fix: resolve critical bugs and improve reliability across worker, data, UI

- Fix worker using wrong DB by defaulting to CurrentUser service account
  and expanding ~ to absolute paths at install time
- Fix DbContext disposed before fire-and-forget by passing taskId instead
  of TaskEntity into RunInSlotAsync, which creates its own context
- Fix ActiveTaskDto property casing mismatch between hub and client
- Move WAL mode PRAGMA before migrations to prevent concurrent lock issues
- Replace FirstAsync with FirstOrDefaultAsync + null guards in tag operations
- Add delete confirmation flow for lists
- Log fire-and-forget exceptions instead of swallowing them
- Broadcast RunCreated event from WorkerHub.RunNow
- Add IDisposable to MainWindowViewModel for event handler cleanup
- Preserve subtask CreatedAt on updates instead of overwriting
- Replace bare catch blocks with Debug.WriteLine logging

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docs/superpowers/specs/2026-04-16-subtask-tree-view-design.md

@@ -0,0 +1,118 @@
+# Subtask Tree View in Task List
+
+## Problem
+
+Subtasks are invisible in the task list — users only see them after opening the detail pane or editor modal. This makes it hard to get an overview of task progress without clicking into each task individually.
+
+## Solution
+
+Show subtasks indented below their parent task in the task list, with expand/collapse. Tasks start collapsed with a visual indicator when subtasks exist.
+
+## Scope
+
+Pure UI/ViewModel change. No data model changes, no new migrations, no repository schema changes.
+
+## Design
+
+### ViewModel Changes
+
+**TaskItemViewModel** — add:
+
+- `ObservableCollection<SubtaskItemViewModel> Subtasks` — populated on first expand
+- `bool IsExpanded` — observable, default `false`; toggles subtask visibility
+- `bool HasSubtasks` — observable, set during initial load from a count query
+- `int SubtaskCount` — observable, used for the indicator
+- `ToggleExpandedCommand` — flips `IsExpanded`; on first expand, loads subtasks from `SubtaskRepository.GetByTaskIdAsync`
+- `ToggleSubtaskDoneCommand(string subtaskId)` — toggles a subtask's `Completed` and persists via `SubtaskRepository.UpdateAsync`
+
+Constructor gains `SubtaskRepository` and initial `subtaskCount` parameter.
+
+**TaskListViewModel.LoadAsync** — after fetching tasks, run a single batch query to get subtask counts per task. Pass counts into each `TaskItemViewModel`. This avoids N+1 queries on load.
+
+**TaskListViewModel.RefreshSingleAsync** — if the refreshed task's `IsExpanded` is true, also reload its subtasks from DB and update the collection.
+
+### Repository Changes
+
+**SubtaskRepository** — add one method:
+
+```csharp
+Task<Dictionary<string, int>> GetCountsByTaskIdsAsync(IEnumerable<string> taskIds, CancellationToken ct = default)
+```
+
+Single query: `SELECT task_id, COUNT(*) FROM subtasks WHERE task_id IN (...) GROUP BY task_id`. Returns a map of taskId -> count. Tasks with no subtasks won't appear in the result (count defaults to 0).
+
+### XAML Changes
+
+**TaskListView.axaml** — the `DataTemplate` for `TaskItemViewModel` becomes a 2-row grid:
+
+```
+Row 0: [ExpandChevron] [StatusCircle] [Title + Tags/Status subtitle]
+Row 1: [SubtaskItemsControl, margin-left ~40px, visible when IsExpanded]
+```
+
+**Row 0 — Expand chevron:**
+- Column 0 gets a small chevron button (12x12 `Path` data) before the status circle
+- Right-pointing when collapsed, down-pointing when expanded
+- Bound to `ToggleExpandedCommand`
+- Only visible when `HasSubtasks` is true (via `IsVisible` binding)
+- When `HasSubtasks` is false, the space is empty but reserved (fixed-width column) so all titles align
+
+**Row 1 — Subtask list:**
+- `ItemsControl` bound to `Subtasks`
+- `IsVisible` bound to `IsExpanded`
+- Left margin ~40px for visual indentation
+- Each subtask item: `CheckBox` (bound to `Completed`) + `TextBlock` (bound to `Title`)
+- Subtask row has its own context menu flyout with "Edit Task" (opens parent task's editor modal via `EditTaskCommand` on root `TaskListViewModel`)
+- Checkbox toggle calls `ToggleSubtaskDoneCommand` on the parent `TaskItemViewModel`
+
+**Column layout change:** The existing 2-column `Grid` (`Auto, *`) gets a third column prepended: `Auto, Auto, *`. The chevron goes in column 0, status circle in column 1, title stack in column 2. Row 1 spans all 3 columns.
+
+### Subtask Checkbox Interaction
+
+When a subtask checkbox is toggled in the list:
+1. Update the `SubtaskItemViewModel.Completed` property
+2. Call `SubtaskRepository.UpdateAsync` with the updated entity (same auto-save pattern as `TaskDetailView`)
+3. No need to refresh the parent task — subtask completion doesn't affect task status
+
+### Subtask Context Menu
+
+Right-click on a subtask row shows:
+- "Edit Task" — opens the parent task's editor modal (same flow as `EditTaskCommand`)
+
+This reuses the existing editor which already has full subtask editing (add/remove/reorder/rename).
+
+### Real-time Updates
+
+When `RefreshSingleAsync` fires (via SignalR `TaskUpdatedEvent`):
+1. Reload subtask count, update `HasSubtasks` and `SubtaskCount`
+2. If `IsExpanded`, reload subtask list from DB and reconcile with the observable collection
+
+### Detail Pane Sync
+
+When the user edits subtasks in `TaskDetailView` (auto-save) or `TaskEditorView` (batch-save), the list view's subtask state may become stale. Two options:
+
+**Chosen approach:** The detail pane and editor already trigger `TaskUpdatedEvent` (or the editor's save path calls `RefreshSingleAsync` via `SelectedTask.Refresh`). Extend `Refresh` on `TaskItemViewModel` to also reload subtasks if expanded, and update `HasSubtasks`/`SubtaskCount`.
+
+### Visual Style
+
+- Chevron: 10x10 path, `TextDimBrush` color, no background, cursor=Hand
+- Subtask rows: smaller font (12px), `TextDimBrush` for unchecked title, strikethrough + dimmed for completed
+- Subtask checkbox: standard Avalonia `CheckBox` (no custom circular border), small size
+- Subtask row vertical padding: 2px (compact)
+- Indent: 40px left margin on the subtask `ItemsControl`
+
+## Files to Modify
+
+1. `src/ClaudeDo.Data/Repositories/SubtaskRepository.cs` — add `GetCountsByTaskIdsAsync`
+2. `src/ClaudeDo.Ui/ViewModels/TaskItemViewModel.cs` — add subtask collection, expand/collapse, toggle done
+3. `src/ClaudeDo.Ui/ViewModels/TaskListViewModel.cs` — batch-load counts, pass SubtaskRepository, extend refresh
+4. `src/ClaudeDo.Ui/Views/TaskListView.axaml` — restructure item template with chevron + nested ItemsControl
+5. `src/ClaudeDo.Ui/Views/TaskListView.axaml.cs` — handle subtask context menu pointer-pressed if needed
+6. `src/ClaudeDo.App/Program.cs` — pass SubtaskRepository to TaskListViewModel (if not already available via DI)
+
+## Out of Scope
+
+- Drag-to-reorder subtasks in the list view
+- Add subtask directly from the list view
+- Subtask progress indicator (e.g., "2/5 done") on collapsed tasks
+- Recursive task nesting (tasks containing tasks)

src/ClaudeDo.App/Program.cs

@@ -8,14 +8,21 @@ using ClaudeDo.Ui.ViewModels;
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.DependencyInjection;
 using System;
+using System.Runtime.InteropServices;
 
 namespace ClaudeDo.App;
 
 sealed class Program
 {
+    [DllImport("shell32.dll", CharSet = CharSet.Unicode)]
+    private static extern int SetCurrentProcessExplicitAppUserModelID(string appId);
+
     [STAThread]
     public static void Main(string[] args)
     {
+        if (RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
+            SetCurrentProcessExplicitAppUserModelID("ClaudeDo.App");
+
         var services = BuildServices();
         App.Services = services;
 

src/ClaudeDo.Data/ClaudeDoDbContext.cs

@@ -30,10 +30,21 @@ public class ClaudeDoDbContext : DbContext
     /// </summary>
     public static void MigrateAndConfigure(ClaudeDoDbContext db)
     {
+        var conn = db.Database.GetDbConnection();
+        try
+        {
+            conn.Open();
+
+            // Set WAL FIRST, before migrations — prevents write-lock contention
+            // when UI and Worker start simultaneously.
+            using (var walCmd = conn.CreateCommand())
+            {
+                walCmd.CommandText = "PRAGMA journal_mode=wal;";
+                walCmd.ExecuteNonQuery();
+            }
+
             // If the 'lists' table exists but __EFMigrationsHistory does not,
             // this is a pre-EF database. Baseline the InitialCreate migration.
-        var conn = db.Database.GetDbConnection();
-        conn.Open();
             using (var cmd = conn.CreateCommand())
             {
                 cmd.CommandText = "SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='lists'";
@@ -44,7 +55,6 @@ public class ClaudeDoDbContext : DbContext
 
                 if (hasLists && !hasHistory)
                 {
-                // Create the history table and mark InitialCreate as applied.
                     cmd.CommandText = """
                         CREATE TABLE "__EFMigrationsHistory" (
                             "MigrationId" TEXT NOT NULL CONSTRAINT "PK___EFMigrationsHistory" PRIMARY KEY,
@@ -56,9 +66,12 @@ public class ClaudeDoDbContext : DbContext
                     cmd.ExecuteNonQuery();
                 }
             }
+        }
+        finally
+        {
             conn.Close();
+        }
 
         db.Database.Migrate();
-        db.Database.ExecuteSqlRaw("PRAGMA journal_mode=WAL");
     }
 }

src/ClaudeDo.Data/Repositories/ListRepository.cs

@@ -46,7 +46,8 @@ public sealed class ListRepository
 
     public async Task AddTagAsync(string listId, long tagId, CancellationToken ct = default)
     {
-        var list = await _context.Lists.Include(l => l.Tags).FirstAsync(l => l.Id == listId, ct);
+        var list = await _context.Lists.Include(l => l.Tags).FirstOrDefaultAsync(l => l.Id == listId, ct);
+        if (list is null) return;
         var tag = await _context.Tags.FindAsync([tagId], ct);
         if (tag is not null && !list.Tags.Any(t => t.Id == tagId))
         {
@@ -57,7 +58,8 @@ public sealed class ListRepository
 
     public async Task RemoveTagAsync(string listId, long tagId, CancellationToken ct = default)
     {
-        var list = await _context.Lists.Include(l => l.Tags).FirstAsync(l => l.Id == listId, ct);
+        var list = await _context.Lists.Include(l => l.Tags).FirstOrDefaultAsync(l => l.Id == listId, ct);
+        if (list is null) return;
         var tag = list.Tags.FirstOrDefault(t => t.Id == tagId);
         if (tag is not null)
         {

src/ClaudeDo.Data/Repositories/TaskRepository.cs

@@ -104,7 +104,8 @@ public sealed class TaskRepository
 
     public async Task AddTagAsync(string taskId, long tagId, CancellationToken ct = default)
     {
-        var task = await _context.Tasks.Include(t => t.Tags).FirstAsync(t => t.Id == taskId, ct);
+        var task = await _context.Tasks.Include(t => t.Tags).FirstOrDefaultAsync(t => t.Id == taskId, ct);
+        if (task is null) return;
         var tag = await _context.Tags.FindAsync([tagId], ct);
         if (tag is not null && !task.Tags.Any(t => t.Id == tagId))
         {
@@ -115,7 +116,8 @@ public sealed class TaskRepository
 
     public async Task RemoveTagAsync(string taskId, long tagId, CancellationToken ct = default)
     {
-        var task = await _context.Tasks.Include(t => t.Tags).FirstAsync(t => t.Id == taskId, ct);
+        var task = await _context.Tasks.Include(t => t.Tags).FirstOrDefaultAsync(t => t.Id == taskId, ct);
+        if (task is null) return;
         var tag = task.Tags.FirstOrDefault(t => t.Id == tagId);
         if (tag is not null)
         {

src/ClaudeDo.Installer/Core/InstallContext.cs

@@ -22,7 +22,7 @@ public sealed class InstallContext
     public int SignalRPort { get; set; } = 47_821;
     public int QueueBackstopIntervalMs { get; set; } = 30_000;
     public string ClaudeBin { get; set; } = "claude";
-    public string ServiceAccount { get; set; } = "LocalSystem";
+    public string ServiceAccount { get; set; } = "CurrentUser";
     public bool AutoStart { get; set; } = true;
     public int RestartDelayMs { get; set; } = 5000;
 

src/ClaudeDo.Installer/Steps/WriteConfigStep.cs

@@ -1,3 +1,4 @@
+using ClaudeDo.Data;
 using ClaudeDo.Installer.Core;
 
 namespace ClaudeDo.Installer.Steps;
@@ -10,13 +11,15 @@ public sealed class WriteConfigStep : IInstallStep
     {
         try
         {
+            // Expand ~ to the installing user's absolute path so the worker
+            // service always finds the correct DB regardless of service account.
             var workerCfg = new InstallerWorkerConfig
             {
-                DbPath = ctx.DbPath,
+                DbPath = Paths.Expand(ctx.DbPath),
-                SandboxRoot = ctx.SandboxRoot,
+                SandboxRoot = Paths.Expand(ctx.SandboxRoot),
-                LogRoot = ctx.LogRoot,
+                LogRoot = Paths.Expand(ctx.LogRoot),
                 WorktreeRootStrategy = ctx.WorktreeRootStrategy,
-                CentralWorktreeRoot = ctx.CentralWorktreeRoot,
+                CentralWorktreeRoot = Paths.Expand(ctx.CentralWorktreeRoot),
                 QueueBackstopIntervalMs = ctx.QueueBackstopIntervalMs,
                 SignalRPort = ctx.SignalRPort,
                 ClaudeBin = ctx.ClaudeBin,

src/ClaudeDo.Ui/Services/WorkerClient.cs

@@ -2,6 +2,7 @@ using System.Collections.ObjectModel;
 using Avalonia.Threading;
 using ClaudeDo.Data.Models;
 using CommunityToolkit.Mvvm.ComponentModel;
+using Microsoft.AspNetCore.SignalR;
 using Microsoft.AspNetCore.SignalR.Client;
 
 namespace ClaudeDo.Ui.Services;
@@ -208,9 +209,13 @@ public partial class WorkerClient : ObservableObject, IAsyncDisposable
                     ActiveTasks.Add(new ActiveTask(a.Slot, a.TaskId, a.StartedAt));
             });
         }
-        catch
+        catch (HubException)
         {
-            // Worker might not support GetActive yet
+            // Expected: worker doesn't support GetActive yet
+        }
+        catch (Exception ex)
+        {
+            System.Diagnostics.Debug.WriteLine($"SeedActiveTasksAsync failed: {ex}");
         }
     }
 

src/ClaudeDo.Ui/ViewModels/MainWindowViewModel.cs

@@ -13,7 +13,7 @@ using Microsoft.EntityFrameworkCore;
 
 namespace ClaudeDo.Ui.ViewModels;
 
-public partial class MainWindowViewModel : ViewModelBase
+public partial class MainWindowViewModel : ViewModelBase, IDisposable
 {
     private readonly IDbContextFactory<ClaudeDoDbContext> _dbFactory;
     private readonly WorkerClient _worker;
@@ -27,6 +27,8 @@ public partial class MainWindowViewModel : ViewModelBase
     public TaskDetailViewModel TaskDetail { get; }
     public StatusBarViewModel StatusBar { get; }
 
+    private readonly Action<string> _onTaskChanged;
+
     public MainWindowViewModel(
         IDbContextFactory<ClaudeDoDbContext> dbFactory,
         WorkerClient worker,
@@ -42,8 +44,15 @@ public partial class MainWindowViewModel : ViewModelBase
         TaskDetail = taskDetail;
         StatusBar = statusBar;
 
+        _onTaskChanged = taskId => _ = TaskList.RefreshSingleAsync(taskId);
         TaskList.SelectedTaskChanged += OnSelectedTaskChanged;
-        TaskDetail.TaskChanged += taskId => _ = TaskList.RefreshSingleAsync(taskId);
+        TaskDetail.TaskChanged += _onTaskChanged;
+    }
+
+    public void Dispose()
+    {
+        TaskList.SelectedTaskChanged -= OnSelectedTaskChanged;
+        TaskDetail.TaskChanged -= _onTaskChanged;
     }
 
     public async Task InitializeAsync()
@@ -61,7 +70,11 @@ public partial class MainWindowViewModel : ViewModelBase
             StatusBar.ShowMessage($"Error loading lists: {ex.Message}");
         }
 
-        _ = _worker.StartAsync();
+        _ = _worker.StartAsync().ContinueWith(t =>
+        {
+            if (t.IsFaulted)
+                System.Diagnostics.Debug.WriteLine($"Worker connection failed: {t.Exception?.Message}");
+        }, TaskScheduler.Default);
     }
 
     partial void OnSelectedListChanged(ListItemViewModel? value)
@@ -154,23 +167,46 @@ public partial class MainWindowViewModel : ViewModelBase
         }
     }
 
+    [ObservableProperty] private bool _isDeleteConfirmVisible;
+    private ListItemViewModel? _pendingDeleteList;
+
     [RelayCommand]
-    private async Task DeleteList()
+    private void DeleteList()
     {
         if (SelectedList is null) return;
-        // TODO: confirmation dialog
+        _pendingDeleteList = SelectedList;
+        IsDeleteConfirmVisible = true;
+    }
+
+    [RelayCommand]
+    private async Task ConfirmDeleteList()
+    {
+        IsDeleteConfirmVisible = false;
+        if (_pendingDeleteList is null) return;
         try
         {
             using var context = _dbFactory.CreateDbContext();
             var listRepo = new ListRepository(context);
-            await listRepo.DeleteAsync(SelectedList.Id);
+            await listRepo.DeleteAsync(_pendingDeleteList.Id);
-            Lists.Remove(SelectedList);
+            Lists.Remove(_pendingDeleteList);
+            if (SelectedList == _pendingDeleteList)
                 SelectedList = null;
         }
         catch (Exception ex)
         {
             StatusBar.ShowMessage($"Error deleting list: {ex.Message}");
         }
+        finally
+        {
+            _pendingDeleteList = null;
+        }
+    }
+
+    [RelayCommand]
+    private void CancelDeleteList()
+    {
+        IsDeleteConfirmVisible = false;
+        _pendingDeleteList = null;
     }
 
     private static async Task ShowDialogAsync(Window dialog)

src/ClaudeDo.Ui/ViewModels/TaskDetailViewModel.cs

@@ -282,16 +282,18 @@ public partial class TaskDetailViewModel : ViewModelBase
         if (e.PropertyName is not (nameof(SubtaskItemViewModel.Title) or nameof(SubtaskItemViewModel.Completed))) return;
         try
         {
+            if (_taskId is null) return;
             using var context = _dbFactory.CreateDbContext();
+            var orig = await context.Subtasks.AsNoTracking().FirstOrDefaultAsync(s => s.Id == vm.Id);
             var subtaskRepo = new SubtaskRepository(context);
             await subtaskRepo.UpdateAsync(new SubtaskEntity
             {
                 Id = vm.Id,
-                TaskId = _taskId ?? "",
+                TaskId = _taskId,
                 Title = vm.Title,
                 Completed = vm.Completed,
                 OrderNum = Subtasks.IndexOf(vm),
-                CreatedAt = DateTime.UtcNow,
+                CreatedAt = orig?.CreatedAt ?? DateTime.UtcNow,
             });
         }
         catch (Exception ex)
@@ -378,13 +380,15 @@ public partial class TaskDetailViewModel : ViewModelBase
                 UseShellExecute = true,
             });
         }
-        catch { /* best effort */ }
+        catch (Exception ex)
+        {
+            Debug.WriteLine($"Failed to open worktree: {ex.Message}");
+        }
     }
 
     [RelayCommand]
     private void ShowDiff()
     {
-        // TODO: open a proper diff viewer; for now open git diff in a console
         if (WorktreePath is null) return;
         try
         {
@@ -395,7 +399,10 @@ public partial class TaskDetailViewModel : ViewModelBase
                 UseShellExecute = true,
             });
         }
-        catch { /* best effort */ }
+        catch (Exception ex)
+        {
+            Debug.WriteLine($"Failed to show diff: {ex.Message}");
+        }
     }
 
     [RelayCommand]

src/ClaudeDo.Ui/ViewModels/TaskEditorViewModel.cs

@@ -215,7 +215,10 @@ public partial class TaskEditorViewModel : ViewModelBase
             {
                 if (vm.Id == "") continue;
                 if (vm.Title != vm.OriginalTitle || vm.Completed != vm.OriginalCompleted)
-                    await subtaskRepo.UpdateAsync(new SubtaskEntity { Id = vm.Id, TaskId = taskId, Title = vm.Title, Completed = vm.Completed, OrderNum = idx, CreatedAt = DateTime.UtcNow });
+                {
+                    var origSub = existing.FirstOrDefault(e => e.Id == vm.Id);
+                    await subtaskRepo.UpdateAsync(new SubtaskEntity { Id = vm.Id, TaskId = taskId, Title = vm.Title, Completed = vm.Completed, OrderNum = idx, CreatedAt = origSub?.CreatedAt ?? DateTime.UtcNow });
+                }
                 else
                 {
                     // update order_num if position changed

src/ClaudeDo.Ui/ViewModels/TaskItemViewModel.cs

@@ -1,7 +1,11 @@
+using System.Collections.ObjectModel;
 using Avalonia.Media;
+using ClaudeDo.Data;
 using ClaudeDo.Data.Models;
+using ClaudeDo.Data.Repositories;
 using CommunityToolkit.Mvvm.ComponentModel;
 using CommunityToolkit.Mvvm.Input;
+using Microsoft.EntityFrameworkCore;
 using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
 
 namespace ClaudeDo.Ui.ViewModels;
@@ -15,6 +19,11 @@ public partial class TaskItemViewModel : ViewModelBase
     [ObservableProperty] private string? _description;
     [ObservableProperty] private TaskStatus _status;
     [ObservableProperty] private bool _isStarting;
+    [ObservableProperty] private bool _isExpanded;
+    [ObservableProperty] private bool _hasSubtasks;
+    [ObservableProperty] private int _subtaskCount;
+
+    public ObservableCollection<SubtaskItemViewModel> Subtasks { get; } = new();
 
     public string Id { get; }
     public string ListId { get; }
@@ -23,9 +32,13 @@ public partial class TaskItemViewModel : ViewModelBase
     private readonly Func<string, Task>? _runNow;
     private readonly Func<bool> _canRunNow;
     private readonly Func<string, Task>? _toggleDone;
+    private readonly IDbContextFactory<ClaudeDoDbContext> _dbFactory;
+    private bool _subtasksLoaded;
 
     public TaskItemViewModel(TaskEntity entity, IReadOnlyList<TagEntity> tags,
-        Func<string, Task>? runNow, Func<bool> canRunNow, Func<string, Task>? toggleDone = null)
+        Func<string, Task>? runNow, Func<bool> canRunNow,
+        IDbContextFactory<ClaudeDoDbContext> dbFactory, int subtaskCount,
+        Func<string, Task>? toggleDone = null)
     {
         Entity = entity;
         Id = entity.Id;
@@ -39,6 +52,9 @@ public partial class TaskItemViewModel : ViewModelBase
         _runNow = runNow;
         _canRunNow = canRunNow;
         _toggleDone = toggleDone;
+        _dbFactory = dbFactory;
+        _subtaskCount = subtaskCount;
+        _hasSubtasks = subtaskCount > 0;
     }
 
     public bool IsDone => Status == TaskStatus.Done;
@@ -104,4 +120,55 @@ public partial class TaskItemViewModel : ViewModelBase
         if (_toggleDone is not null)
             await _toggleDone(Id);
     }
+
+    [RelayCommand]
+    private async Task ToggleExpanded()
+    {
+        IsExpanded = !IsExpanded;
+        if (IsExpanded && !_subtasksLoaded)
+            await LoadSubtasksAsync();
+    }
+
+    private async Task LoadSubtasksAsync()
+    {
+        using var context = _dbFactory.CreateDbContext();
+        var repo = new SubtaskRepository(context);
+        var entities = await repo.GetByTaskIdAsync(Id);
+        Subtasks.Clear();
+        foreach (var e in entities)
+            Subtasks.Add(SubtaskItemViewModel.From(e));
+        _subtasksLoaded = true;
+    }
+
+    [RelayCommand]
+    private async Task ToggleSubtaskDone(string subtaskId)
+    {
+        var vm = Subtasks.FirstOrDefault(s => s.Id == subtaskId);
+        if (vm is null) return;
+        vm.Completed = !vm.Completed;
+
+        using var context = _dbFactory.CreateDbContext();
+        var entity = await context.Subtasks.FindAsync(subtaskId);
+        if (entity is not null)
+        {
+            entity.Completed = vm.Completed;
+            await context.SaveChangesAsync();
+        }
+    }
+
+    public async Task RefreshSubtasksAsync(int newCount)
+    {
+        SubtaskCount = newCount;
+        HasSubtasks = newCount > 0;
+        if (!HasSubtasks)
+        {
+            IsExpanded = false;
+            Subtasks.Clear();
+            _subtasksLoaded = false;
+        }
+        else if (_subtasksLoaded || IsExpanded)
+        {
+            await LoadSubtasksAsync();
+        }
+    }
 }

src/ClaudeDo.Ui/ViewModels/TaskListViewModel.cs

@@ -91,10 +91,17 @@ public partial class TaskListViewModel : ViewModelBase
             using var context = _dbFactory.CreateDbContext();
             var taskRepo = new TaskRepository(context);
             var entities = await taskRepo.GetByListIdAsync(listId);
+            var taskIds = entities.Select(e => e.Id).ToList();
+            var subtaskCounts = await context.Subtasks
+                .Where(s => taskIds.Contains(s.TaskId))
+                .GroupBy(s => s.TaskId)
+                .ToDictionaryAsync(g => g.Key, g => g.Count());
             foreach (var e in entities)
             {
                 var tags = await taskRepo.GetEffectiveTagsAsync(e.Id);
-                Tasks.Add(new TaskItemViewModel(e, tags, RunNowAsync, () => _worker.IsConnected, ToggleDoneAsync));
+                subtaskCounts.TryGetValue(e.Id, out var count);
+                Tasks.Add(new TaskItemViewModel(e, tags, RunNowAsync, () => _worker.IsConnected,
+                    _dbFactory, count, ToggleDoneAsync));
             }
         }
         catch (Exception ex)
@@ -135,7 +142,8 @@ public partial class TaskListViewModel : ViewModelBase
             var taskRepo = new TaskRepository(context);
             await taskRepo.AddAsync(entity);
             var tags = await taskRepo.GetEffectiveTagsAsync(entity.Id);
-            var vm = new TaskItemViewModel(entity, tags, RunNowAsync, () => _worker.IsConnected, ToggleDoneAsync);
+            var vm = new TaskItemViewModel(entity, tags, RunNowAsync, () => _worker.IsConnected,
+                _dbFactory, 0, ToggleDoneAsync);
             Tasks.Add(vm);
             SelectedTask = vm;
             InlineAddTitle = "";
@@ -183,7 +191,8 @@ public partial class TaskListViewModel : ViewModelBase
             }
 
             var tags = await taskRepo.GetEffectiveTagsAsync(saved.Id);
-            Tasks.Add(new TaskItemViewModel(saved, tags, RunNowAsync, () => _worker.IsConnected, ToggleDoneAsync));
+            Tasks.Add(new TaskItemViewModel(saved, tags, RunNowAsync, () => _worker.IsConnected,
+                _dbFactory, 0, ToggleDoneAsync));
 
             // Auto wake-queue if agent+queued
             if (saved.Status == TaskStatus.Queued &&
@@ -282,7 +291,11 @@ public partial class TaskListViewModel : ViewModelBase
         }
         var tags = await taskRepo.GetEffectiveTagsAsync(taskId);
         if (existing is not null)
+        {
             existing.Refresh(entity, tags);
+            var subtaskCount = await context.Subtasks.CountAsync(s => s.TaskId == taskId);
+            await existing.RefreshSubtasksAsync(subtaskCount);
+        }
     }
 
     private async Task RunNowAsync(string taskId)

src/ClaudeDo.Ui/Views/TaskListView.axaml

@@ -31,9 +31,11 @@
                  KeyDown="OnTaskListKeyDown">
             <ListBox.ItemTemplate>
                 <DataTemplate x:DataType="vm:TaskItemViewModel">
-                    <Grid ColumnDefinitions="Auto,*" Margin="4,4"
+                    <Grid RowDefinitions="Auto,Auto"
                           Background="Transparent"
-                          Opacity="{Binding RowOpacity}"
+                          Opacity="{Binding RowOpacity}">
+                        <!-- Row 0: Task row -->
+                        <Grid Grid.Row="0" ColumnDefinitions="20,Auto,*" Margin="4,4"
                               DoubleTapped="OnTaskItemDoubleTapped"
                               PointerPressed="OnTaskItemPointerPressed">
                             <Grid.ContextFlyout>
@@ -48,8 +50,32 @@
                                 </MenuFlyout>
                             </Grid.ContextFlyout>
 
+                            <!-- Expand/collapse chevron -->
+                            <Button Grid.Column="0"
+                                    Command="{Binding ToggleExpandedCommand}"
+                                    IsVisible="{Binding HasSubtasks}"
+                                    Background="Transparent"
+                                    BorderThickness="0"
+                                    Padding="0"
+                                    Width="16" Height="16"
+                                    VerticalAlignment="Center"
+                                    Cursor="Hand">
+                                <Panel>
+                                    <Canvas Width="10" Height="10"
+                                            IsVisible="{Binding !IsExpanded}">
+                                        <Path Stroke="{StaticResource TextDimBrush}" StrokeThickness="1.5"
+                                              Data="M 2,0 L 8,5 L 2,10"/>
+                                    </Canvas>
+                                    <Canvas Width="10" Height="10"
+                                            IsVisible="{Binding IsExpanded}">
+                                        <Path Stroke="{StaticResource TextDimBrush}" StrokeThickness="1.5"
+                                              Data="M 0,2 L 5,8 L 10,2"/>
+                                    </Canvas>
+                                </Panel>
+                            </Button>
+
                             <!-- Circular checkbox -->
-                        <Border Grid.Column="0" Width="22" Height="22"
+                            <Border Grid.Column="1" Width="22" Height="22"
                                     CornerRadius="11"
                                     BorderThickness="2"
                                     BorderBrush="{Binding StatusText, Converter={x:Static conv:CheckboxBorderConverter.Instance}}"
@@ -58,19 +84,16 @@
                                     Cursor="Hand"
                                     PointerPressed="OnCheckboxPressed">
                                 <Panel>
-                                <!-- Checkmark for done -->
                                     <Canvas Width="12" Height="12"
                                             IsVisible="{Binding IsDone}"
                                             HorizontalAlignment="Center" VerticalAlignment="Center">
                                         <Path Stroke="{StaticResource StatusGreenBrush}" StrokeThickness="2"
                                               Data="M 1,6 L 4.5,9.5 L 11,3"/>
                                     </Canvas>
-                                <!-- Running dot -->
                                     <Ellipse Width="8" Height="8"
                                              Fill="{StaticResource StatusOrangeBrush}"
                                              IsVisible="{Binding IsRunning}"
                                              HorizontalAlignment="Center" VerticalAlignment="Center"/>
-                                <!-- Starting dot -->
                                     <Ellipse Width="8" Height="8" Fill="#FFD700"
                                              IsVisible="{Binding IsStarting}"
                                              HorizontalAlignment="Center" VerticalAlignment="Center"/>
@@ -78,7 +101,7 @@
                             </Border>
 
                             <!-- Task content -->
-                        <StackPanel Grid.Column="1" VerticalAlignment="Center">
+                            <StackPanel Grid.Column="2" VerticalAlignment="Center">
                                 <TextBlock Text="{Binding Title}" FontWeight="Medium"
                                            Foreground="{Binding TitleForeground}"
                                            TextDecorations="{Binding TitleDecorations}"
@@ -98,6 +121,39 @@
                                            IsVisible="{Binding TagsText, Converter={x:Static StringConverters.IsNullOrEmpty}}"/>
                             </StackPanel>
                         </Grid>
+
+                        <!-- Row 1: Subtask list (visible when expanded) -->
+                        <ItemsControl Grid.Row="1"
+                                      ItemsSource="{Binding Subtasks}"
+                                      IsVisible="{Binding IsExpanded}"
+                                      Margin="40,0,0,4">
+                            <ItemsControl.ItemTemplate>
+                                <DataTemplate x:DataType="vm:SubtaskItemViewModel">
+                                    <Grid ColumnDefinitions="Auto,*" Margin="0,2"
+                                          PointerPressed="OnSubtaskPointerPressed">
+                                        <Grid.ContextFlyout>
+                                            <MenuFlyout>
+                                                <MenuItem Header="Edit Task"
+                                                          Command="{Binding #Root.((vm:TaskListViewModel)DataContext).EditTaskCommand}"/>
+                                            </MenuFlyout>
+                                        </Grid.ContextFlyout>
+                                        <CheckBox Grid.Column="0"
+                                                  IsChecked="{Binding Completed, Mode=OneWay}"
+                                                  VerticalAlignment="Center"
+                                                  Margin="0,0,6,0"
+                                                  MinWidth="0"
+                                                  Click="OnSubtaskCheckboxClick"/>
+                                        <TextBlock Grid.Column="1"
+                                                   Text="{Binding Title}"
+                                                   FontSize="12"
+                                                   Foreground="{StaticResource TextDimBrush}"
+                                                   VerticalAlignment="Center"
+                                                   TextTrimming="CharacterEllipsis"/>
+                                    </Grid>
+                                </DataTemplate>
+                            </ItemsControl.ItemTemplate>
+                        </ItemsControl>
+                    </Grid>
                 </DataTemplate>
             </ListBox.ItemTemplate>
         </ListBox>

src/ClaudeDo.Ui/Views/TaskListView.axaml.cs

@@ -1,3 +1,4 @@
+using System.Collections.ObjectModel;
 using Avalonia.Controls;
 using Avalonia.Input;
 using Avalonia.Interactivity;
@@ -97,6 +98,29 @@ public partial class TaskListView : UserControl
         }
     }
 
+    private void OnSubtaskPointerPressed(object? sender, PointerPressedEventArgs e)
+    {
+        if (e.GetCurrentPoint(null).Properties.IsRightButtonPressed
+            && sender is Control { DataContext: SubtaskItemViewModel subtask }
+            && DataContext is TaskListViewModel vm)
+        {
+            var parent = vm.Tasks.FirstOrDefault(t => t.Subtasks.Contains(subtask));
+            if (parent is not null)
+                vm.SelectedTask = parent;
+        }
+    }
+
+    private async void OnSubtaskCheckboxClick(object? sender, RoutedEventArgs e)
+    {
+        if (sender is CheckBox { DataContext: SubtaskItemViewModel subtask }
+            && DataContext is TaskListViewModel vm)
+        {
+            var parent = vm.Tasks.FirstOrDefault(t => t.Subtasks.Contains(subtask));
+            if (parent is not null)
+                await parent.ToggleSubtaskDoneCommand.ExecuteAsync(subtask.Id);
+        }
+    }
+
     public void FocusInlineAdd()
     {
         this.FindControl<TextBox>("InlineAddBox")?.Focus();

src/ClaudeDo.Worker/Hub/WorkerHub.cs

@@ -5,6 +5,8 @@ using Microsoft.AspNetCore.SignalR;
 
 namespace ClaudeDo.Worker.Hub;
 
+public record ActiveTaskDto(string Slot, string TaskId, DateTime StartedAt);
+
 public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
 {
     private static readonly string Version =
@@ -12,19 +14,21 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
 
     private readonly QueueService _queue;
     private readonly AgentFileService _agentService;
+    private readonly HubBroadcaster _broadcaster;
 
-    public WorkerHub(QueueService queue, AgentFileService agentService)
+    public WorkerHub(QueueService queue, AgentFileService agentService, HubBroadcaster broadcaster)
     {
         _queue = queue;
         _agentService = agentService;
+        _broadcaster = broadcaster;
     }
 
     public string Ping() => $"pong v{Version}";
 
-    public IReadOnlyList<object> GetActive()
+    public IReadOnlyList<ActiveTaskDto> GetActive()
     {
         return _queue.GetActive()
-            .Select(a => (object)new { slot = a.slot, taskId = a.taskId, startedAt = a.startedAt })
+            .Select(a => new ActiveTaskDto(a.slot, a.taskId, a.startedAt))
             .ToList();
     }
 
@@ -33,6 +37,7 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         try
         {
             await _queue.RunNow(taskId);
+            await _broadcaster.RunCreated(taskId, 1, false);
         }
         catch (InvalidOperationException)
         {

src/ClaudeDo.Worker/Services/QueueService.cs

@@ -58,11 +58,13 @@ public sealed class QueueService : BackgroundService
 
     public async Task RunNow(string taskId)
     {
-        using var context = _dbFactory.CreateDbContext();
+        using (var context = _dbFactory.CreateDbContext())
+        {
             var taskRepo = new TaskRepository(context);
-        var task = await taskRepo.GetByIdAsync(taskId);
+            var exists = await taskRepo.GetByIdAsync(taskId);
-        if (task is null)
+            if (exists is null)
                 throw new KeyNotFoundException($"Task '{taskId}' not found.");
+        }
 
         lock (_lock)
         {
@@ -72,8 +74,10 @@ public sealed class QueueService : BackgroundService
             var cts = new CancellationTokenSource();
             _overrideSlot = new QueueSlotState { TaskId = taskId, StartedAt = DateTime.UtcNow, Cts = cts };
 
-            _ = RunInSlotAsync(task, "override", cts.Token).ContinueWith(_ =>
+            _ = RunInSlotAsync(taskId, "override", cts.Token).ContinueWith(t =>
             {
+                if (t.IsFaulted)
+                    _logger.LogError(t.Exception, "RunInSlotAsync failed for task {TaskId}", taskId);
                 lock (_lock) { _overrideSlot = null; }
                 cts.Dispose();
             }, TaskScheduler.Default);
@@ -98,8 +102,10 @@ public sealed class QueueService : BackgroundService
             var cts = new CancellationTokenSource();
             _overrideSlot = new QueueSlotState { TaskId = taskId, StartedAt = DateTime.UtcNow, Cts = cts };
 
-            _ = RunContinueInSlotAsync(taskId, followUpPrompt, cts.Token).ContinueWith(_ =>
+            _ = RunContinueInSlotAsync(taskId, followUpPrompt, cts.Token).ContinueWith(t =>
             {
+                if (t.IsFaulted)
+                    _logger.LogError(t.Exception, "RunContinueInSlotAsync failed for task {TaskId}", taskId);
                 lock (_lock) { _overrideSlot = null; }
                 cts.Dispose();
             }, TaskScheduler.Default);
@@ -165,8 +171,10 @@ public sealed class QueueService : BackgroundService
                     var cts = CancellationTokenSource.CreateLinkedTokenSource(stoppingToken);
                     _queueSlot = new QueueSlotState { TaskId = task.Id, StartedAt = DateTime.UtcNow, Cts = cts };
 
-                    _ = RunInSlotAsync(task, "queue", cts.Token).ContinueWith(_ =>
+                    _ = RunInSlotAsync(task.Id, "queue", cts.Token).ContinueWith(t =>
                     {
+                        if (t.IsFaulted)
+                            _logger.LogError(t.Exception, "RunInSlotAsync failed for task {TaskId} in queue slot", task.Id);
                         lock (_lock) { _queueSlot = null; }
                         cts.Dispose();
                         WakeQueue(); // Check for next task immediately.
@@ -186,16 +194,25 @@ public sealed class QueueService : BackgroundService
         _logger.LogInformation("QueueService stopping");
     }
 
-    private async Task RunInSlotAsync(TaskEntity task, string slot, CancellationToken ct)
+    private async Task RunInSlotAsync(string taskId, string slot, CancellationToken ct)
     {
         try
         {
-            _logger.LogInformation("Starting task {TaskId} in {Slot} slot", task.Id, slot);
+            _logger.LogInformation("Starting task {TaskId} in {Slot} slot", taskId, slot);
+
+            TaskEntity task;
+            using (var context = _dbFactory.CreateDbContext())
+            {
+                var taskRepo = new TaskRepository(context);
+                task = await taskRepo.GetByIdAsync(taskId, ct)
+                    ?? throw new KeyNotFoundException($"Task '{taskId}' not found.");
+            }
+
             await _runner.RunAsync(task, slot, ct);
         }
         catch (Exception ex)
         {
-            _logger.LogError(ex, "Slot runner error for task {TaskId}", task.Id);
+            _logger.LogError(ex, "Slot runner error for task {TaskId}", taskId);
         }
     }