From bcc505ce0f956d80d65d9c972b436c1c4098f376 Mon Sep 17 00:00:00 2001
From: James Montemagno <james.montemagno@gmail.com>
Date: Sat, 18 Jul 2026 22:10:39 -0700
Subject: [PATCH] Update Copilot SDK model selection

---
 src/MauiSherpa.Core/Interfaces.cs             | 12 +++
 src/MauiSherpa.Core/MauiSherpa.Core.csproj    |  2 +-
 .../Services/CopilotService.cs                | 29 ++++++-
 src/MauiSherpa.MacOS/MauiSherpa.MacOS.csproj  |  2 +-
 src/MauiSherpa/Pages/Copilot.razor            | 83 ++++++++++++++++++-
 5 files changed, 122 insertions(+), 6 deletions(-)

diff --git a/src/MauiSherpa.Core/Interfaces.cs b/src/MauiSherpa.Core/Interfaces.cs
index 26124afa..4734c8c7 100644
--- a/src/MauiSherpa.Core/Interfaces.cs
+++ b/src/MauiSherpa.Core/Interfaces.cs
@@ -2510,6 +2510,8 @@ Task<MultiOperationResult> RunAsync(
     event Action? OnModalClosed;
 }
 
+public sealed record CopilotModelOption(string Id, string Name);
+
 /// <summary>
 /// Service for interacting with GitHub Copilot
 /// </summary>
@@ -2550,6 +2552,16 @@ public interface ICopilotService
     /// </summary>
     /// <param name="model">Optional model to use</param>
     Task StartSessionAsync(string? model = null, string? systemPrompt = null);
+
+    /// <summary>
+    /// Get the models available to the authenticated user.
+    /// </summary>
+    Task<IReadOnlyList<CopilotModelOption>> ListModelsAsync();
+
+    /// <summary>
+    /// Change the model for the active chat session.
+    /// </summary>
+    Task SetModelAsync(string model);
     
     /// <summary>
     /// End the current chat session
diff --git a/src/MauiSherpa.Core/MauiSherpa.Core.csproj b/src/MauiSherpa.Core/MauiSherpa.Core.csproj
index 38af9e3e..2451bf8b 100644
--- a/src/MauiSherpa.Core/MauiSherpa.Core.csproj
+++ b/src/MauiSherpa.Core/MauiSherpa.Core.csproj
@@ -38,7 +38,7 @@
     <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="10.0.9" />
     <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="10.0.9" />
     <PackageReference Include="FluentValidation" Version="12.1.1" />
-    <PackageReference Include="GitHub.Copilot.SDK" Version="1.0.3" />
+    <PackageReference Include="GitHub.Copilot.SDK" Version="1.0.7" />
     <PackageReference Include="Microsoft.TeamFoundation.DistributedTask.WebApi" Version="19.225.2" />
     <PackageReference Include="Microsoft.TeamFoundationServer.Client" Version="19.225.2" />
     <PackageReference Include="Microsoft.VisualStudio.Services.Client" Version="19.225.2" />
diff --git a/src/MauiSherpa.Core/Services/CopilotService.cs b/src/MauiSherpa.Core/Services/CopilotService.cs
index 3b0c186f..3e9d4c1e 100644
--- a/src/MauiSherpa.Core/Services/CopilotService.cs
+++ b/src/MauiSherpa.Core/Services/CopilotService.cs
@@ -598,7 +598,8 @@ public async Task StartSessionAsync(string? model = null, string? systemPrompt =
 
         try
         {
-            _logger.LogInformation($"Starting Copilot session with model: {model ?? "default"}");
+            var selectedModel = string.IsNullOrWhiteSpace(model) ? "auto" : model;
+            _logger.LogInformation($"Starting Copilot session with model: {selectedModel}");
             
             // Get tools from tools service
             var tools = _toolsService.GetTools();
@@ -609,7 +610,7 @@ public async Task StartSessionAsync(string? model = null, string? systemPrompt =
             
             var config = new SessionConfig
             {
-                Model = model ?? "claude-opus-4.5", // Use Claude Opus 4.5 as default
+                Model = selectedModel,
                 Streaming = true,
                 Tools = tools.Cast<AIFunctionDeclaration>().ToList(),
                 OnPermissionRequest = HandleSdkPermissionRequest,
@@ -657,6 +658,30 @@ public async Task StartSessionAsync(string? model = null, string? systemPrompt =
             throw;
         }
     }
+
+    public async Task<IReadOnlyList<CopilotModelOption>> ListModelsAsync()
+    {
+        if (_client == null)
+        {
+            throw new InvalidOperationException("Not connected to Copilot. Call ConnectAsync first.");
+        }
+
+        var models = await _client.ListModelsAsync();
+        return models
+            .Select(model => new CopilotModelOption(model.Id, model.Name ?? model.Id))
+            .ToList();
+    }
+
+    public async Task SetModelAsync(string model)
+    {
+        if (_session == null)
+        {
+            throw new InvalidOperationException("No active Copilot session. Call StartSessionAsync first.");
+        }
+
+        await _session.SetModelAsync(model);
+        _logger.LogInformation($"Copilot session model changed to: {model}");
+    }
     
 #pragma warning disable GHCP001
     private async Task<GitHub.Copilot.Rpc.PermissionDecision> HandleSdkPermissionRequest(PermissionRequest request, PermissionInvocation invocation)
diff --git a/src/MauiSherpa.MacOS/MauiSherpa.MacOS.csproj b/src/MauiSherpa.MacOS/MauiSherpa.MacOS.csproj
index 926e0f12..dc7f0867 100644
--- a/src/MauiSherpa.MacOS/MauiSherpa.MacOS.csproj
+++ b/src/MauiSherpa.MacOS/MauiSherpa.MacOS.csproj
@@ -35,7 +35,7 @@
     <PackageReference Include="Blazorise.Icons.FontAwesome" Version="1.7.2" />
     <!-- Reference the SDK directly so its build targets run with the AppKit publish RID
          instead of inheriting the build-host architecture from MauiSherpa.Core. -->
-    <PackageReference Include="GitHub.Copilot.SDK" Version="1.0.3" PrivateAssets="all" />
+    <PackageReference Include="GitHub.Copilot.SDK" Version="1.0.7" PrivateAssets="all" />
     <PackageReference Include="Microsoft.AspNetCore.Components.QuickGrid" Version="10.0.1" />
     <PackageReference Include="Markdig" Version="0.44.0" />
     <PackageReference Include="Microsoft.AspNetCore.Components.WebView.Maui" Version="10.0.1" />
diff --git a/src/MauiSherpa/Pages/Copilot.razor b/src/MauiSherpa/Pages/Copilot.razor
index b86b9393..5a0ef701 100644
--- a/src/MauiSherpa/Pages/Copilot.razor
+++ b/src/MauiSherpa/Pages/Copilot.razor
@@ -191,6 +191,15 @@ else
         <div class="chat-layout">
         <!-- Chat Messages -->
         <div class="chat-container">
+            <div class="model-selector">
+                <label for="copilot-model"><i class="fas fa-robot"></i> Model</label>
+                <select id="copilot-model" value="@selectedModel" @onchange="SelectModelAsync" disabled="@isBusy">
+                    @foreach (var model in availableModels)
+                    {
+                        <option value="@model.Id">@model.Name</option>
+                    }
+                </select>
+            </div>
             <div class="chat-messages" @ref="chatMessagesRef" @onscroll="OnChatScroll">
                 @* Show suggestions as first item - collapsible *@
                 <div class="suggestions-bubble @(suggestionsCollapsed ? "collapsed" : "")">
@@ -806,6 +815,34 @@ else
         gap: 1.25rem;
     }
 
+    .model-selector {
+        display: flex;
+        align-items: center;
+        gap: 0.5rem;
+        padding: 0.5rem 0.75rem;
+        border-bottom: 1px solid var(--border-color);
+        color: var(--text-secondary);
+        font-size: 0.8rem;
+    }
+
+    .model-selector label {
+        display: flex;
+        align-items: center;
+        gap: 0.35rem;
+        font-weight: 600;
+    }
+
+    .model-selector select {
+        min-width: 10rem;
+        max-width: 16rem;
+        padding: 0.25rem 0.5rem;
+        border: 1px solid var(--border-color);
+        border-radius: 4px;
+        background: var(--bg-tertiary);
+        color: var(--text-primary);
+        font: inherit;
+    }
+
     .suggestions-section {
         background: var(--card-bg);
         border-radius: 0.75rem;
@@ -2180,6 +2217,8 @@ else
     private CopilotAvailability? availability;
     private bool isConnecting = false;
     private bool isBusy = false;
+    private string selectedModel = "auto";
+    private List<CopilotModelOption> availableModels = [new("auto", "Auto")];
     private bool suggestionsCollapsed = false;
     private string userInput = "";
     private string currentResponse = "";
@@ -2448,7 +2487,8 @@ else
         try
         {
             await CopilotService.ConnectAsync();
-            await CopilotService.StartSessionAsync(systemPrompt: _systemPrompt);
+            await CopilotService.StartSessionAsync(selectedModel, _systemPrompt);
+            await LoadModelsAsync();
             availability = availability is null
                 ? new CopilotAvailability(true, true, null, null, null)
                 : availability with { IsInstalled = true, IsAuthenticated = true, ErrorMessage = null };
@@ -2534,11 +2574,12 @@ else
             if (!CopilotService.IsConnected)
             {
                 await CopilotService.ConnectAsync();
+                await LoadModelsAsync();
             }
 
             if (CopilotService.CurrentSessionId == null)
             {
-                await CopilotService.StartSessionAsync(systemPrompt: _systemPrompt);
+                await CopilotService.StartSessionAsync(selectedModel, _systemPrompt);
             }
 
             await CopilotService.SendMessageAsync(message);
@@ -2553,6 +2594,44 @@ else
         }
     }
 
+    private async Task LoadModelsAsync()
+    {
+        try
+        {
+            var models = await CopilotService.ListModelsAsync();
+            availableModels = [
+                new CopilotModelOption("auto", "Auto"),
+                .. models.Where(model => !string.Equals(model.Id, "auto", StringComparison.OrdinalIgnoreCase))
+            ];
+        }
+        catch (Exception ex)
+        {
+            _logger.LogWarning($"Unable to load Copilot models: {ex.Message}");
+        }
+    }
+
+    private async Task SelectModelAsync(ChangeEventArgs args)
+    {
+        var model = args.Value?.ToString();
+        if (string.IsNullOrWhiteSpace(model) || string.Equals(model, selectedModel, StringComparison.Ordinal))
+            return;
+
+        var previousModel = selectedModel;
+        selectedModel = model;
+
+        try
+        {
+            await CopilotService.SetModelAsync(selectedModel);
+            currentUsageInfo = null;
+        }
+        catch (Exception ex)
+        {
+            selectedModel = previousModel;
+            _logger.LogError($"Unable to change Copilot model: {ex.Message}", ex);
+            await AlertService.ShowAlertAsync("Model Change Failed", ex.Message);
+        }
+    }
+
     private void OnNativeMessageSubmitted(string message)
     {
         InvokeAsync(async () =>