { get; set; } = IsSimplifiedChinese();
+
+    private static bool IsSimplifiedChinese()
+    {
+        var culture = CultureInfo.CurrentUICulture;
+
+        // Detect Simplified Chinese: zh-CN, zh-Hans, zh-Hans-*
+        return culture.Name.StartsWith("zh-CN", StringComparison.OrdinalIgnoreCase)
+            || culture.Name.StartsWith("zh-Hans", StringComparison.OrdinalIgnoreCase);
+    }
+
+    public static int ScoreFuzzy(string needle, string haystack, bool allowNonContiguousMatches = true)
+    {
+        var (s, _) = ScoreFuzzyWithPositions(needle, haystack, allowNonContiguousMatches);
+        return s;
+    }
+
+    public static (int Score, List<int> Positions) ScoreFuzzyWithPositions(string needle, string haystack, bool allowNonContiguousMatches)
+        => ScoreAllFuzzyWithPositions(needle, haystack, allowNonContiguousMatches).MaxBy(i => i.Score);
+
+    public static IEnumerable<(int Score, List<int> Positions)> ScoreAllFuzzyWithPositions(string needle, string haystack, bool allowNonContiguousMatches)
+    {
+        List<string> needles = [needle];
+        List<string> haystacks = [haystack];
+
+        if (ChinesePinYinSupport)
+        {
+            // Remove IME composition split characters.
+            var input = needle.Replace("'", string.Empty);
+            needles.Add(WordsHelper.GetPinyin(input));
+            if (WordsHelper.HasChinese(haystack))
+            {
+                haystacks.Add(WordsHelper.GetPinyin(haystack));
+            }
+        }
+
+        return needles.SelectMany(i => haystacks.Select(j => ScoreFuzzyWithPositionsInternal(i, j, allowNonContiguousMatches)));
+    }
+
+    private static (int Score, List<int> Positions) ScoreFuzzyWithPositionsInternal(string needle, string haystack, bool allowNonContiguousMatches)
+    {
+        if (string.IsNullOrEmpty(haystack) || string.IsNullOrEmpty(needle))
+        {
+            return (NOMATCH, new List<int>());
+        }
+
+        var target = haystack.ToCharArray();
+        var query = needle.ToCharArray();
+
+        if (target.Length < query.Length)
+        {
+            return (NOMATCH, new List<int>());
+        }
+
+        var targetUpper = FoldCase(haystack);
+        var queryUpper = FoldCase(needle);
+        var targetUpperChars = targetUpper.ToCharArray();
+        var queryUpperChars = queryUpper.ToCharArray();
+
+        var area = query.Length * target.Length;
+        var scores = new int[area];
+        var matches = new int[area];
+
+        for (var qi = 0; qi < query.Length; qi++)
+        {
+            var qiOffset = qi * target.Length;
+            var qiPrevOffset = qi > 0 ? (qi - 1) * target.Length : 0;
+
+            for (var ti = 0; ti < target.Length; ti++)
+            {
+                var currentIndex = qiOffset + ti;
+                var diagIndex = (qi > 0 && ti > 0) ? qiPrevOffset + ti - 1 : 0;
+                var leftScore = ti > 0 ? scores[currentIndex - 1] : 0;
+                var diagScore = (qi > 0 && ti > 0) ? scores[diagIndex] : 0;
+                var matchSeqLen = (qi > 0 && ti > 0) ? matches[diagIndex] : 0;
+
+                var score = (diagScore == 0 && qi != 0) ? 0 :
+                    ComputeCharScore(
+                        query[qi],
+                        queryUpperChars[qi],
+                        ti != 0 ? target[ti - 1] : null,
+                        target[ti],
+                        targetUpperChars[ti],
+                        matchSeqLen);
+
+                var isValidScore = score != 0 && diagScore + score >= leftScore &&
+                    (allowNonContiguousMatches || qi > 0 ||
+                     targetUpperChars.Skip(ti).Take(queryUpperChars.Length).SequenceEqual(queryUpperChars));
+
+                if (isValidScore)
+                {
+                    matches[currentIndex] = matchSeqLen + 1;
+                    scores[currentIndex] = diagScore + score;
+                }
+                else
+                {
+                    matches[currentIndex] = NOMATCH;
+                    scores[currentIndex] = leftScore;
+                }
+            }
+        }
+
+        var positions = new List<int>();
+        if (query.Length > 0 && target.Length > 0)
+        {
+            var qi = query.Length - 1;
+            var ti = target.Length - 1;
+
+            while (true)
+            {
+                var index = (qi * target.Length) + ti;
+                if (matches[index] == NOMATCH)
+                {
+                    if (ti == 0)
+                    {
+                        break;
+                    }
+
+                    ti--;
+                }
+                else
+                {
+                    positions.Add(ti);
+                    if (qi == 0 || ti == 0)
+                    {
+                        break;
+                    }
+
+                    qi--;
+                    ti--;
+                }
+            }
+
+            positions.Reverse();
+        }
+
+        return (scores[area - 1], positions);
+    }
+
+    private static string FoldCase(string input)
+    {
+        return input.ToUpperInvariant();
+    }
+
+    private static int ComputeCharScore(
+        char query,
+        char queryLower,
+        char? targetPrev,
+        char targetCurr,
+        char targetLower,
+        int matchSeqLen)
+    {
+        if (!ConsiderAsEqual(queryLower, targetLower))
+        {
+            return 0;
+        }
+
+        var score = 1; // Character match bonus
+
+        if (matchSeqLen > 0)
+        {
+            score += matchSeqLen * 5; // Consecutive match bonus
+        }
+
+        if (query == targetCurr)
+        {
+            score += 1; // Same case bonus
+        }
+
+        if (targetPrev.HasValue)
+        {
+            var sepBonus = ScoreSeparator(targetPrev.Value);
+            if (sepBonus > 0)
+            {
+                score += sepBonus;
+            }
+            else if (char.IsUpper(targetCurr) && matchSeqLen == 0)
+            {
+                score += 2; // CamelCase bonus
+            }
+        }
+        else
+        {
+            score += 8; // Start of word bonus
+        }
+
+        return score;
+    }
+
+    private static bool ConsiderAsEqual(char a, char b)
+    {
+        return a == b || (a == '/' && b == '\\') || (a == '\\' && b == '/');
+    }
+
+    private static int ScoreSeparator(char ch)
+    {
+        return ch switch
+        {
+            '/' or '\\' => 5,
+            '_' or '-' or '.' or ' ' or '\'' or '"' or ':' => 4,
+            _ => 0,
+        };
+    }
+}

src/modules/cmdpal/Tests/Microsoft.CommandPalette.Extensions.Toolkit.UnitTests/Microsoft.CommandPalette.Extensions.Toolkit.UnitTests.csproj

@@ -0,0 +1,30 @@
+<Project Sdk="Microsoft.NET.Sdk">
+	<!-- Look at Directory.Build.props in root for common stuff as well -->
+	<Import Project="..\..\..\..\Common.Dotnet.CsWinRT.props" />
+
+	<PropertyGroup>
+		<RepoRoot>$(MSBuildThisFileDirectory)..\..\..\..\..\</RepoRoot>
+		<IsPackable>false</IsPackable>
+		<IsTestProject>true</IsTestProject>
+		<RootNamespace>Microsoft.CommandPalette.Extensions.Toolkit.UnitTests</RootNamespace>
+		<OutputPath>$(SolutionDir)$(Platform)\$(Configuration)\WinUI3Apps\CmdPal\tests\</OutputPath>
+		<AppendTargetFrameworkToOutputPath>false</AppendTargetFrameworkToOutputPath>
+		<AppendRuntimeIdentifierToOutputPath>false</AppendRuntimeIdentifierToOutputPath>
+		<Nullable>enable</Nullable>
+	</PropertyGroup>
+
+	<ItemGroup>
+		<PackageReference Include="Moq" />
+		<PackageReference Include="MSTest" />
+	</ItemGroup>
+
+	<ItemGroup>
+	  <ProjectReference Include="..\..\extensionsdk\Microsoft.CommandPalette.Extensions.Toolkit\Microsoft.CommandPalette.Extensions.Toolkit.csproj" />
+	</ItemGroup>
+
+	<PropertyGroup Condition="'$(CIBuild)'=='true'">
+		<SignAssembly>true</SignAssembly>
+		<DelaySign>true</DelaySign>
+		<AssemblyOriginatorKeyFile>$(RepoRoot).pipelines\272MSSharedLibSN2048.snk</AssemblyOriginatorKeyFile>
+	</PropertyGroup>
+</Project>

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Helper/BracketHelper.cs

@@ -53,6 +53,56 @@ public static class BracketHelper
         return trailTest.Count == 0;
     }
 
+    public static string BalanceBrackets(string query)
+    {
+        if (string.IsNullOrWhiteSpace(query))
+        {
+            return query ?? string.Empty;
+        }
+
+        var openBrackets = new Stack<TrailType>();
+
+        for (var i = 0; i < query.Length; i++)
+        {
+            var (direction, type) = BracketTrail(query[i]);
+
+            if (direction == TrailDirection.None)
+            {
+                continue;
+            }
+
+            if (direction == TrailDirection.Open)
+            {
+                openBrackets.Push(type);
+            }
+            else if (direction == TrailDirection.Close)
+            {
+                // Only pop if we have a matching open bracket
+                if (openBrackets.Count > 0 && openBrackets.Peek() == type)
+                {
+                    openBrackets.Pop();
+                }
+            }
+        }
+
+        if (openBrackets.Count == 0)
+        {
+            return query;
+        }
+
+        // Build closing brackets in LIFO order
+        var closingBrackets = new char[openBrackets.Count];
+        var index = 0;
+
+        while (openBrackets.Count > 0)
+        {
+            var type = openBrackets.Pop();
+            closingBrackets[index++] = type == TrailType.Round ? ')' : ']';
+        }
+
+        return query + new string(closingBrackets);
+    }
+
     private static (TrailDirection Direction, TrailType Type) BracketTrail(char @char)
     {
         switch (@char)

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Helper/CalculateEngine.cs

@@ -1,9 +1,8 @@
-// Copyright (c) Microsoft Corporation
+// 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;
-using System.Collections.Generic;
 using System.Globalization;
 using System.Text.RegularExpressions;
 using CalculatorEngineCommon;
@@ -16,6 +15,7 @@ public static class CalculateEngine
     private static readonly PropertySet _constants = new()
     {
         { "pi", Math.PI },
+        { "π", Math.PI },
         { "e", Math.E },
     };
 
@@ -59,6 +59,8 @@ public static class CalculateEngine
 
         input = CalculateHelper.FixHumanMultiplicationExpressions(input);
 
+        input = CalculateHelper.UpdateFactorialFunctions(input);
+
         // Get the user selected trigonometry unit
         TrigMode trigMode = settings.TrigUnit;
 
@@ -77,6 +79,13 @@ public static class CalculateEngine
             return default;
         }
 
+        // If we're out of bounds
+        if (result is "inf" or "-inf")
+        {
+            error = Properties.Resources.calculator_not_covert_to_decimal;
+            return default;
+        }
+
         if (string.IsNullOrEmpty(result))
         {
             return default;
@@ -110,15 +119,19 @@ public static class CalculateEngine
     /// </summary>
     public static decimal FormatMax15Digits(decimal value, CultureInfo cultureInfo)
     {
+        const int maxDisplayDigits = 15;
+
+        if (value == 0m)
+        {
+            return 0m;
+        }
+
         var absValue = Math.Abs(value);
         var integerDigits = absValue >= 1 ? (int)Math.Floor(Math.Log10((double)absValue)) + 1 : 1;
 
-        var maxDecimalDigits = Math.Max(0, 15 - integerDigits);
+        var maxDecimalDigits = Math.Max(0, maxDisplayDigits - integerDigits);
 
         var rounded = Math.Round(value, maxDecimalDigits, MidpointRounding.AwayFromZero);
-
-        var formatted = rounded.ToString("G29", cultureInfo);
-
-        return Convert.ToDecimal(formatted, cultureInfo);
+        return rounded / 1.000000000000000000000000000000000m;
     }
 }

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Helper/CalculateHelper.cs

@@ -3,11 +3,12 @@
 // See the LICENSE file in the project root for more information.
 
 using System;
+using System.Collections.Generic;
 using System.Text.RegularExpressions;
 
 namespace Microsoft.CmdPal.Ext.Calc.Helper;
 
-public static class CalculateHelper
+public static partial class CalculateHelper
 {
     private static readonly Regex RegValidExpressChar = new Regex(
         @"^(" +
@@ -19,7 +20,7 @@ public static class CalculateHelper
         @"rad\s*\(|deg\s*\(|grad\s*\(|" + /* trigonometry unit conversion macros */
         @"pi|" +
         @"==|~=|&&|\|\||" +
-        @"((-?(\d+(\.\d*)?)|-?(\.\d+))[Ee](-?\d+))|" + /* expression from CheckScientificNotation between parenthesis */
+        @"((\d+(?:\.\d*)?|\.\d+)[eE](-?\d+))|" + /* expression from CheckScientificNotation between parenthesis */
         @"e|[0-9]|0[xX][0-9a-fA-F]+|0[bB][01]+|0[oO][0-7]+|[\+\-\*\/\^\., ""]|[\(\)\|\!\[\]]" +
         @")+$",
         RegexOptions.Compiled);
@@ -31,6 +32,94 @@ public static class CalculateHelper
     private const string RadToDeg = "(180 / pi) * ";
     private const string RadToGrad = "(200 / pi) * ";
 
+    // replacements from the user input to displayed query
+    private static readonly Dictionary<string, string> QueryReplacements = new()
+    {
+        { "％", "%" }, { "﹪", "%" },
+        { "−", "-" }, { "–", "-" }, { "—", "-" },
+        { "！", "!" },
+        { "*", "×" }, { "∗", "×" }, { "·", "×" }, { "⊗", "×" }, { "⋅", "×" }, { "✕", "×" }, { "✖", "×" }, { "\u2062", "×" },
+        { "/", "÷" }, { "∕", "÷" }, { "➗", "÷" }, { ":", "÷" },
+    };
+
+    // replacements from a query to engine input
+    private static readonly Dictionary<string, string> EngineReplacements = new()
+    {
+        { "×", "*" },
+        { "÷", "/" },
+    };
+
+    private static readonly Dictionary<string, string> SuperscriptReplacements = new()
+    {
+        { "²", "^2" }, { "³", "^3" },
+    };
+
+    private static readonly HashSet<char> StandardOperators = [
+
+        // binary operators; doesn't make sense for them to be at the end of a query
+        '+', '-', '*', '/', '%', '^', '=', '&', '|', '\\',
+
+        // parentheses
+        '(', '[',
+    ];
+
+    private static readonly HashSet<char> SuffixOperators = [
+
+        // unary operators; can appear at the end of a query
+        ')', ']', '!',
+    ];
+
+    private static readonly Regex ReplaceScientificNotationRegex = CreateReplaceScientificNotationRegex();
+
+    public static char[] GetQueryOperators()
+    {
+        var ops = new HashSet<char>(StandardOperators);
+        ops.ExceptWith(SuffixOperators);
+        return [.. ops];
+    }
+
+    /// <summary>
+    /// Normalizes the query for display
+    /// This replaces standard operators with more visually appealing ones (e.g., '*' -> '×') if enabled.
+    /// Always applies safe normalizations (standardizing variants like minus, percent, etc.).
+    /// </summary>
+    /// <param name="input">The query string to normalize.</param>
+    public static string NormalizeCharsForDisplayQuery(string input)
+    {
+        // 1. Safe/Trivial replacements (Variant -> Standard)
+        // These are always applied to ensure consistent behavior for non-math symbols (spaces) and
+        // operator variants like minus, percent, and exclamation mark.
+        foreach (var (key, value) in QueryReplacements)
+        {
+            input = input.Replace(key, value);
+        }
+
+        return input;
+    }
+
+    /// <summary>
+    /// Normalizes the query for the calculation engine.
+    /// This replaces all supported operator variants (visual or standard) with the specific
+    /// ASCII operators required by the engine (e.g., '×' -> '*').
+    /// It duplicates and expands upon replacements in NormalizeQuery to ensure the engine
+    /// receives valid input regardless of whether NormalizeQuery was executed.
+    /// </summary>
+    public static string NormalizeCharsToEngine(string input)
+    {
+        foreach (var (key, value) in EngineReplacements)
+        {
+            input = input.Replace(key, value);
+        }
+
+        // Replace superscript characters with their engine equivalents (e.g., '²' -> '^2')
+        foreach (var (key, value) in SuperscriptReplacements)
+        {
+            input = input.Replace(key, value);
+        }
+
+        return input;
+    }
+
     public static bool InputValid(string input)
     {
         if (string.IsNullOrWhiteSpace(input))
@@ -50,7 +139,7 @@ public static class CalculateHelper
 
         // If the input ends with a binary operator then it is not a valid input to mages and the Interpret function would throw an exception. Because we expect here that the user has not finished typing we block those inputs.
         var trimmedInput = input.TrimEnd();
-        if (trimmedInput.EndsWith('+') || trimmedInput.EndsWith('-') || trimmedInput.EndsWith('*') || trimmedInput.EndsWith('|') || trimmedInput.EndsWith('\\') || trimmedInput.EndsWith('^') || trimmedInput.EndsWith('=') || trimmedInput.EndsWith('&') || trimmedInput.EndsWith('/') || trimmedInput.EndsWith('%'))
+        if (EndsWithBinaryOperator(trimmedInput))
         {
             return false;
         }
@@ -58,6 +147,18 @@ public static class CalculateHelper
         return true;
     }
 
+    private static bool EndsWithBinaryOperator(string input)
+    {
+        var operators = GetQueryOperators();
+        if (string.IsNullOrEmpty(input))
+        {
+            return false;
+        }
+
+        var lastChar = input[^1];
+        return Array.Exists(operators, op => op == lastChar);
+    }
+
     public static string FixHumanMultiplicationExpressions(string input)
     {
         var output = CheckScientificNotation(input);
@@ -72,18 +173,7 @@ public static class CalculateHelper
 
     private static string CheckScientificNotation(string input)
     {
-        /**
-         * NOTE: By the time that the expression gets to us, it's already in English format.
-         *
-         * Regex explanation:
-         * (-?(\d+({0}\d*)?)|-?({0}\d+)): Used to capture one of two types:
-         * -?(\d+({0}\d*)?): Captures a decimal number starting with a number (e.g. "-1.23")
-         * -?({0}\d+): Captures a decimal number without leading number (e.g. ".23")
-         * e: Captures 'e' or 'E'
-         * (-?\d+): Captures an integer number (e.g. "-1" or "23")
-         */
-        var p = @"(-?(\d+(\.\d*)?)|-?(\.\d+))e(-?\d+)";
-        return Regex.Replace(input, p, "($1 * 10^($5))", RegexOptions.IgnoreCase);
+        return ReplaceScientificNotationRegex.Replace(input, "($1 * 10^($2))");
     }
 
     /*
@@ -292,6 +382,86 @@ public static class CalculateHelper
         return modifiedInput;
     }
 
+    public static string UpdateFactorialFunctions(string input)
+    {
+        // Handle n! -> factorial(n)
+        int startSearch = 0;
+        while (true)
+        {
+            var index = input.IndexOf('!', startSearch);
+            if (index == -1)
+            {
+                break;
+            }
+
+            // Ignore !=
+            if (index + 1 < input.Length && input[index + 1] == '=')
+            {
+                startSearch = index + 2;
+                continue;
+            }
+
+            if (index == 0)
+            {
+                startSearch = index + 1;
+                continue;
+            }
+
+            // Scan backwards
+            var endArg = index - 1;
+            while (endArg >= 0 && char.IsWhiteSpace(input[endArg]))
+            {
+                endArg--;
+            }
+
+            if (endArg < 0)
+            {
+                startSearch = index + 1;
+                continue;
+            }
+
+            var startArg = endArg;
+            if (input[endArg] == ')')
+            {
+                // Find matching '('
+                startArg = FindOpeningBracketIndexInFrontOfIndex(input, endArg);
+                if (startArg == -1)
+                {
+                    startSearch = index + 1;
+                    continue;
+                }
+            }
+            else
+            {
+                // Scan back for number or word
+                while (startArg >= 0 && (char.IsLetterOrDigit(input[startArg]) || input[startArg] == '.'))
+                {
+                    startArg--;
+                }
+
+                startArg++; // Move back to first valid char
+            }
+
+            if (startArg > endArg)
+            {
+                // No argument found
+                startSearch = index + 1;
+                continue;
+            }
+
+            // Extract argument
+            var arg = input.Substring(startArg, endArg - startArg + 1);
+
+            // Replace <arg><whitespace>! with factorial(<arg>)
+            input = input.Remove(startArg, index - startArg + 1);
+            input = input.Insert(startArg, $"factorial({arg})");
+
+            startSearch = 0; // Reset search because string changed
+        }
+
+        return input;
+    }
+
     private static string ModifyMathFunction(string input, string function, string modification)
     {
         // Create the pattern to match the function, opening bracket, and any spaces in between
@@ -325,4 +495,43 @@ public static class CalculateHelper
 
         return modifiedInput;
     }
+
+    private static int FindOpeningBracketIndexInFrontOfIndex(string input, int end)
+    {
+        var bracketCount = 0;
+        for (var i = end; i >= 0; i--)
+        {
+            switch (input[i])
+            {
+                case ')':
+                    bracketCount++;
+                    break;
+                case '(':
+                {
+                    bracketCount--;
+                    if (bracketCount == 0)
+                    {
+                        return i;
+                    }
+
+                    break;
+                }
+            }
+        }
+
+        return -1;
+    }
+
+    /*
+     * NOTE: By the time that the expression gets to us, it's already in English format.
+     *
+     * Regex explanation:
+     * (-?(\d+({0}\d*)?)|-?({0}\d+)): Used to capture one of two types:
+     * -?(\d+({0}\d*)?): Captures a decimal number starting with a number (e.g. "-1.23")
+     * -?({0}\d+): Captures a decimal number without leading number (e.g. ".23")
+     * e: Captures 'e' or 'E'
+     * (?\d+): Captures an integer number (e.g. "-1" or "23")
+     */
+    [GeneratedRegex(@"(\d+(?:\.\d*)?|\.\d+)e(-?\d+)", RegexOptions.IgnoreCase, "en-US")]
+    private static partial Regex CreateReplaceScientificNotationRegex();
 }

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Helper/ISettingsInterface.cs

@@ -2,8 +2,6 @@
 // The Microsoft Corporation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
-using Microsoft.CmdPal.Ext.Calc.Helper;
-
 namespace Microsoft.CmdPal.Ext.Calc.Helper;
 
 public interface ISettingsInterface
@@ -15,4 +13,8 @@ public interface ISettingsInterface
     public bool OutputUseEnglishFormat { get; }
 
     public bool CloseOnEnter { get; }
+
+    public bool CopyResultToSearchBarIfQueryEndsWithEqualSign { get; }
+
+    public bool AutoFixQuery { get; }
 }

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Helper/QueryHelper.cs

@@ -12,7 +12,13 @@ namespace Microsoft.CmdPal.Ext.Calc.Helper;
 
 public static partial class QueryHelper
 {
-    public static ListItem Query(string query, ISettingsInterface settings, bool isFallbackSearch, TypedEventHandler<object, object> handleSave = null)
+    public static ListItem Query(
+        string query,
+        ISettingsInterface settings,
+        bool isFallbackSearch,
+        out string displayQuery,
+        TypedEventHandler<object, object> handleSave = null,
+        TypedEventHandler<object, object> handleReplace = null)
     {
         ArgumentNullException.ThrowIfNull(query);
         if (!isFallbackSearch)
@@ -20,26 +26,50 @@ public static partial class QueryHelper
             ArgumentNullException.ThrowIfNull(handleSave);
         }
 
-        CultureInfo inputCulture = settings.InputUseEnglishFormat ? new CultureInfo("en-us") : CultureInfo.CurrentCulture;
-        CultureInfo outputCulture = settings.OutputUseEnglishFormat ? new CultureInfo("en-us") : CultureInfo.CurrentCulture;
+        CultureInfo inputCulture =
+            settings.InputUseEnglishFormat ? new CultureInfo("en-us") : CultureInfo.CurrentCulture;
+        CultureInfo outputCulture =
+            settings.OutputUseEnglishFormat ? new CultureInfo("en-us") : CultureInfo.CurrentCulture;
 
         // In case the user pastes a query with a leading =
-        query = query.TrimStart('=');
+        query = query.TrimStart('=').TrimStart();
+
+        // Enables better looking characters for multiplication and division (e.g., '×' and '÷')
+        displayQuery = CalculateHelper.NormalizeCharsForDisplayQuery(query);
 
         // Happens if the user has only typed the action key so far
-        if (string.IsNullOrEmpty(query))
+        if (string.IsNullOrEmpty(displayQuery))
         {
             return null;
         }
 
-        NumberTranslator translator = NumberTranslator.Create(inputCulture, new CultureInfo("en-US"));
-        var input = translator.Translate(query.Normalize(NormalizationForm.FormKC));
+        // Normalize query to engine format (e.g., replace '×' with '*', converts superscripts to functions)
+        // This must be done before any further normalization to avoid losing information
+        var engineQuery = CalculateHelper.NormalizeCharsToEngine(displayQuery);
+
+        // Cleanup rest of the Unicode characters, whitespace
+        var queryForEngine2 = engineQuery.Normalize(NormalizationForm.FormKC);
+
+        // Translate numbers from input culture to en-US culture for the calculation engine
+        var translator = NumberTranslator.Create(inputCulture, new CultureInfo("en-US"));
+
+        // Translate the input query
+        var input = translator.Translate(queryForEngine2);
 
         if (string.IsNullOrWhiteSpace(input))
         {
             return ErrorHandler.OnError(isFallbackSearch, query, Properties.Resources.calculator_expression_empty);
         }
 
+        // normalize again to engine chars after translation
+        input = CalculateHelper.NormalizeCharsToEngine(input);
+
+        // Auto fix incomplete queries (if enabled)
+        if (settings.AutoFixQuery && TryGetIncompleteQuery(input, out var newInput))
+        {
+            input = newInput;
+        }
+
         if (!CalculateHelper.InputValid(input))
         {
             return null;
@@ -60,10 +90,10 @@ public static partial class QueryHelper
             if (isFallbackSearch)
             {
                 // Fallback search
-                return ResultHelper.CreateResult(result.RoundedResult, inputCulture, outputCulture, query);
+                return ResultHelper.CreateResult(result.RoundedResult, inputCulture, outputCulture, displayQuery);
             }
 
-            return ResultHelper.CreateResult(result.RoundedResult, inputCulture, outputCulture, query, settings, handleSave);
+            return ResultHelper.CreateResult(result.RoundedResult, inputCulture, outputCulture, displayQuery, settings, handleSave, handleReplace);
         }
         catch (OverflowException)
         {
@@ -77,4 +107,32 @@ public static partial class QueryHelper
             return ErrorHandler.OnError(isFallbackSearch, query, default, e);
         }
     }
+
+    public static bool TryGetIncompleteQuery(string query, out string newQuery)
+    {
+        newQuery = query;
+
+        var trimmed = query.TrimEnd();
+        if (string.IsNullOrEmpty(trimmed))
+        {
+            return false;
+        }
+
+        // 1. Trim trailing operators
+        var operators = CalculateHelper.GetQueryOperators();
+        while (trimmed.Length > 0 && Array.IndexOf(operators, trimmed[^1]) > -1)
+        {
+            trimmed = trimmed[..^1].TrimEnd();
+        }
+
+        if (trimmed.Length == 0)
+        {
+            return false;
+        }
+
+        // 2. Fix brackets
+        newQuery = BracketHelper.BalanceBrackets(trimmed);
+
+        return true;
+    }
 }

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Helper/ReplaceQueryCommand.cs

@@ -0,0 +1,26 @@
+// 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 Microsoft.CommandPalette.Extensions;
+using Microsoft.CommandPalette.Extensions.Toolkit;
+using Windows.Foundation;
+
+namespace Microsoft.CmdPal.Ext.Calc.Helper;
+
+public sealed partial class ReplaceQueryCommand : InvokableCommand
+{
+    public event TypedEventHandler<object, object> ReplaceRequested;
+
+    public ReplaceQueryCommand()
+    {
+        Name = "Replace query";
+        Icon = new IconInfo("\uE70F"); // Edit icon
+    }
+
+    public override ICommandResult Invoke()
+    {
+        ReplaceRequested?.Invoke(this, null);
+        return CommandResult.KeepOpen();
+    }
+}

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Helper/ResultHelper.cs

@@ -6,6 +6,7 @@ using System;
 using System.Collections.Generic;
 using System.Globalization;
 using ManagedCommon;
+using Microsoft.CommandPalette.Extensions;
 using Microsoft.CommandPalette.Extensions.Toolkit;
 using Windows.Foundation;
 
@@ -13,7 +14,14 @@ namespace Microsoft.CmdPal.Ext.Calc.Helper;
 
 public static class ResultHelper
 {
-    public static ListItem CreateResult(decimal? roundedResult, CultureInfo inputCulture, CultureInfo outputCulture, string query, ISettingsInterface settings, TypedEventHandler<object, object> handleSave)
+    public static ListItem CreateResult(
+        decimal? roundedResult,
+        CultureInfo inputCulture,
+        CultureInfo outputCulture,
+        string query,
+        ISettingsInterface settings,
+        TypedEventHandler<object, object> handleSave,
+        TypedEventHandler<object, object> handleReplace)
     {
         // Return null when the expression is not a valid calculator query.
         if (roundedResult is null)
@@ -28,6 +36,9 @@ public static class ResultHelper
         var saveCommand = new SaveCommand(result);
         saveCommand.SaveRequested += handleSave;
 
+        var replaceCommand = new ReplaceQueryCommand();
+        replaceCommand.ReplaceRequested += handleReplace;
+
         var copyCommandItem = CreateResult(roundedResult, inputCulture, outputCulture, query);
 
         // No TextToSuggest on the main save command item. We don't want to keep suggesting what the result is,
@@ -40,6 +51,7 @@ public static class ResultHelper
             Subtitle = query,
             MoreCommands = [
                 new CommandContextItem(settings.CloseOnEnter ? saveCommand : copyCommandItem.Command),
+                new CommandContextItem(replaceCommand) { RequestedShortcut = KeyChords.CopyResultToSearchBox, },
                 ..copyCommandItem.MoreCommands,
             ],
         };
@@ -55,11 +67,15 @@ public static class ResultHelper
 
         var decimalResult = roundedResult?.ToString(outputCulture);
 
-        List<CommandContextItem> context = [];
+        List<IContextItem> context = [];
 
         if (decimal.IsInteger((decimal)roundedResult))
         {
+            context.Add(new Separator());
+
             var i = decimal.ToInt64((decimal)roundedResult);
+
+            // hexadecimal
             try
             {
                 var hexResult = "0x" + i.ToString("X", outputCulture);
@@ -70,9 +86,10 @@ public static class ResultHelper
             }
             catch (Exception ex)
             {
-                Logger.LogError("Error parsing hex format", ex);
+                Logger.LogError("Error converting to hex format", ex);
             }
 
+            // binary
             try
             {
                 var binaryResult = "0b" + i.ToString("B", outputCulture);
@@ -83,7 +100,21 @@ public static class ResultHelper
             }
             catch (Exception ex)
             {
-                Logger.LogError("Error parsing binary format", ex);
+                Logger.LogError("Error converting to binary format", ex);
+            }
+
+            // octal
+            try
+            {
+                var octalResult = "0o" + Convert.ToString(i, 8);
+                context.Add(new CommandContextItem(new CopyTextCommand(octalResult) { Name = Properties.Resources.calculator_copy_octal })
+                {
+                    Title = octalResult,
+                });
+            }
+            catch (Exception ex)
+            {
+                Logger.LogError("Error converting to octal format", ex);
             }
         }
 

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Helper/SettingsManager.cs

@@ -45,6 +45,18 @@ public class SettingsManager : JsonSettingsManager, ISettingsInterface
         Properties.Resources.calculator_settings_close_on_enter_description,
         true);
 
+    private readonly ToggleSetting _copyResultToSearchBarIfQueryEndsWithEqualSign = new(
+        Namespaced(nameof(CopyResultToSearchBarIfQueryEndsWithEqualSign)),
+        Properties.Resources.calculator_settings_copy_result_to_search_bar,
+        Properties.Resources.calculator_settings_copy_result_to_search_bar_description,
+        false);
+
+    private readonly ToggleSetting _autoFixQuery = new(
+        Namespaced(nameof(AutoFixQuery)),
+        Properties.Resources.calculator_settings_auto_fix_query,
+        Properties.Resources.calculator_settings_auto_fix_query_description,
+        true);
+
     public CalculateEngine.TrigMode TrigUnit
     {
         get
@@ -81,6 +93,10 @@ public class SettingsManager : JsonSettingsManager, ISettingsInterface
 
     public bool CloseOnEnter => _closeOnEnter.Value;
 
+    public bool CopyResultToSearchBarIfQueryEndsWithEqualSign => _copyResultToSearchBarIfQueryEndsWithEqualSign.Value;
+
+    public bool AutoFixQuery => _autoFixQuery.Value;
+
     internal static string SettingsJsonPath()
     {
         var directory = Utilities.BaseSettingsPath("Microsoft.CmdPal");
@@ -98,6 +114,8 @@ public class SettingsManager : JsonSettingsManager, ISettingsInterface
         Settings.Add(_inputUseEnNumberFormat);
         Settings.Add(_outputUseEnNumberFormat);
         Settings.Add(_closeOnEnter);
+        Settings.Add(_copyResultToSearchBarIfQueryEndsWithEqualSign);
+        Settings.Add(_autoFixQuery);
 
         // Load settings from file upon initialization
         LoadSettings();

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/KeyChords.cs

@@ -0,0 +1,13 @@
+// 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 Microsoft.CommandPalette.Extensions;
+using Windows.System;
+
+namespace Microsoft.CmdPal.Ext.Calc;
+
+internal static class KeyChords
+{
+    internal static KeyChord CopyResultToSearchBox { get; } = new(VirtualKeyModifiers.Control | VirtualKeyModifiers.Shift, (int)VirtualKey.Enter, 0);
+}

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Pages/CalculatorListPage.cs

@@ -25,12 +25,12 @@ public sealed partial class CalculatorListPage : DynamicListPage
     private readonly Lock _resultsLock = new();
     private readonly ISettingsInterface _settingsManager;
     private readonly List<ListItem> _items = [];
-    private readonly List<ListItem> history = [];
+    private readonly List<ListItem> _history = [];
     private readonly ListItem _emptyItem;
 
     // This is the text that saved when the user click the result.
     // We need to avoid the double calculation. This may cause some wierd behaviors.
-    private string skipQuerySearchText = string.Empty;
+    private string _skipQuerySearchText = string.Empty;
 
     public CalculatorListPage(ISettingsInterface settings)
     {
@@ -54,6 +54,17 @@ public sealed partial class CalculatorListPage : DynamicListPage
         UpdateSearchText(string.Empty, string.Empty);
     }
 
+    private void HandleReplaceQuery(object sender, object args)
+    {
+        var lastResult = _items[0].Title;
+        if (!string.IsNullOrEmpty(lastResult))
+        {
+            _skipQuerySearchText = lastResult;
+            SearchText = lastResult;
+            OnPropertyChanged(nameof(SearchText));
+        }
+    }
+
     public override void UpdateSearchText(string oldSearch, string newSearch)
     {
         if (oldSearch == newSearch)
@@ -61,19 +72,37 @@ public sealed partial class CalculatorListPage : DynamicListPage
             return;
         }
 
-        if (!string.IsNullOrEmpty(skipQuerySearchText) && newSearch == skipQuerySearchText)
+        if (!string.IsNullOrEmpty(_skipQuerySearchText) && newSearch == _skipQuerySearchText)
         {
             // only skip once.
-            skipQuerySearchText = string.Empty;
+            _skipQuerySearchText = string.Empty;
             return;
         }
 
-        skipQuerySearchText = string.Empty;
+        var copyResultToSearchText = false;
+        if (_settingsManager.CopyResultToSearchBarIfQueryEndsWithEqualSign && newSearch.EndsWith('='))
+        {
+            newSearch = newSearch.TrimEnd('=').TrimEnd();
+            copyResultToSearchText = true;
+        }
+
+        _skipQuerySearchText = string.Empty;
 
         _emptyItem.Subtitle = newSearch;
 
-        var result = QueryHelper.Query(newSearch, _settingsManager, false, HandleSave);
+        var result = QueryHelper.Query(newSearch, _settingsManager, isFallbackSearch: false, out var displayQuery, HandleSave, HandleReplaceQuery);
+
         UpdateResult(result);
+
+        if (copyResultToSearchText && result is not null)
+        {
+            _skipQuerySearchText = result.Title;
+            SearchText = result.Title;
+
+            // LOAD BEARING: The SearchText setter does not raise a PropertyChanged notification,
+            // so we must raise it explicitly to ensure the UI updates correctly.
+            OnPropertyChanged(nameof(SearchText));
+        }
     }
 
     private void UpdateResult(ListItem result)
@@ -91,7 +120,7 @@ public sealed partial class CalculatorListPage : DynamicListPage
                 _items.Add(_emptyItem);
             }
 
-            this._items.AddRange(history);
+            this._items.AddRange(_history);
         }
 
         RaiseItemsChanged(this._items.Count);
@@ -109,7 +138,7 @@ public sealed partial class CalculatorListPage : DynamicListPage
                 TextToSuggest = lastResult,
             };
 
-            history.Insert(0, li);
+            _history.Insert(0, li);
             _items.Insert(1, li);
 
             // Why we need to clean the query record? Removed, but if necessary, please move it back.
@@ -117,9 +146,14 @@ public sealed partial class CalculatorListPage : DynamicListPage
 
             // this change will call the UpdateSearchText again.
             // We need to avoid it.
-            skipQuerySearchText = lastResult;
+            _skipQuerySearchText = lastResult;
             SearchText = lastResult;
-            this.RaiseItemsChanged(this._items.Count);
+
+            // LOAD BEARING: The SearchText setter does not raise a PropertyChanged notification,
+            // so we must raise it explicitly to ensure the UI updates correctly.
+            OnPropertyChanged(nameof(SearchText));
+
+            RaiseItemsChanged(this._items.Count);
         }
     }
 

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Pages/FallbackCalculatorItem.cs

@@ -27,7 +27,7 @@ public sealed partial class FallbackCalculatorItem : FallbackCommandItem
 
     public override void UpdateQuery(string query)
     {
-        var result = QueryHelper.Query(query, _settings, true, null);
+        var result = QueryHelper.Query(query, _settings, true, out _);
 
         if (result is null)
         {

src/modules/cmdpal/ext/Microsoft.CmdPal.Ext.Calc/Properties/Resources.Designer.cs

@@ -19,7 +19,7 @@ namespace Microsoft.CmdPal.Ext.Calc.Properties {
     // class via a tool like ResGen or Visual Studio.
     // To add or remove a member, edit your .ResX file then rerun ResGen
     // with the /str option, or rebuild your VS project.
-    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "17.0.0.0")]
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "18.0.0.0")]
     [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
     [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
     public class Resources {
@@ -96,6 +96,15 @@ namespace Microsoft.CmdPal.Ext.Calc.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Copy octal.
+        /// </summary>
+        public static string calculator_copy_octal {
+            get {
+                return ResourceManager.GetString("calculator_copy_octal", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Calculator.
         /// </summary>
@@ -186,6 +195,24 @@ namespace Microsoft.CmdPal.Ext.Calc.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Fix incomplete calculations automatically.
+        /// </summary>
+        public static string calculator_settings_auto_fix_query {
+            get {
+                return ResourceManager.GetString("calculator_settings_auto_fix_query", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Attempt to evaluate incomplete calculations by ignoring extra operators or symbols.
+        /// </summary>
+        public static string calculator_settings_auto_fix_query_description {
+            get {
+                return ResourceManager.GetString("calculator_settings_auto_fix_query_description", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Close on Enter.
         /// </summary>
@@ -204,6 +231,24 @@ namespace Microsoft.CmdPal.Ext.Calc.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Replace query with result on equals.
+        /// </summary>
+        public static string calculator_settings_copy_result_to_search_bar {
+            get {
+                return ResourceManager.GetString("calculator_settings_copy_result_to_search_bar", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Updates the query to the result when (=) is entered.
+        /// </summary>
+        public static string calculator_settings_copy_result_to_search_bar_description {
+            get {
+                return ResourceManager.GetString("calculator_settings_copy_result_to_search_bar_description", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Use English (United States) number format for input.
         /// </summary>
@@ -222,6 +267,24 @@ namespace Microsoft.CmdPal.Ext.Calc.Properties {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Handle extra operators and symbols.
+        /// </summary>
+        public static string calculator_settings_input_normalization {
+            get {
+                return ResourceManager.GetString("calculator_settings_input_normalization", resourceCulture);
+            }
+        }
+        
+        /// <summary>
+        ///   Looks up a localized string similar to Enable advanced input normalization and extra symbols (e.g. ÷, ×, π).
+        /// </summary>
+        public static string calculator_settings_input_normalization_description {
+            get {
+                return ResourceManager.GetString("calculator_settings_input_normalization_description", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Use English (United States) number format for output.
         /// </summary>