From 41f339d4fe8fd2fef03de38a02d223dc07f421d6 Mon Sep 17 00:00:00 2001
From: Stuart Meeks <stuart.meeks@stuartmeeks.net>
Date: Sat, 30 May 2026 12:34:44 +0000
Subject: [PATCH] Shared parameter definitions: management UI (2/2)

Adds the authoring surfaces for the shared-parameter resolution landed in
part 1:
- CLI-scoped params: a "Shared parameters" section in the CLI editor dialog
  (reuses the existing parameter-row editor); CliEditorViewModel gains an
  editable Parameters collection.
- Global params: a new GlobalParametersViewModel content view, opened from a
  "Shared parameters" entry in the pane footer (Trash-style), with add/remove
  rows and a Save persisted by ShellViewModel.SaveGlobalParameters. Global
  params live in the main UI, not Settings, per the agreed design.

Both reuse ParameterEditorRowViewModel and the existing param-row layout.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
---
 CHANGELOG.md                                  |  17 ++-
 src/Snipdeck.App/Views/CliEditorDialog.xaml   | 101 +++++++++++++++---
 .../Views/CliEditorDialog.xaml.cs             |  13 +++
 .../Views/ShellContentTemplateSelector.cs     |   3 +
 src/Snipdeck.App/Views/ShellPage.xaml         | 100 ++++++++++++++++-
 src/Snipdeck.App/Views/ShellPage.xaml.cs      |   5 +
 .../ViewModels/CliEditorViewModel.cs          |  21 +++-
 .../ViewModels/GlobalParametersViewModel.cs   |  48 +++++++++
 .../ViewModels/ShellViewModel.cs              |  19 ++++
 .../ViewModels/CliEditorViewModelTests.cs     |  21 +++-
 .../GlobalParametersViewModelTests.cs         |  42 ++++++++
 .../ViewModels/ShellViewModelCommandsTests.cs |  19 ++++
 12 files changed, 376 insertions(+), 33 deletions(-)
 create mode 100644 src/Snipdeck.Core/ViewModels/GlobalParametersViewModel.cs
 create mode 100644 tests/Snipdeck.Core.Tests/ViewModels/GlobalParametersViewModelTests.cs

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 10f04fa..a3d0e06 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,15 +8,6 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Changed
-- **Shared parameter definitions — resolution groundwork.** A Snip's
-  `{token}` now resolves its parameter definition by name with precedence:
-  the Snip's own parameter overrides a CLI-scoped one, which overrides a
-  global one. A Snip can omit a parameter to inherit the shared definition
-  (e.g. an `env` Choice defined once on a CLI). Store schema is now v2
-  (additive: `Cli.Parameters` + `SnipStoreDocument.GlobalParameters`); an
-  older build refuses a v2 store rather than dropping shared definitions.
-  The UI to manage shared parameters lands next; existing snips are
-  unaffected.
 - **JSON stores moved to System.Text.Json source generation.** `JsonSnipStore`
   and `JsonSettingsStore` now serialise via a generated `JsonSerializerContext`
   instead of the reflection-based serializer, removing the IL2026 trim warnings.
@@ -26,6 +17,14 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   IL2104 on the WinAppSDK/WinRT/Jdenticon assemblies, which aren't trim-safe.
 
 ### Added
+- **Shared parameter definitions.** Define a parameter once and reuse it
+  across snips, at two scopes: **CLI-scoped** (in the CLI editor — inherited by
+  every snip under that CLI) and **global** (a new "Shared parameters" entry in
+  the left pane — available to every snip across all CLIs). A snip's `{token}`
+  resolves its definition by name with precedence **snip-local → CLI → global**;
+  omit a parameter to inherit the shared one, or define it locally to override.
+  Existing snips are unaffected. (Store schema is now v2; an older build refuses
+  a v2 store rather than dropping shared definitions.)
 - **Change the storage location.** A "Change…" button on Settings → Storage
   location lets you pick a new folder for your snips. If the folder already
   contains a Snipdeck store it's adopted (your current snips are left where
diff --git a/src/Snipdeck.App/Views/CliEditorDialog.xaml b/src/Snipdeck.App/Views/CliEditorDialog.xaml
index 184222e..051280b 100644
--- a/src/Snipdeck.App/Views/CliEditorDialog.xaml
+++ b/src/Snipdeck.App/Views/CliEditorDialog.xaml
@@ -3,6 +3,7 @@
     x:Class="Snipdeck.App.Views.CliEditorDialog"
     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:vm="using:Snipdeck.Core.ViewModels"
     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
     mc:Ignorable="d"
@@ -11,30 +12,96 @@
     CloseButtonText="Cancel"
     DefaultButton="Primary">
 
-    <StackPanel MinWidth="400" Spacing="12">
-        <TextBox Header="Name"
-                 Text="{x:Bind ViewModel.Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+    <ScrollViewer VerticalScrollBarVisibility="Auto" MaxHeight="560">
+        <StackPanel MinWidth="400" Spacing="12">
+            <TextBox Header="Name"
+                     Text="{x:Bind ViewModel.Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+
+            <StackPanel Spacing="6">
+                <TextBlock Text="Icon"
+                           Style="{ThemeResource BodyStrongTextBlockStyle}" />
+                <TextBlock Text="Defaults to a deterministic identicon. Upload an image to override; it'll be cropped square and resized to 256×256."
+                           Style="{ThemeResource CaptionTextBlockStyle}"
+                           Foreground="{ThemeResource TextFillColorSecondaryBrush}"
+                           TextWrapping="Wrap" />
+                <Grid>
+                    <Grid.ColumnDefinitions>
+                        <ColumnDefinition Width="*" />
+                        <ColumnDefinition Width="Auto" />
+                    </Grid.ColumnDefinitions>
+                    <TextBlock Grid.Column="0"
+                               Text="{x:Bind ViewModel.PickedIconFileName, Mode=OneWay}"
+                               VerticalAlignment="Center"
+                               TextTrimming="CharacterEllipsis" />
+                    <Button Grid.Column="1"
+                            Content="Choose image..."
+                            Click="OnPickIconClicked" />
+                </Grid>
+            </StackPanel>
 
-        <StackPanel Spacing="6">
-            <TextBlock Text="Icon"
-                       Style="{ThemeResource BodyStrongTextBlockStyle}" />
-            <TextBlock Text="Defaults to a deterministic identicon. Upload an image to override; it'll be cropped square and resized to 256×256."
-                       Style="{ThemeResource CaptionTextBlockStyle}"
-                       Foreground="{ThemeResource TextFillColorSecondaryBrush}"
-                       TextWrapping="Wrap" />
             <Grid>
                 <Grid.ColumnDefinitions>
                     <ColumnDefinition Width="*" />
                     <ColumnDefinition Width="Auto" />
                 </Grid.ColumnDefinitions>
-                <TextBlock Grid.Column="0"
-                           Text="{x:Bind ViewModel.PickedIconFileName, Mode=OneWay}"
-                           VerticalAlignment="Center"
-                           TextTrimming="CharacterEllipsis" />
+                <StackPanel Grid.Column="0" VerticalAlignment="Center">
+                    <TextBlock Text="Shared parameters"
+                               Style="{ThemeResource BodyStrongTextBlockStyle}" />
+                    <TextBlock Text="Inherited by every snip under this CLI that uses the matching {token}."
+                               Style="{ThemeResource CaptionTextBlockStyle}"
+                               Foreground="{ThemeResource TextFillColorSecondaryBrush}"
+                               TextWrapping="Wrap" />
+                </StackPanel>
                 <Button Grid.Column="1"
-                        Content="Choose image..."
-                        Click="OnPickIconClicked" />
+                        VerticalAlignment="Top"
+                        Content="Add parameter"
+                        Click="OnAddParameterClicked" />
             </Grid>
+
+            <ItemsControl ItemsSource="{x:Bind ViewModel.Parameters}">
+                <ItemsControl.ItemsPanel>
+                    <ItemsPanelTemplate>
+                        <StackPanel Spacing="8" />
+                    </ItemsPanelTemplate>
+                </ItemsControl.ItemsPanel>
+                <ItemsControl.ItemTemplate>
+                    <DataTemplate x:DataType="vm:ParameterEditorRowViewModel">
+                        <Border Background="{ThemeResource SubtleFillColorSecondaryBrush}"
+                                CornerRadius="6"
+                                Padding="12">
+                            <StackPanel Spacing="8">
+                                <Grid>
+                                    <Grid.ColumnDefinitions>
+                                        <ColumnDefinition Width="*" />
+                                        <ColumnDefinition Width="Auto" />
+                                    </Grid.ColumnDefinitions>
+                                    <TextBox Grid.Column="0"
+                                             Header="Name"
+                                             Text="{x:Bind Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+                                    <Button Grid.Column="1"
+                                            Margin="8,24,0,0"
+                                            Click="OnRemoveParameterClicked"
+                                            Tag="{x:Bind}"
+                                            ToolTipService.ToolTip="Remove parameter">
+                                        <FontIcon Glyph="&#xE74D;" FontSize="14" />
+                                    </Button>
+                                </Grid>
+                                <ComboBox Header="Type"
+                                          SelectedIndex="{x:Bind TypeIndex, Mode=TwoWay}"
+                                          HorizontalAlignment="Stretch">
+                                    <x:String>Text</x:String>
+                                    <x:String>Choice</x:String>
+                                </ComboBox>
+                                <TextBox Header="Default"
+                                         Text="{x:Bind Default, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+                                <TextBox Header="Options (comma-separated, Choice only)"
+                                         Text="{x:Bind OptionsText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
+                                         IsEnabled="{x:Bind IsChoice, Mode=OneWay}" />
+                            </StackPanel>
+                        </Border>
+                    </DataTemplate>
+                </ItemsControl.ItemTemplate>
+            </ItemsControl>
         </StackPanel>
-    </StackPanel>
+    </ScrollViewer>
 </ContentDialog>
diff --git a/src/Snipdeck.App/Views/CliEditorDialog.xaml.cs b/src/Snipdeck.App/Views/CliEditorDialog.xaml.cs
index e3da04d..278d57f 100644
--- a/src/Snipdeck.App/Views/CliEditorDialog.xaml.cs
+++ b/src/Snipdeck.App/Views/CliEditorDialog.xaml.cs
@@ -34,6 +34,19 @@ private void UpdatePrimaryButtonEnabled()
             IsPrimaryButtonEnabled = ViewModel.CanSave;
         }
 
+        private void OnAddParameterClicked(object sender, RoutedEventArgs e)
+        {
+            ViewModel.AddParameter();
+        }
+
+        private void OnRemoveParameterClicked(object sender, RoutedEventArgs e)
+        {
+            if (sender is FrameworkElement element && element.Tag is ParameterEditorRowViewModel row)
+            {
+                ViewModel.RemoveParameter(row);
+            }
+        }
+
         private async void OnPickIconClicked(object sender, RoutedEventArgs e)
         {
             var picked = await _filePicker.PickImageAsync();
diff --git a/src/Snipdeck.App/Views/ShellContentTemplateSelector.cs b/src/Snipdeck.App/Views/ShellContentTemplateSelector.cs
index 5c37434..ec2a33c 100644
--- a/src/Snipdeck.App/Views/ShellContentTemplateSelector.cs
+++ b/src/Snipdeck.App/Views/ShellContentTemplateSelector.cs
@@ -19,6 +19,8 @@ public sealed partial class ShellContentTemplateSelector : DataTemplateSelector
 
         public DataTemplate? TrashTemplate { get; set; }
 
+        public DataTemplate? GlobalParametersTemplate { get; set; }
+
         protected override DataTemplate? SelectTemplateCore(object item)
         {
             return item switch
@@ -27,6 +29,7 @@ public sealed partial class ShellContentTemplateSelector : DataTemplateSelector
                 CliViewModel => CliTemplate,
                 SettingsViewModel => SettingsTemplate,
                 TrashViewModel => TrashTemplate,
+                GlobalParametersViewModel => GlobalParametersTemplate,
                 _ => null,
             };
         }
diff --git a/src/Snipdeck.App/Views/ShellPage.xaml b/src/Snipdeck.App/Views/ShellPage.xaml
index e4f81df..9400993 100644
--- a/src/Snipdeck.App/Views/ShellPage.xaml
+++ b/src/Snipdeck.App/Views/ShellPage.xaml
@@ -17,6 +17,7 @@
         <converters:BoolToVisibilityConverter x:Key="BoolToVisibility" />
         <converters:BoolToVisibilityConverter x:Key="InvertedBoolToVisibility" Invert="True" />
         <converters:CountToVisibilityConverter x:Key="CountToVisibility" />
+        <converters:CountToVisibilityConverter x:Key="InvertedCountToVisibility" Invert="True" />
         <converters:EmptyStringToVisibilityConverter x:Key="EmptyStringToVisibility" />
 
         <DataTemplate x:Key="HomeContentTemplate" x:DataType="vm:HomeViewModel">
@@ -316,11 +317,97 @@
             </ScrollViewer>
         </DataTemplate>
 
+        <DataTemplate x:Key="GlobalParametersContentTemplate" x:DataType="vm:GlobalParametersViewModel">
+            <ScrollViewer VerticalScrollBarVisibility="Auto">
+                <StackPanel Padding="24" Spacing="16" MaxWidth="720" HorizontalAlignment="Stretch">
+                    <Grid>
+                        <Grid.ColumnDefinitions>
+                            <ColumnDefinition Width="*" />
+                            <ColumnDefinition Width="Auto" />
+                            <ColumnDefinition Width="Auto" />
+                        </Grid.ColumnDefinitions>
+                        <StackPanel Grid.Column="0" VerticalAlignment="Center">
+                            <TextBlock Text="Shared parameters"
+                                       Style="{ThemeResource TitleTextBlockStyle}" />
+                            <TextBlock Text="Definitions available to every snip across all CLIs. A snip inherits one when its {token} matches and neither the snip nor its CLI defines that name."
+                                       Style="{ThemeResource CaptionTextBlockStyle}"
+                                       Foreground="{ThemeResource TextFillColorSecondaryBrush}"
+                                       TextWrapping="Wrap" />
+                        </StackPanel>
+                        <Button Grid.Column="1"
+                                Margin="0,0,8,0"
+                                Content="Add parameter"
+                                Command="{x:Bind AddParameterCommand}" />
+                        <Button Grid.Column="2"
+                                Content="Save"
+                                Style="{ThemeResource AccentButtonStyle}"
+                                Command="{Binding ElementName=ShellRoot, Path=ViewModel.SaveGlobalParametersCommand}" />
+                    </Grid>
+
+                    <TextBlock Text="{x:Bind StatusMessage, Mode=OneWay}"
+                               Style="{ThemeResource CaptionTextBlockStyle}"
+                               Foreground="{ThemeResource TextFillColorSecondaryBrush}"
+                               Visibility="{x:Bind StatusMessage, Mode=OneWay, Converter={StaticResource EmptyStringToVisibility}}" />
+
+                    <TextBlock Text="No global parameters yet. Add one to share it across every CLI."
+                               Style="{ThemeResource BodyTextBlockStyle}"
+                               Foreground="{ThemeResource TextFillColorSecondaryBrush}"
+                               Visibility="{x:Bind Parameters.Count, Mode=OneWay, Converter={StaticResource InvertedCountToVisibility}}" />
+
+                    <ItemsControl ItemsSource="{x:Bind Parameters}">
+                        <ItemsControl.ItemsPanel>
+                            <ItemsPanelTemplate>
+                                <StackPanel Spacing="8" />
+                            </ItemsPanelTemplate>
+                        </ItemsControl.ItemsPanel>
+                        <ItemsControl.ItemTemplate>
+                            <DataTemplate x:DataType="vm:ParameterEditorRowViewModel">
+                                <Border Background="{ThemeResource SubtleFillColorSecondaryBrush}"
+                                        CornerRadius="6"
+                                        Padding="12">
+                                    <StackPanel Spacing="8">
+                                        <Grid>
+                                            <Grid.ColumnDefinitions>
+                                                <ColumnDefinition Width="*" />
+                                                <ColumnDefinition Width="Auto" />
+                                            </Grid.ColumnDefinitions>
+                                            <TextBox Grid.Column="0"
+                                                     Header="Name"
+                                                     Text="{x:Bind Name, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+                                            <Button Grid.Column="1"
+                                                    Margin="8,24,0,0"
+                                                    Command="{Binding ElementName=ShellRoot, Path=ViewModel.CurrentContent.RemoveParameterCommand}"
+                                                    CommandParameter="{x:Bind}"
+                                                    ToolTipService.ToolTip="Remove parameter">
+                                                <FontIcon Glyph="&#xE74D;" FontSize="14" />
+                                            </Button>
+                                        </Grid>
+                                        <ComboBox Header="Type"
+                                                  SelectedIndex="{x:Bind TypeIndex, Mode=TwoWay}"
+                                                  HorizontalAlignment="Stretch">
+                                            <x:String>Text</x:String>
+                                            <x:String>Choice</x:String>
+                                        </ComboBox>
+                                        <TextBox Header="Default"
+                                                 Text="{x:Bind Default, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+                                        <TextBox Header="Options (comma-separated, Choice only)"
+                                                 Text="{x:Bind OptionsText, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
+                                                 IsEnabled="{x:Bind IsChoice, Mode=OneWay}" />
+                                    </StackPanel>
+                                </Border>
+                            </DataTemplate>
+                        </ItemsControl.ItemTemplate>
+                    </ItemsControl>
+                </StackPanel>
+            </ScrollViewer>
+        </DataTemplate>
+
         <local:ShellContentTemplateSelector x:Key="ShellContentSelector"
                                              HomeTemplate="{StaticResource HomeContentTemplate}"
                                              CliTemplate="{StaticResource CliContentTemplate}"
                                              SettingsTemplate="{StaticResource SettingsContentTemplate}"
-                                             TrashTemplate="{StaticResource TrashContentTemplate}" />
+                                             TrashTemplate="{StaticResource TrashContentTemplate}"
+                                             GlobalParametersTemplate="{StaticResource GlobalParametersContentTemplate}" />
     </UserControl.Resources>
 
     <NavigationView x:Name="ShellNavigation"
@@ -347,6 +434,17 @@
 
         <NavigationView.PaneFooter>
             <StackPanel>
+                <Button x:Name="SharedParametersButton"
+                        Click="OnSharedParametersClicked"
+                        HorizontalAlignment="Stretch"
+                        Margin="12,8,12,0"
+                        Background="Transparent"
+                        BorderThickness="0">
+                    <StackPanel Orientation="Horizontal" Spacing="12">
+                        <FontIcon Glyph="&#xE8EC;" FontSize="16" />
+                        <TextBlock Text="Shared parameters" VerticalAlignment="Center" />
+                    </StackPanel>
+                </Button>
                 <Button x:Name="TrashButton"
                         Click="OnTrashClicked"
                         HorizontalAlignment="Stretch"
diff --git a/src/Snipdeck.App/Views/ShellPage.xaml.cs b/src/Snipdeck.App/Views/ShellPage.xaml.cs
index 09922fe..4f4d702 100644
--- a/src/Snipdeck.App/Views/ShellPage.xaml.cs
+++ b/src/Snipdeck.App/Views/ShellPage.xaml.cs
@@ -34,6 +34,11 @@ private void OnTrashClicked(object sender, RoutedEventArgs e)
             ViewModel.OpenTrash();
         }
 
+        private void OnSharedParametersClicked(object sender, RoutedEventArgs e)
+        {
+            ViewModel.OpenGlobalParameters();
+        }
+
         private void OnNavigationSelectionChanged(
             NavigationView sender,
             NavigationViewSelectionChangedEventArgs args)
diff --git a/src/Snipdeck.Core/ViewModels/CliEditorViewModel.cs b/src/Snipdeck.Core/ViewModels/CliEditorViewModel.cs
index 46ecd4b..8689b6b 100644
--- a/src/Snipdeck.Core/ViewModels/CliEditorViewModel.cs
+++ b/src/Snipdeck.Core/ViewModels/CliEditorViewModel.cs
@@ -1,3 +1,5 @@
+using System.Collections.ObjectModel;
+
 using CommunityToolkit.Mvvm.ComponentModel;
 
 using Snipdeck.Core.Models;
@@ -12,6 +14,8 @@ public CliEditorViewModel(Cli cli)
 
             Cli = cli;
             Name = cli.Name;
+            Parameters = new ObservableCollection<ParameterEditorRowViewModel>(
+                cli.Parameters.Select(p => new ParameterEditorRowViewModel(p)));
         }
 
         public Cli Cli { get; }
@@ -25,8 +29,21 @@ public CliEditorViewModel(Cli cli)
         [ObservableProperty]
         public partial string? PickedIconFileName { get; set; }
 
+        /// <summary>CLI-scoped shared parameter definitions (inherited by this CLI's snips).</summary>
+        public ObservableCollection<ParameterEditorRowViewModel> Parameters { get; }
+
         public bool CanSave => !string.IsNullOrWhiteSpace(Name);
 
+        public void AddParameter()
+        {
+            Parameters.Add(new ParameterEditorRowViewModel(new Parameter { Name = "param" }));
+        }
+
+        public void RemoveParameter(ParameterEditorRowViewModel row)
+        {
+            _ = Parameters.Remove(row);
+        }
+
         public Cli BuildUpdatedCli()
         {
             return new Cli
@@ -34,9 +51,7 @@ public Cli BuildUpdatedCli()
                 Id = Cli.Id,
                 Name = Name.Trim(),
                 IconRef = Cli.IconRef,
-                // Carry shared parameter definitions through the rebuild so a
-                // rename/icon edit doesn't wipe CLI-scoped parameters.
-                Parameters = Cli.Parameters,
+                Parameters = [.. Parameters.Select(r => r.BuildParameter())],
             };
         }
     }
diff --git a/src/Snipdeck.Core/ViewModels/GlobalParametersViewModel.cs b/src/Snipdeck.Core/ViewModels/GlobalParametersViewModel.cs
new file mode 100644
index 0000000..5d1e979
--- /dev/null
+++ b/src/Snipdeck.Core/ViewModels/GlobalParametersViewModel.cs
@@ -0,0 +1,48 @@
+using System.Collections.ObjectModel;
+
+using CommunityToolkit.Mvvm.ComponentModel;
+using CommunityToolkit.Mvvm.Input;
+
+using Snipdeck.Core.Models;
+
+namespace Snipdeck.Core.ViewModels
+{
+    /// <summary>
+    /// The "Shared parameters" content view: edits the global (cross-CLI)
+    /// parameter definitions. Add/remove rows here; the shell persists them via
+    /// its SaveGlobalParameters command.
+    /// </summary>
+    public sealed partial class GlobalParametersViewModel : ObservableObject
+    {
+        public GlobalParametersViewModel(IReadOnlyList<Parameter> parameters)
+        {
+            ArgumentNullException.ThrowIfNull(parameters);
+            Parameters = new ObservableCollection<ParameterEditorRowViewModel>(
+                parameters.Select(p => new ParameterEditorRowViewModel(p)));
+        }
+
+        public ObservableCollection<ParameterEditorRowViewModel> Parameters { get; }
+
+        [ObservableProperty]
+        public partial string StatusMessage { get; set; } = string.Empty;
+
+        [RelayCommand]
+        private void AddParameter()
+        {
+            Parameters.Add(new ParameterEditorRowViewModel(new Parameter { Name = "param" }));
+            StatusMessage = string.Empty;
+        }
+
+        [RelayCommand]
+        private void RemoveParameter(ParameterEditorRowViewModel? row)
+        {
+            if (row is not null)
+            {
+                _ = Parameters.Remove(row);
+                StatusMessage = string.Empty;
+            }
+        }
+
+        public List<Parameter> BuildParameters() => [.. Parameters.Select(r => r.BuildParameter())];
+    }
+}
diff --git a/src/Snipdeck.Core/ViewModels/ShellViewModel.cs b/src/Snipdeck.Core/ViewModels/ShellViewModel.cs
index bd8668a..493b24a 100644
--- a/src/Snipdeck.Core/ViewModels/ShellViewModel.cs
+++ b/src/Snipdeck.Core/ViewModels/ShellViewModel.cs
@@ -86,6 +86,25 @@ public void OpenTrash()
             CurrentContent = BuildTrashViewModel();
         }
 
+        public void OpenGlobalParameters()
+        {
+            CurrentContent = new GlobalParametersViewModel(_document.GlobalParameters);
+        }
+
+        [RelayCommand]
+        private async Task SaveGlobalParametersAsync()
+        {
+            if (CurrentContent is not GlobalParametersViewModel globals)
+            {
+                return;
+            }
+            // Global parameters only affect fill-time resolution (read from the
+            // document on copy), so no shell rebuild is needed — just persist.
+            _document.GlobalParameters = globals.BuildParameters();
+            await _store.SaveAsync(_document).ConfigureAwait(true);
+            globals.StatusMessage = "Saved.";
+        }
+
         public void GoHome()
         {
             SelectedCliChoice = CliChoices.FirstOrDefault(c => c.IsHome);
diff --git a/tests/Snipdeck.Core.Tests/ViewModels/CliEditorViewModelTests.cs b/tests/Snipdeck.Core.Tests/ViewModels/CliEditorViewModelTests.cs
index b20448f..52062d5 100644
--- a/tests/Snipdeck.Core.Tests/ViewModels/CliEditorViewModelTests.cs
+++ b/tests/Snipdeck.Core.Tests/ViewModels/CliEditorViewModelTests.cs
@@ -19,9 +19,9 @@ public void BuildUpdatedCli_applies_the_edited_name_and_keeps_id_and_icon()
         }
 
         [Fact]
-        public void BuildUpdatedCli_preserves_shared_parameters()
+        public void Loads_and_rebuilds_shared_parameters_through_editor_rows()
         {
-            // A rename/icon edit must not drop CLI-scoped parameter definitions.
+            // Existing CLI params load into editor rows and round-trip on save.
             var cli = new Cli
             {
                 Name = "pl-app",
@@ -29,12 +29,27 @@ public void BuildUpdatedCli_preserves_shared_parameters()
             };
             var vm = new CliEditorViewModel(cli) { Name = "renamed" };
 
-            var updated = vm.BuildUpdatedCli();
+            Assert.Equal("env", Assert.Single(vm.Parameters).Name);
 
+            var updated = vm.BuildUpdatedCli();
             var p = Assert.Single(updated.Parameters);
             Assert.Equal("env", p.Name);
             Assert.Equal(ParameterType.Choice, p.Type);
             Assert.Equal(["dev", "prod"], p.Options);
         }
+
+        [Fact]
+        public void Add_and_remove_parameter_rows_reflect_in_the_built_cli()
+        {
+            var vm = new CliEditorViewModel(new Cli { Name = "pl-app" });
+            Assert.Empty(vm.Parameters);
+
+            vm.AddParameter();
+            vm.Parameters[0].Name = "region";
+            Assert.Single(vm.BuildUpdatedCli().Parameters);
+
+            vm.RemoveParameter(vm.Parameters[0]);
+            Assert.Empty(vm.BuildUpdatedCli().Parameters);
+        }
     }
 }
diff --git a/tests/Snipdeck.Core.Tests/ViewModels/GlobalParametersViewModelTests.cs b/tests/Snipdeck.Core.Tests/ViewModels/GlobalParametersViewModelTests.cs
new file mode 100644
index 0000000..20014cc
--- /dev/null
+++ b/tests/Snipdeck.Core.Tests/ViewModels/GlobalParametersViewModelTests.cs
@@ -0,0 +1,42 @@
+using Snipdeck.Core.Models;
+using Snipdeck.Core.ViewModels;
+
+namespace Snipdeck.Core.Tests.ViewModels
+{
+    public class GlobalParametersViewModelTests
+    {
+        [Fact]
+        public void Loads_existing_global_parameters_into_rows()
+        {
+            var vm = new GlobalParametersViewModel([new Parameter { Name = "tenant" }]);
+            Assert.Equal("tenant", Assert.Single(vm.Parameters).Name);
+        }
+
+        [Fact]
+        public void Add_then_build_yields_the_new_parameter()
+        {
+            var vm = new GlobalParametersViewModel([]);
+
+            vm.AddParameterCommand.Execute(null);
+            vm.Parameters[0].Name = "yes_no";
+            vm.Parameters[0].TypeIndex = 1; // Choice
+            vm.Parameters[0].OptionsText = "yes, no";
+
+            var built = vm.BuildParameters();
+            var p = Assert.Single(built);
+            Assert.Equal("yes_no", p.Name);
+            Assert.Equal(ParameterType.Choice, p.Type);
+            Assert.Equal(["yes", "no"], p.Options);
+        }
+
+        [Fact]
+        public void Remove_drops_the_row()
+        {
+            var vm = new GlobalParametersViewModel([new Parameter { Name = "a" }, new Parameter { Name = "b" }]);
+
+            vm.RemoveParameterCommand.Execute(vm.Parameters[0]);
+
+            Assert.Equal("b", Assert.Single(vm.Parameters).Name);
+        }
+    }
+}
diff --git a/tests/Snipdeck.Core.Tests/ViewModels/ShellViewModelCommandsTests.cs b/tests/Snipdeck.Core.Tests/ViewModels/ShellViewModelCommandsTests.cs
index f7c9b1d..c9361a4 100644
--- a/tests/Snipdeck.Core.Tests/ViewModels/ShellViewModelCommandsTests.cs
+++ b/tests/Snipdeck.Core.Tests/ViewModels/ShellViewModelCommandsTests.cs
@@ -334,6 +334,25 @@ public async Task DeleteCurrentCli_no_ops_on_home()
             Assert.Equal(0, store.SaveCount);
         }
 
+        [Fact]
+        public async Task SaveGlobalParameters_persists_edited_rows_to_the_document()
+        {
+            var (vm, store, _, _, _) = await BuildAsync();
+
+            vm.OpenGlobalParameters();
+            var globals = Assert.IsType<GlobalParametersViewModel>(vm.CurrentContent);
+            globals.AddParameterCommand.Execute(null);
+            globals.Parameters[0].Name = "tenant";
+            globals.Parameters[0].Default = "acme";
+
+            await vm.SaveGlobalParametersCommand.ExecuteAsync(null);
+
+            var saved = Assert.Single(store.Document.GlobalParameters);
+            Assert.Equal("tenant", saved.Name);
+            Assert.Equal("acme", saved.Default);
+            Assert.Equal("Saved.", globals.StatusMessage);
+        }
+
         [Fact]
         public async Task OpenTrash_shows_only_trashed_snips()
         {