fix(installer): expand ~ in UiDbPath

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/ClaudeDo.Installer/App.xaml.cs

@@ -110,14 +110,16 @@ public partial class App : Application
         sc.AddSingleton<IInstallStep, WriteConfigStep>();
         sc.AddSingleton<IInstallStep, InitDatabaseStep>();
         sc.AddSingleton<IInstallStep, RegisterServiceStep>();
+        sc.AddSingleton<IInstallStep>(sp => sp.GetRequiredService<StartServiceStep>());
         sc.AddSingleton<IInstallStep, CreateShortcutsStep>();
         sc.AddSingleton<IInstallStep, WriteUninstallRegistryStep>();
         sc.AddSingleton<WriteInstallManifestStep>();
         sc.AddSingleton<IInstallStep>(sp => sp.GetRequiredService<WriteInstallManifestStep>());
 
-        // Stop/Start — NOT registered as IInstallStep (not part of default FreshInstall pipeline).
+        // Stop — NOT registered as IInstallStep (not part of default FreshInstall pipeline).
         // Pulled by Update flow + Repair/Uninstall.
         sc.AddSingleton<StopServiceStep>();
+        // StartServiceStep is also registered as IInstallStep above (fresh-install pipeline).
         sc.AddSingleton<StartServiceStep>();
 
         // Runners

src/ClaudeDo.Installer/Core/UninstallRunner.cs

@@ -17,7 +17,7 @@ public sealed class UninstallRunner
         _stopService = stopService;
     }
 
-    public async Task<StepResult> RunAsync(IProgress<string> progress, CancellationToken ct)
+    public async Task<StepResult> RunAsync(bool removeAppData, IProgress<string> progress, CancellationToken ct)
     {
         // 1) Validate install dir up front — refuse obviously unsafe paths.
         //    Prevents Directory.Delete(recursive:true) from wiping C:\ or C:\Program Files\.
@@ -67,7 +67,9 @@ public sealed class UninstallRunner
                 failures.Add($"install dir ({_context.InstallDirectory}): {err}");
         }
 
-        // 6) Delete ~/.todo-app (config + DB + logs) — user opted into full removal.
+        // 6) Delete ~/.todo-app (config + DB + logs) — only if user opted in.
+        if (removeAppData)
+        {
             var appData = Paths.AppDataRoot();
             if (Directory.Exists(appData))
             {
@@ -75,6 +77,7 @@ public sealed class UninstallRunner
                 if (!TryDeleteDir(appData, out var err))
                     failures.Add($"app data ({appData}): {err}");
             }
+        }
 
         // 7) If we were launched from inside the install dir (Apps & Features case),
         //    our own exe is still locked — schedule a cmd.exe trampoline to finish

src/ClaudeDo.Installer/Steps/DownloadAndExtractStep.cs

@@ -70,11 +70,16 @@ public sealed class DownloadAndExtractStep : IInstallStep
                 return StepResult.Fail("Checksum mismatch — the downloaded zip may be corrupt or tampered with.");
 
             // Only after verification do we touch the install directory.
-            progress.Report("Clearing previous app/worker binaries...");
+            progress.Report("Stashing previous app/worker binaries...");
             var appDest = Path.Combine(ctx.InstallDirectory, "app");
             var workerDest = Path.Combine(ctx.InstallDirectory, "worker");
-            if (Directory.Exists(appDest)) Directory.Delete(appDest, recursive: true);
-            if (Directory.Exists(workerDest)) Directory.Delete(workerDest, recursive: true);
+            var appBak = appDest + ".bak";
+            var workerBak = workerDest + ".bak";
+
+            if (Directory.Exists(appBak))    Directory.Delete(appBak, recursive: true);
+            if (Directory.Exists(workerBak)) Directory.Delete(workerBak, recursive: true);
+            if (Directory.Exists(appDest))   Directory.Move(appDest, appBak);
+            if (Directory.Exists(workerDest)) Directory.Move(workerDest, workerBak);
 
             progress.Report("Extracting...");
             Directory.CreateDirectory(ctx.InstallDirectory);
@@ -84,11 +89,19 @@ public sealed class DownloadAndExtractStep : IInstallStep
             }
             catch (Exception ex)
             {
+                // Roll back to previous binaries.
+                if (Directory.Exists(appDest))   Directory.Delete(appDest, recursive: true);
+                if (Directory.Exists(workerDest)) Directory.Delete(workerDest, recursive: true);
+                if (Directory.Exists(appBak))    Directory.Move(appBak, appDest);
+                if (Directory.Exists(workerBak)) Directory.Move(workerBak, workerDest);
                 return StepResult.Fail(
-                    $"Extraction failed after old binaries were removed: {ex.Message}. " +
-                    "Your install directory may be incomplete. Re-run the installer to retry.");
+                    $"Extraction failed; previous binaries have been restored: {ex.Message}.");
             }
 
+            // Success — drop stash.
+            if (Directory.Exists(appBak))    Directory.Delete(appBak, recursive: true);
+            if (Directory.Exists(workerBak)) Directory.Delete(workerBak, recursive: true);
+
             ctx.InstalledVersion = release.TagName.TrimStart('v', 'V');
             return StepResult.Ok();
         }

src/ClaudeDo.Installer/Steps/RegisterServiceStep.cs

@@ -46,10 +46,9 @@ public sealed class RegisterServiceStep : IInstallStep
         var createArgs = $"create {ServiceName} binPath= \"{workerExe}\" start= {startType}";
 
         if (ctx.ServiceAccount == "CurrentUser")
-        {
-            var username = Environment.UserName;
-            createArgs += $" obj= \".\\{username}\"";
-        }
+            return StepResult.Fail(
+                "Service cannot run as Current User without a password. " +
+                "Select 'Local System' or extend ServicePage to capture a password.");
 
         progress.Report("Creating service...");
         var (exitCode, output) = await RunSc(createArgs, ctx, progress, ct);
@@ -68,15 +67,6 @@ public sealed class RegisterServiceStep : IInstallStep
         if (failExit != 0)
             progress.Report($"Warning: failed to set restart policy (exit {failExit})");
 
-        // Start service if auto-start
-        if (ctx.AutoStart)
-        {
-            progress.Report("Starting service...");
-            var (startExit, _) = await RunSc($"start {ServiceName}", ctx, progress, ct);
-            if (startExit != 0)
-                progress.Report("Warning: service created but failed to start. You may need to start it manually.");
-        }
-
         return StepResult.Ok();
     }
 

src/ClaudeDo.Installer/Steps/WriteConfigStep.cs

@@ -29,7 +29,7 @@ public sealed class WriteConfigStep : IInstallStep
 
             var uiCfg = new InstallerAppSettings
             {
-                DbPath = ctx.UiDbPath,
+                DbPath = Paths.Expand(ctx.UiDbPath),
                 SignalRUrl = ctx.SignalRUrl,
             };
             uiCfg.Save();

src/ClaudeDo.Installer/Views/SettingsViewModel.cs

@@ -29,6 +29,9 @@ public partial class SettingsViewModel : ObservableObject
     [ObservableProperty]
     private string _versionLabel = "";
 
+    [ObservableProperty]
+    private bool _removeAppData;
+
     public SettingsViewModel(
         PageResolver resolver,
         InstallContext context,
@@ -133,8 +136,12 @@ public partial class SettingsViewModel : ObservableObject
     [RelayCommand]
     private async Task Uninstall()
     {
+        var dataNote = RemoveAppData
+            ? "This will remove ClaudeDo AND delete all of your tasks, configuration, and database.\n\nContinue?"
+            : "This will remove ClaudeDo. Your tasks, configuration, and database in ~/.todo-app will be kept.\n\nContinue?";
+
         var confirm = MessageBox.Show(
-            "This will remove ClaudeDo AND delete all of your tasks, configuration, and database.\n\nContinue?",
+            dataNote,
             "Uninstall ClaudeDo",
             MessageBoxButton.YesNo,
             MessageBoxImage.Warning);
@@ -142,7 +149,7 @@ public partial class SettingsViewModel : ObservableObject
         if (confirm != MessageBoxResult.Yes) return;
 
         var progress = new Progress<string>(msg => StatusMessage = msg);
-        var r = await _uninstallRunner.RunAsync(progress, CancellationToken.None);
+        var r = await _uninstallRunner.RunAsync(RemoveAppData, progress, CancellationToken.None);
 
         if (!r.Success)
         {

src/ClaudeDo.Installer/Views/SettingsWindow.xaml

@@ -69,6 +69,7 @@
                     <ColumnDefinition Width="Auto"/>
                     <ColumnDefinition Width="Auto"/>
                     <ColumnDefinition Width="Auto"/>
+                    <ColumnDefinition Width="Auto"/>
                 </Grid.ColumnDefinitions>
 
                 <!-- Status message / version label -->
@@ -88,14 +89,17 @@
                     </TextBlock>
                 </StackPanel>
 
-                <Button Grid.Column="1" Content="Uninstall" Margin="0,0,8,0"
+                <CheckBox Grid.Column="1" IsChecked="{Binding RemoveAppData}"
+                          Content="Remove user data (tasks, logs, configs in ~/.todo-app)"
+                          Margin="0,0,12,0" VerticalAlignment="Center"/>
+                <Button Grid.Column="2" Content="Uninstall" Margin="0,0,8,0"
                         Command="{Binding UninstallCommand}"/>
-                <Button Grid.Column="2" Content="Repair" Margin="0,0,8,0"
+                <Button Grid.Column="3" Content="Repair" Margin="0,0,8,0"
                         Command="{Binding RepairCommand}"/>
-                <Button Grid.Column="3" Content="Save" Margin="0,0,8,0"
+                <Button Grid.Column="4" Content="Save" Margin="0,0,8,0"
                         Command="{Binding SaveCommand}"
                         Style="{StaticResource AccentButton}"/>
-                <Button Grid.Column="4" Content="Close"
+                <Button Grid.Column="5" Content="Close"
                         Command="{Binding CloseCommand}"/>
             </Grid>
         </Border>

src/ClaudeDo.Ui/ViewModels/ListEditorViewModel.cs

@@ -54,6 +54,7 @@ public partial class ListEditorViewModel : ViewModelBase
 
     public void InitForCreate()
     {
+        _tcs = new TaskCompletionSource<ListEntity?>();
         _editId = null;
         _createdAt = DateTime.UtcNow;
         WindowTitle = "New List";
@@ -61,6 +62,7 @@ public partial class ListEditorViewModel : ViewModelBase
 
     public void InitForEdit(ListEntity entity, ListConfigEntity? config)
     {
+        _tcs = new TaskCompletionSource<ListEntity?>();
         _editId = entity.Id;
         _createdAt = entity.CreatedAt;
         Name = entity.Name;
@@ -119,9 +121,5 @@ public partial class ListEditorViewModel : ViewModelBase
         _tcs.TrySetResult(null);
     }
 
-    public Task<ListEntity?> ShowAndWaitAsync()
-    {
-        _tcs = new TaskCompletionSource<ListEntity?>();
-        return _tcs.Task;
-    }
+    public Task<ListEntity?> ShowAndWaitAsync() => _tcs.Task;
 }

src/ClaudeDo.Ui/ViewModels/TaskDetailViewModel.cs

@@ -85,6 +85,12 @@ public partial class TaskDetailViewModel : ViewModelBase
         var ct = cts.Token;
 
         _taskId = taskId;
+        HasWorktree = false;
+        WorktreeState = "";
+        BranchName = null;
+        DiffStat = null;
+        WorktreePath = null;
+        OnPropertyChanged(nameof(CanWorktreeAction));
         LiveText = "";
         _formatter = new StreamLineFormatter();
 

src/ClaudeDo.Ui/ViewModels/TaskEditorViewModel.cs

@@ -71,6 +71,7 @@ public partial class TaskEditorViewModel : ViewModelBase
 
     public void InitForCreate(string listId, string defaultCommitType = "chore")
     {
+        _tcs = new TaskCompletionSource<TaskEntity?>();
         _editId = null;
         _listId = listId;
         _createdAt = DateTime.UtcNow;
@@ -81,6 +82,7 @@ public partial class TaskEditorViewModel : ViewModelBase
 
     public async Task InitForEditAsync(TaskEntity entity, IReadOnlyList<TagEntity> taskTags, CancellationToken ct = default)
     {
+        _tcs = new TaskCompletionSource<TaskEntity?>();
         _editId = entity.Id;
         _listId = entity.ListId;
         _createdAt = entity.CreatedAt;
@@ -128,6 +130,7 @@ public partial class TaskEditorViewModel : ViewModelBase
     // Keep old sync overload for callers that haven't loaded agents yet
     public void InitForEdit(TaskEntity entity, IReadOnlyList<TagEntity> taskTags)
     {
+        _tcs = new TaskCompletionSource<TaskEntity?>();
         _editId = entity.Id;
         _listId = entity.ListId;
         _createdAt = entity.CreatedAt;
@@ -257,9 +260,5 @@ public partial class TaskEditorViewModel : ViewModelBase
         _tcs.TrySetResult(null);
     }
 
-    public Task<TaskEntity?> ShowAndWaitAsync()
-    {
-        _tcs = new TaskCompletionSource<TaskEntity?>();
-        return _tcs.Task;
-    }
+    public Task<TaskEntity?> ShowAndWaitAsync() => _tcs.Task;
 }

src/ClaudeDo.Ui/ViewModels/TaskListViewModel.cs

@@ -157,17 +157,20 @@ public partial class TaskListViewModel : ViewModelBase
     [RelayCommand(CanExecute = nameof(CanAddTask))]
     private async Task AddTask()
     {
+        var listId = CurrentListId;
+        if (listId is null) return;
+
         string defaultCommitType;
         using (var context = _dbFactory.CreateDbContext())
         {
             var listRepo = new ListRepository(context);
-            var list = await listRepo.GetByIdAsync(CurrentListId);
+            var list = await listRepo.GetByIdAsync(listId);
             defaultCommitType = list?.DefaultCommitType ?? "chore";
         }
 
         var editor = _editorFactory();
         await editor.LoadAgentsAsync(_worker);
-        editor.InitForCreate(CurrentListId, defaultCommitType);
+        editor.InitForCreate(listId, defaultCommitType);
 
         var window = new TaskEditorView { DataContext = editor };
         editor.RequestClose += () => window.Close();
@@ -328,8 +331,15 @@ public partial class TaskListViewModel : ViewModelBase
     private async void OnTaskUpdated(string taskId)
     {
         if (CurrentListId is null) return;
+        try
+        {
             await RefreshSingleAsync(taskId);
         }
+        catch (Exception ex)
+        {
+            System.Diagnostics.Debug.WriteLine($"[TaskListViewModel] OnTaskUpdated failed for {taskId}: {ex}");
+        }
+    }
 
     private static async Task ShowDialogAsync(Window dialog)
     {

src/ClaudeDo.Worker/Hub/WorkerHub.cs

@@ -37,7 +37,6 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         try
         {
             await _queue.RunNow(taskId);
-            await _broadcaster.RunCreated(taskId, 1, false);
         }
         catch (InvalidOperationException)
         {

src/ClaudeDo.Worker/Runner/ClaudeArgsBuilder.cs

@@ -55,9 +55,15 @@ public sealed class ClaudeArgsBuilder
 
     private static string Escape(string value)
     {
-        if (value.Contains(' ') || value.Contains('"') || value.Contains('\''))
+        if (value.Contains(' ') || value.Contains('"') || value.Contains('\'')
+            || value.Contains('\t') || value.Contains('\n') || value.Contains('\r'))
         {
-            var escaped = value.Replace("\\", "\\\\").Replace("\"", "\\\"");
+            var escaped = value
+                .Replace("\\", "\\\\")
+                .Replace("\"", "\\\"")
+                .Replace("\n", "\\n")
+                .Replace("\r", "\\r")
+                .Replace("\t", "\\t");
             return $"\"{escaped}\"";
         }
         return value;

src/ClaudeDo.Worker/Runner/TaskRunner.cs

@@ -125,7 +125,6 @@ public sealed class TaskRunner
                     var retryConfig = resolvedConfig with { ResumeSessionId = result.SessionId };
                     var retryPrompt = $"The previous attempt failed with:\n\n{result.ErrorMarkdown}\n\nTry again and fix the issues.";
 
-                    await _broadcaster.RunCreated(task.Id, 2, true);
                     var retryResult = await RunOnceAsync(task.Id, slot, runDir, retryConfig, 2, true, retryPrompt, ct);
 
                     if (retryResult.IsSuccess)
@@ -216,7 +215,6 @@ public sealed class TaskRunner
         await _broadcaster.TaskStarted(slot, taskId, now);
 
         var nextRunNumber = lastRun.RunNumber + 1;
-        await _broadcaster.RunCreated(taskId, nextRunNumber, false);
         var result = await RunOnceAsync(taskId, slot, runDir, resolvedConfig, nextRunNumber, false, followUpPrompt, ct);
 
         if (result.IsSuccess)
@@ -255,6 +253,8 @@ public sealed class TaskRunner
             await runRepo.AddAsync(run, ct);
         }
 
+        await _broadcaster.RunCreated(taskId, runNumber, isRetry);
+
         var arguments = _argsBuilder.Build(config);
 
         await using var logWriter = new LogWriter(logPath);

src/ClaudeDo.Worker/Services/QueueService.cs

@@ -68,6 +68,8 @@ public sealed class QueueService : BackgroundService
 
         lock (_lock)
         {
+            if (_queueSlot?.TaskId == taskId)
+                throw new InvalidOperationException("task is already running in queue slot");
             if (_overrideSlot is not null)
                 throw new InvalidOperationException("override slot busy");
 
@@ -92,10 +94,12 @@ public sealed class QueueService : BackgroundService
             ?? throw new KeyNotFoundException($"Task '{taskId}' not found.");
 
         if (task.Status == Data.Models.TaskStatus.Running)
-            throw new InvalidOperationException("Task is currently running.");
+            throw new InvalidOperationException("task is already running");
 
         lock (_lock)
         {
+            if (_queueSlot?.TaskId == taskId)
+                throw new InvalidOperationException("task is already running in queue slot");
             if (_overrideSlot is not null)
                 throw new InvalidOperationException("override slot busy");
 

tests/ClaudeDo.Worker.Tests/Runner/ClaudeArgsBuilderTests.cs

@@ -68,4 +68,28 @@ public sealed class ClaudeArgsBuilderTests
         var args = _builder.Build(new ClaudeRunConfig(null, """Don't say "hello".""", null, null));
         Assert.Contains("--append-system-prompt", args);
     }
+
+    [Fact]
+    public void Build_quotes_system_prompt_with_newline()
+    {
+        var args = _builder.Build(new ClaudeRunConfig(
+            Model: null,
+            SystemPrompt: "line1\nline2",
+            AgentPath: null,
+            ResumeSessionId: null));
+
+        Assert.Contains("--append-system-prompt \"line1\\nline2\"", args);
+    }
+
+    [Fact]
+    public void Build_quotes_system_prompt_with_tab()
+    {
+        var args = _builder.Build(new ClaudeRunConfig(
+            Model: null,
+            SystemPrompt: "col1\tcol2",
+            AgentPath: null,
+            ResumeSessionId: null));
+
+        Assert.Contains("\"col1", args);
+    }
 }

tests/ClaudeDo.Worker.Tests/Services/QueueServiceSlotGuardTests.cs

@@ -0,0 +1,146 @@
+using ClaudeDo.Data;
+using ClaudeDo.Data.Models;
+using ClaudeDo.Data.Repositories;
+using ClaudeDo.Worker.Config;
+using ClaudeDo.Worker.Hub;
+using ClaudeDo.Worker.Runner;
+using ClaudeDo.Worker.Services;
+using ClaudeDo.Worker.Tests.Infrastructure;
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.Extensions.Logging.Abstractions;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Worker.Tests.Services;
+
+public sealed class QueueServiceSlotGuardTests : IDisposable
+{
+    private readonly DbFixture _db = new();
+    private readonly ClaudeDoDbContext _ctx;
+    private readonly TaskRepository _taskRepo;
+    private readonly ListRepository _listRepo;
+    private readonly TagRepository _tagRepo;
+    private readonly WorkerConfig _cfg;
+    private readonly string _tempDir;
+
+    public QueueServiceSlotGuardTests()
+    {
+        _ctx = _db.CreateContext();
+        _taskRepo = new TaskRepository(_ctx);
+        _listRepo = new ListRepository(_ctx);
+        _tagRepo = new TagRepository(_ctx);
+        _tempDir = Path.Combine(Path.GetTempPath(), $"claudedo_slotguard_{Guid.NewGuid():N}");
+        Directory.CreateDirectory(_tempDir);
+        _cfg = new WorkerConfig
+        {
+            SandboxRoot = Path.Combine(_tempDir, "sandbox"),
+            LogRoot = Path.Combine(_tempDir, "logs"),
+            QueueBackstopIntervalMs = 50,
+        };
+    }
+
+    public void Dispose()
+    {
+        _ctx.Dispose();
+        _db.Dispose();
+        try { Directory.Delete(_tempDir, true); } catch { }
+    }
+
+    private (QueueService service, FakeClaudeProcess fakeProcess) CreateService(
+        Func<string, string, string, Func<string, Task>, CancellationToken, Task<RunResult>>? handler = null)
+    {
+        var fake = new FakeClaudeProcess(handler);
+        var broadcaster = new HubBroadcaster(new FakeHubContext());
+        var dbFactory = _db.CreateFactory();
+        var wtManager = new WorktreeManager(new ClaudeDo.Data.Git.GitService(), dbFactory, _cfg, NullLogger<WorktreeManager>.Instance);
+        var argsBuilder = new ClaudeArgsBuilder();
+        var runner = new TaskRunner(fake, dbFactory, broadcaster, wtManager, argsBuilder, _cfg,
+            NullLogger<TaskRunner>.Instance);
+        var service = new QueueService(dbFactory, runner, _cfg, NullLogger<QueueService>.Instance);
+        return (service, fake);
+    }
+
+    private async Task<string> SeedListWithAgentTagAsync()
+    {
+        var listId = Guid.NewGuid().ToString();
+        await _listRepo.AddAsync(new ListEntity { Id = listId, Name = "Test", CreatedAt = DateTime.UtcNow });
+        var tags = await _tagRepo.GetAllAsync();
+        var agentTag = tags.First(t => t.Name == "agent");
+        await _listRepo.AddTagAsync(listId, agentTag.Id);
+        return listId;
+    }
+
+    private async Task<TaskEntity> SeedQueuedTaskAsync(string listId)
+    {
+        var task = new TaskEntity
+        {
+            Id = Guid.NewGuid().ToString(),
+            ListId = listId,
+            Title = "Guard test task",
+            Description = "Test",
+            Status = TaskStatus.Queued,
+            CreatedAt = DateTime.UtcNow,
+        };
+        await _taskRepo.AddAsync(task);
+        return task;
+    }
+
+    [Fact]
+    public async Task RunNow_Throws_When_Task_Already_Running_In_Queue_Slot()
+    {
+        var listId = await SeedListWithAgentTagAsync();
+        var task = await SeedQueuedTaskAsync(listId);
+
+        // Gate keeps the queue slot occupied indefinitely.
+        var tcs = new TaskCompletionSource<RunResult>();
+        var queuePickedUp = new TaskCompletionSource();
+
+        var (service, _) = CreateService(async (_, _, _, _, ct) =>
+        {
+            queuePickedUp.TrySetResult();
+            return await tcs.Task;
+        });
+
+        using var cts = new CancellationTokenSource();
+        await service.StartAsync(cts.Token);
+        service.WakeQueue();
+
+        // Wait until the queue slot has actually picked up the task.
+        await queuePickedUp.Task.WaitAsync(TimeSpan.FromSeconds(5));
+
+        // Now the same taskId is in the queue slot — RunNow must reject it.
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() => service.RunNow(task.Id));
+        Assert.Contains("already running", ex.Message);
+
+        tcs.SetResult(new RunResult { ExitCode = 0, ResultMarkdown = "ok" });
+        cts.Cancel();
+    }
+
+    [Fact]
+    public async Task ContinueTask_Throws_When_Task_Already_Running_In_Queue_Slot()
+    {
+        var listId = await SeedListWithAgentTagAsync();
+        var task = await SeedQueuedTaskAsync(listId);
+
+        var tcs = new TaskCompletionSource<RunResult>();
+        var queuePickedUp = new TaskCompletionSource();
+
+        var (service, _) = CreateService(async (_, _, _, _, ct) =>
+        {
+            queuePickedUp.TrySetResult();
+            return await tcs.Task;
+        });
+
+        using var cts = new CancellationTokenSource();
+        await service.StartAsync(cts.Token);
+        service.WakeQueue();
+
+        await queuePickedUp.Task.WaitAsync(TimeSpan.FromSeconds(5));
+
+        var ex = await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            service.ContinueTask(task.Id, "follow-up"));
+        Assert.Contains("already running", ex.Message);
+
+        tcs.SetResult(new RunResult { ExitCode = 0, ResultMarkdown = "ok" });
+        cts.Cancel();
+    }
+}