From 92ce7a4a77b4aa6896c721eb8d402f0144128663 Mon Sep 17 00:00:00 2001
From: Mika Kuns <mika.kuns@fb-tuning.de>
Date: Wed, 29 Jul 2026 15:10:59 +0200
Subject: [PATCH] feat(ui): move a task to another list via drag & drop

Dragging a task row onto a user list in the Lists island now reassigns it
to that list. The task drag holds the pointer capture, so the release is
resolved geometrically (new case between the Mission Control and reorder
cases) instead of going through the Lists island's own DragDrop path,
which never sees a DragEventArgs during a task drag.

TaskRepository.MoveToListAsync reassigns the task plus every descendant
(a child must never sit in a different list than its parent) and appends
the task at the end of the target list. Guards: running tasks and tasks
holding an Active/Kept worktree are rejected to the footer error strip;
a move that changes repo asks for confirmation naming both repos.

The source repo is read from the task's own list rather than the island's
current list, which is a smart/virtual list with no working dir of its own
whenever one of those is shown.
---
 .../Repositories/TaskRepository.cs            |  54 +++
 src/ClaudeDo.Localization/locales/de.json     |   2 +-
 src/ClaudeDo.Localization/locales/en.json     |   2 +-
 src/ClaudeDo.Ui/Design/IslandStyles.axaml     |   9 +
 .../Islands/ListNavItemViewModel.cs           |   3 +
 .../Islands/TasksIslandViewModel.cs           |  75 ++++
 .../ViewModels/IslandsShellViewModel.cs       |   1 +
 .../Views/Islands/ListsIslandView.axaml       |   1 +
 .../Views/Islands/TasksIslandView.axaml.cs    |  58 ++-
 tests/ClaudeDo.Data.Tests/MoveToListTests.cs  | 143 ++++++++
 .../ViewModels/TasksIslandMoveToListTests.cs  | 346 ++++++++++++++++++
 11 files changed, 690 insertions(+), 4 deletions(-)
 create mode 100644 tests/ClaudeDo.Data.Tests/MoveToListTests.cs
 create mode 100644 tests/ClaudeDo.Ui.Tests/ViewModels/TasksIslandMoveToListTests.cs

diff --git a/src/ClaudeDo.Data/Repositories/TaskRepository.cs b/src/ClaudeDo.Data/Repositories/TaskRepository.cs
index e68e57f4..b3e48255 100644
--- a/src/ClaudeDo.Data/Repositories/TaskRepository.cs
+++ b/src/ClaudeDo.Data/Repositories/TaskRepository.cs
@@ -84,6 +84,60 @@ public sealed class TaskRepository
     public Task<List<TaskEntity>> GetByListAsync(string listId, CancellationToken ct = default)
         => GetByListIdAsync(listId, ct);
 
+    /// <summary>
+    /// Returns the ids of every descendant of <paramref name="taskId"/> (children, grandchildren, ...),
+    /// walking the ParentTaskId chain breadth-first. Does not include the task itself.
+    /// </summary>
+    public async Task<List<string>> GetDescendantIdsAsync(string taskId, CancellationToken ct = default)
+    {
+        var result = new List<string>();
+        // Guards against a corrupt parent chain (a self-parent or a cycle would loop forever).
+        var seen = new HashSet<string>(StringComparer.Ordinal) { taskId };
+        var frontier = new List<string> { taskId };
+        while (frontier.Count > 0)
+        {
+            var children = await _context.Tasks.AsNoTracking()
+                .Where(t => t.ParentTaskId != null && frontier.Contains(t.ParentTaskId))
+                .Select(t => t.Id)
+                .ToListAsync(ct);
+            var fresh = children.Where(seen.Add).ToList();
+            if (fresh.Count == 0) break;
+            result.AddRange(fresh);
+            frontier = fresh;
+        }
+        return result;
+    }
+
+    /// <summary>
+    /// Moves a task (and every descendant, so a child never ends up in a different list than its
+    /// parent) to <paramref name="targetListId"/>, appending it at the end of the target list's
+    /// order. ListId is init-only, so the move goes through ExecuteUpdate rather than a tracked
+    /// entity mutation.
+    /// </summary>
+    public async Task MoveToListAsync(string taskId, string targetListId, CancellationToken ct = default)
+    {
+        var exists = await _context.Tasks.AsNoTracking().AnyAsync(t => t.Id == taskId, ct);
+        if (!exists)
+            throw new InvalidOperationException($"Task {taskId} not found.");
+
+        var descendantIds = await GetDescendantIdsAsync(taskId, ct);
+        var movedIds = new List<string> { taskId };
+        movedIds.AddRange(descendantIds);
+
+        var maxSort = await _context.Tasks
+            .Where(t => t.ListId == targetListId)
+            .Select(t => (int?)t.SortOrder)
+            .MaxAsync(ct);
+
+        await _context.Tasks
+            .Where(t => movedIds.Contains(t.Id))
+            .ExecuteUpdateAsync(s => s.SetProperty(t => t.ListId, targetListId), ct);
+
+        await _context.Tasks
+            .Where(t => t.Id == taskId)
+            .ExecuteUpdateAsync(s => s.SetProperty(t => t.SortOrder, (maxSort ?? -1) + 1), ct);
+    }
+
     public async Task<List<TaskEntity>> GetByCreatorAsync(string createdBy, CancellationToken ct = default)
     {
         return await _context.Tasks
diff --git a/src/ClaudeDo.Localization/locales/de.json b/src/ClaudeDo.Localization/locales/de.json
index d63a6441..d6b425f9 100644
--- a/src/ClaudeDo.Localization/locales/de.json
+++ b/src/ClaudeDo.Localization/locales/de.json
@@ -542,7 +542,7 @@
     "taskStatus": { "idle": "Leerlauf", "queued": "In Warteschlange", "running": "Läuft", "waitingForReview": "Wartet auf Prüfung", "waitingForChildren": "Wartet auf Teilaufgaben", "done": "Fertig", "failed": "Fehlgeschlagen", "cancelled": "Abgebrochen", "parked": "Geparkt", "interactive": "Interaktiv" },
     "planningBadge": { "active": "PLANUNG", "finalized": "GEPLANT" },
     "taskRow": { "createdPrefix": "Erstellt {0}", "stepsText": "{0}/{1} Schritte" },
-    "tasksIsland": { "completedHeader": "ABGESCHLOSSEN", "completedHeaderCount": "ABGESCHLOSSEN · {0}", "planningOpenFailed": "Planungssitzung konnte nicht geöffnet werden: {0}", "planningResumeFailed": "Planungssitzung konnte nicht fortgesetzt werden: {0}", "pickUpInTerminalFailed": "Im Terminal fortsetzen fehlgeschlagen: {0}", "approveFailed": "Genehmigen & Mergen fehlgeschlagen: {0}" },
+    "tasksIsland": { "completedHeader": "ABGESCHLOSSEN", "completedHeaderCount": "ABGESCHLOSSEN · {0}", "planningOpenFailed": "Planungssitzung konnte nicht geöffnet werden: {0}", "planningResumeFailed": "Planungssitzung konnte nicht fortgesetzt werden: {0}", "pickUpInTerminalFailed": "Im Terminal fortsetzen fehlgeschlagen: {0}", "approveFailed": "Genehmigen & Mergen fehlgeschlagen: {0}", "moveRunningRejected": "Ein laufender Task kann nicht in eine andere Liste verschoben werden.", "moveWorktreeRejected": "Verschieben nicht möglich — dieser Task hat einen aktiven Worktree, der auf sein aktuelles Repo zeigt.", "moveRepoConfirm": "Unterschiedliche Repos — {0} → {1}. Task trotzdem verschieben?", "moveConfirmUnavailable": "Verschieben nicht möglich — der Bestätigungsdialog ist nicht verfügbar." },
     "diff": { "loadFailed": "Diff konnte nicht geladen werden: {0}", "noChanges": "Keine Änderungen anzuzeigen.", "unavailable": "Diff nicht mehr verfügbar — Commit-Bereich unvollständig." },
     "planningDiff": { "hubError": "Kombinierte Vorschau konnte nicht erstellt werden (Hub-Fehler).", "conflict": "Kombinierte Vorschau nicht möglich: Teilaufgabe {0} steht im Konflikt mit einer früheren Teilaufgabe ({1} Dateien).", "buildFailed": "Kombinierte Vorschau konnte nicht erstellt werden: {0}" },
     "merge": { "commitMessage": "Merge-Aufgabe: {0}", "workerOfflineBranches": "Worker offline — Branches können nicht aufgelistet werden.", "loadBranchesFailed": "Branches konnten nicht geladen werden: {0}", "merged": "Zusammengeführt.", "conflict": "Merge-Konflikt — Ziel-Branch wiederhergestellt. Manuell oder über Fortsetzen lösen, dann erneut versuchen.", "blocked": "Blockiert: {0}", "unknownStatus": "Unbekannter Status: {0}", "mergeFailed": "Merge fehlgeschlagen: {0}" },
diff --git a/src/ClaudeDo.Localization/locales/en.json b/src/ClaudeDo.Localization/locales/en.json
index 3f86548b..86db406c 100644
--- a/src/ClaudeDo.Localization/locales/en.json
+++ b/src/ClaudeDo.Localization/locales/en.json
@@ -542,7 +542,7 @@
     "taskStatus": { "idle": "Idle", "queued": "Queued", "running": "Running", "waitingForReview": "Waiting for Review", "waitingForChildren": "Waiting for Subtasks", "done": "Done", "failed": "Failed", "cancelled": "Cancelled", "parked": "Parked", "interactive": "Interactive" },
     "planningBadge": { "active": "PLANNING", "finalized": "PLANNED" },
     "taskRow": { "createdPrefix": "Created {0}", "stepsText": "{0}/{1} steps" },
-    "tasksIsland": { "completedHeader": "COMPLETED", "completedHeaderCount": "COMPLETED · {0}", "planningOpenFailed": "Couldn't open planning session: {0}", "planningResumeFailed": "Couldn't resume planning session: {0}", "pickUpInTerminalFailed": "Pick up in terminal failed: {0}", "approveFailed": "Approve & merge failed: {0}" },
+    "tasksIsland": { "completedHeader": "COMPLETED", "completedHeaderCount": "COMPLETED · {0}", "planningOpenFailed": "Couldn't open planning session: {0}", "planningResumeFailed": "Couldn't resume planning session: {0}", "pickUpInTerminalFailed": "Pick up in terminal failed: {0}", "approveFailed": "Approve & merge failed: {0}", "moveRunningRejected": "Can't move a running task to another list.", "moveWorktreeRejected": "Can't move — this task has an active worktree pointing at its current repo.", "moveRepoConfirm": "Different repos — {0} → {1}. Move the task anyway?", "moveConfirmUnavailable": "Can't move — the confirmation dialog isn't available." },
     "diff": { "loadFailed": "Failed to load diff: {0}", "noChanges": "No changes to show.", "unavailable": "Diff no longer available — commit range incomplete." },
     "planningDiff": { "hubError": "Could not build combined preview (hub error).", "conflict": "Cannot build combined preview: subtask {0} conflicts with an earlier subtask ({1} files).", "buildFailed": "Could not build combined preview: {0}" },
     "merge": { "commitMessage": "Merge task: {0}", "workerOfflineBranches": "Worker offline — cannot list branches.", "loadBranchesFailed": "Failed to load branches: {0}", "merged": "Merged.", "conflict": "Merge conflict — target branch restored. Resolve manually or via Continue, then retry.", "blocked": "Blocked: {0}", "unknownStatus": "Unknown status: {0}", "mergeFailed": "Merge failed: {0}" },
diff --git a/src/ClaudeDo.Ui/Design/IslandStyles.axaml b/src/ClaudeDo.Ui/Design/IslandStyles.axaml
index 577515c4..da7c8242 100644
--- a/src/ClaudeDo.Ui/Design/IslandStyles.axaml
+++ b/src/ClaudeDo.Ui/Design/IslandStyles.axaml
@@ -693,6 +693,10 @@
     <Setter Property="CornerRadius" Value="8" />
     <Setter Property="Cursor"       Value="Hand" />
     <Setter Property="Background"   Value="Transparent" />
+    <!-- Reserved so the task-drop highlight below only swaps the brush — a thickness that changes
+         on hover would nudge the row's content while dragging over it. -->
+    <Setter Property="BorderThickness" Value="1.5" />
+    <Setter Property="BorderBrush"     Value="Transparent" />
   </Style>
   <Style Selector="Border.list-item:pointerover">
     <Setter Property="Background" Value="{StaticResource Surface2Brush}" />
@@ -700,6 +704,11 @@
   <Style Selector="Border.list-item.active">
     <Setter Property="Background" Value="{StaticResource AccentSoftBrush}" />
   </Style>
+  <!-- Highlighted while a dragged task hovers over this row as a move target. -->
+  <Style Selector="Border.list-item.drop-target">
+    <Setter Property="Background"  Value="{StaticResource AccentSoftBrush}" />
+    <Setter Property="BorderBrush" Value="{StaticResource AccentBrush}" />
+  </Style>
   <!-- Active item text / icon colors -->
   <Style Selector="Border.list-item.active TextBlock.list-label">
     <Setter Property="Foreground" Value="{StaticResource TextBrush}" />
diff --git a/src/ClaudeDo.Ui/ViewModels/Islands/ListNavItemViewModel.cs b/src/ClaudeDo.Ui/ViewModels/Islands/ListNavItemViewModel.cs
index 55ddda23..eae38177 100644
--- a/src/ClaudeDo.Ui/ViewModels/Islands/ListNavItemViewModel.cs
+++ b/src/ClaudeDo.Ui/ViewModels/Islands/ListNavItemViewModel.cs
@@ -16,6 +16,9 @@ public sealed partial class ListNavItemViewModel : ViewModelBase
     [ObservableProperty] private bool _isManual;
     [ObservableProperty] private bool _dropHintAbove;
     [ObservableProperty] private bool _dropHintBelow;
+    // Set while a dragged task hovers over this row as a move target — distinct from
+    // DropHintAbove/Below, which mark an insertion point for list reordering.
+    [ObservableProperty] private bool _isTaskDropTarget;
     public string? IconKey { get; init; }
     public string? DotColorKey { get; init; }
 }
diff --git a/src/ClaudeDo.Ui/ViewModels/Islands/TasksIslandViewModel.cs b/src/ClaudeDo.Ui/ViewModels/Islands/TasksIslandViewModel.cs
index 8c23e97a..d8446c82 100644
--- a/src/ClaudeDo.Ui/ViewModels/Islands/TasksIslandViewModel.cs
+++ b/src/ClaudeDo.Ui/ViewModels/Islands/TasksIslandViewModel.cs
@@ -471,6 +471,11 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
     }
 
     public bool CanReorder => _currentList?.Kind == ListKind.User;
+    public string? CurrentListId => _currentList?.Id;
+
+    /// <summary>Set by the shell (mirrors <see cref="ListsIslandViewModel.Dialogs"/>) so a
+    /// cross-repo move can confirm via the shared modal seam.</summary>
+    public IDialogService? Dialogs { get; set; }
 
     public void ClearDropHints()
     {
@@ -573,6 +578,76 @@ public sealed partial class TasksIslandViewModel : ViewModelBase, IDisposable
         return null;
     }
 
+    /// <summary>
+    /// Drag-drop move: reassigns a task (and every descendant) to <paramref name="targetList"/>.
+    /// No-op for anything that isn't a user list the task doesn't already sit in.
+    /// Rejects running tasks and tasks (or descendants) holding an Active/Kept worktree — the
+    /// worktree would keep pointing at the source repo. A move across repos without a worktree
+    /// is allowed but asks for confirmation first.
+    /// </summary>
+    public async Task MoveTaskToListAsync(TaskRowViewModel row, ListNavItemViewModel targetList)
+    {
+        if (targetList.Kind != ListKind.User) return;
+        var targetListId = targetList.Id.StartsWith("user:", StringComparison.Ordinal)
+            ? targetList.Id["user:".Length..]
+            : targetList.Id;
+
+        await using var db = await _dbFactory.CreateDbContextAsync();
+
+        // The row's own list, not _currentList — the task island also shows smart/virtual lists,
+        // whose rows come from many lists and which carry no working dir of their own. Dropping a
+        // task on the list it already sits in is a silent no-op.
+        var sourceListId = await db.Tasks.AsNoTracking()
+            .Where(t => t.Id == row.Id).Select(t => t.ListId).FirstOrDefaultAsync();
+        if (sourceListId is null || sourceListId == targetListId) return;
+
+        if (row.IsRunning)
+        {
+            ErrorReported?.Invoke(Loc.T("vm.tasksIsland.moveRunningRejected"));
+            return;
+        }
+
+        var repo = new TaskRepository(db);
+
+        var descendantIds = await repo.GetDescendantIdsAsync(row.Id);
+        var ownIds = new List<string> { row.Id };
+        ownIds.AddRange(descendantIds);
+        var hasBlockingWorktree = await db.Worktrees.AsNoTracking()
+            .Where(w => ownIds.Contains(w.TaskId)
+                        && (w.State == ClaudeDo.Data.Models.WorktreeState.Active
+                            || w.State == ClaudeDo.Data.Models.WorktreeState.Kept))
+            .AnyAsync();
+        if (hasBlockingWorktree)
+        {
+            ErrorReported?.Invoke(Loc.T("vm.tasksIsland.moveWorktreeRejected"));
+            return;
+        }
+
+        var sourceDir = await db.Lists.AsNoTracking()
+            .Where(l => l.Id == sourceListId).Select(l => l.WorkingDir).FirstOrDefaultAsync();
+        var targetDir = targetList.WorkingDir;
+        var repoChanges = !string.Equals(sourceDir, targetDir, StringComparison.OrdinalIgnoreCase);
+        if (repoChanges)
+        {
+            if (Dialogs is null)
+            {
+                ErrorReported?.Invoke(Loc.T("vm.tasksIsland.moveConfirmUnavailable"));
+                return;
+            }
+            var ok = await Dialogs.ConfirmAsync(Loc.T("vm.tasksIsland.moveRepoConfirm",
+                string.IsNullOrWhiteSpace(sourceDir) ? "—" : sourceDir,
+                string.IsNullOrWhiteSpace(targetDir) ? "—" : targetDir));
+            if (!ok) return;
+        }
+
+        await repo.MoveToListAsync(row.Id, targetListId);
+
+        Items.Remove(row);
+        Regroup();
+        UpdateSubtitle();
+        TasksChanged?.Invoke(this, EventArgs.Empty);
+    }
+
     [RelayCommand]
     private async Task ToggleDoneAsync(TaskRowViewModel row)
     {
diff --git a/src/ClaudeDo.Ui/ViewModels/IslandsShellViewModel.cs b/src/ClaudeDo.Ui/ViewModels/IslandsShellViewModel.cs
index eb0ec9de..43ad8518 100644
--- a/src/ClaudeDo.Ui/ViewModels/IslandsShellViewModel.cs
+++ b/src/ClaudeDo.Ui/ViewModels/IslandsShellViewModel.cs
@@ -56,6 +56,7 @@ public sealed partial class IslandsShellViewModel : ViewModelBase, IDisposable
         {
             _dialogs = value;
             if (Lists is not null) Lists.Dialogs = value;
+            if (Tasks is not null) Tasks.Dialogs = value;
         }
     }
 
diff --git a/src/ClaudeDo.Ui/Views/Islands/ListsIslandView.axaml b/src/ClaudeDo.Ui/Views/Islands/ListsIslandView.axaml
index 8b03f562..456f36ce 100644
--- a/src/ClaudeDo.Ui/Views/Islands/ListsIslandView.axaml
+++ b/src/ClaudeDo.Ui/Views/Islands/ListsIslandView.axaml
@@ -116,6 +116,7 @@
                         IsVisible="{Binding DropHintAbove}"/>
 
               <Border Grid.Row="1" Classes="list-item" Classes.active="{Binding IsActive}"
+                      Classes.drop-target="{Binding IsTaskDropTarget}"
                       Tapped="OnItemTapped"
                       DragDrop.AllowDrop="True"
                       DragDrop.DragOver="OnListDragOver"
diff --git a/src/ClaudeDo.Ui/Views/Islands/TasksIslandView.axaml.cs b/src/ClaudeDo.Ui/Views/Islands/TasksIslandView.axaml.cs
index 464b3773..f9e43757 100644
--- a/src/ClaudeDo.Ui/Views/Islands/TasksIslandView.axaml.cs
+++ b/src/ClaudeDo.Ui/Views/Islands/TasksIslandView.axaml.cs
@@ -31,6 +31,9 @@ public partial class TasksIslandView : UserControl
     private bool _dragArmed;
     private bool _dragging;
 
+    // The list row (in the Lists island) currently highlighted as a drop target while dragging.
+    private ListNavItemViewModel? _hintedList;
+
     public TasksIslandView()
     {
         InitializeComponent();
@@ -170,6 +173,7 @@ public partial class TasksIslandView : UserControl
         {
             _drag.MoveTo(this.PointToScreen(e.GetPosition(this)));
             UpdateReorderHint(e, topLevel);
+            UpdateListDropHint(e, topLevel);
         }
     }
 
@@ -205,7 +209,17 @@ public partial class TasksIslandView : UserControl
             return;
         }
 
-        // 2) Released over another row in the same user list → reorder.
+        // 2) Released over another user list in the Lists island → move the task there.
+        if (DataContext is TasksIslandViewModel vmMove
+            && ListItemUnder(e, topLevel) is { } targetList
+            && targetList.Kind == ListKind.User
+            && targetList.Id != vmMove.CurrentListId)
+        {
+            await vmMove.MoveTaskToListAsync(row, targetList);
+            return;
+        }
+
+        // 3) Released over another row in the same user list → reorder.
         if (DataContext is TasksIslandViewModel vm && vm.CanReorder)
         {
             var targetButton = RowButtonAt(e, topLevel);
@@ -218,7 +232,7 @@ public partial class TasksIslandView : UserControl
             }
         }
 
-        // 3) Anywhere else → cancel; EndDrag already restored the source row.
+        // 4) Anywhere else → cancel; EndDrag already restored the source row.
     }
 
     private void OnPointerCaptureLost(object? sender, PointerCaptureLostEventArgs e)
@@ -229,6 +243,7 @@ public partial class TasksIslandView : UserControl
         if (!_dragArmed && !_dragging) return;
         if (_pressRow is not null) _pressRow.IsDragging = false;
         if (DataContext is TasksIslandViewModel vm) vm.ClearDropHints();
+        ClearListDropHint();
         _drag.End();
         ResetPressState();
     }
@@ -237,6 +252,7 @@ public partial class TasksIslandView : UserControl
     {
         if (_pressRow is not null) _pressRow.IsDragging = false;
         if (DataContext is TasksIslandViewModel vm) vm.ClearDropHints();
+        ClearListDropHint();
         _drag.End();
         if (_dragging) e.Pointer.Capture(null);
         ResetPressState();
@@ -295,6 +311,44 @@ public partial class TasksIslandView : UserControl
         return button?.DataContext is TaskRowViewModel ? button : null;
     }
 
+    // The list-row Border under the cursor (Lists island), found the same way as RowButtonAt but
+    // walking up to a Border with the "list-item" style class (mirrors ListsIslandView's own
+    // FindListItemBorder) — the task drag has the pointer captured here, so a DragEventArgs never
+    // reaches the Lists island's own DragDrop.DragOver/Drop handlers.
+    private static ListNavItemViewModel? ListItemUnder(PointerEventArgs e, TopLevel topLevel)
+    {
+        var pt = e.GetPosition((Visual)topLevel);
+        Visual? v = topLevel.InputHitTest(pt) as Visual;
+        while (v is not null)
+        {
+            if (v is Border b && b.Classes.Contains("list-item"))
+                return b.DataContext as ListNavItemViewModel;
+            v = v.GetVisualParent();
+        }
+        return null;
+    }
+
+    // Live drop-hint while dragging over a candidate target list row.
+    private void UpdateListDropHint(PointerEventArgs e, TopLevel topLevel)
+    {
+        if (DataContext is not TasksIslandViewModel vm) { ClearListDropHint(); return; }
+
+        var target = ListItemUnder(e, topLevel);
+        if (target is null || target.Kind != ListKind.User || target.Id == vm.CurrentListId)
+            target = null;
+
+        if (ReferenceEquals(_hintedList, target)) return;
+        if (_hintedList is not null) _hintedList.IsTaskDropTarget = false;
+        _hintedList = target;
+        if (_hintedList is not null) _hintedList.IsTaskDropTarget = true;
+    }
+
+    private void ClearListDropHint()
+    {
+        if (_hintedList is not null) _hintedList.IsTaskDropTarget = false;
+        _hintedList = null;
+    }
+
     // The Mission Control view model whose window contains the release point, if any.
     private static MissionControlViewModel? MissionControlUnder(PixelPoint screen)
     {
diff --git a/tests/ClaudeDo.Data.Tests/MoveToListTests.cs b/tests/ClaudeDo.Data.Tests/MoveToListTests.cs
new file mode 100644
index 00000000..5e4b8fa7
--- /dev/null
+++ b/tests/ClaudeDo.Data.Tests/MoveToListTests.cs
@@ -0,0 +1,143 @@
+using ClaudeDo.Data;
+using ClaudeDo.Data.Models;
+using ClaudeDo.Data.Repositories;
+using Microsoft.EntityFrameworkCore;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Data.Tests;
+
+public sealed class MoveToListTests : IDisposable
+{
+    private readonly string _dbPath;
+    private readonly ClaudeDoDbContext _ctx;
+
+    public MoveToListTests()
+    {
+        _dbPath = Path.Combine(Path.GetTempPath(), $"claudedo_movelist_{Guid.NewGuid():N}.db");
+        var options = new DbContextOptionsBuilder<ClaudeDoDbContext>()
+            .UseSqlite($"Data Source={_dbPath}")
+            .Options;
+        _ctx = new ClaudeDoDbContext(options);
+        _ctx.Database.EnsureCreated();
+    }
+
+    public void Dispose()
+    {
+        _ctx.Dispose();
+        try { File.Delete(_dbPath); } catch { }
+        try { File.Delete(_dbPath + "-wal"); } catch { }
+        try { File.Delete(_dbPath + "-shm"); } catch { }
+    }
+
+    private async Task SeedListsAsync(params string[] ids)
+    {
+        foreach (var id in ids)
+            _ctx.Lists.Add(new ListEntity { Id = id, Name = id, CreatedAt = DateTime.UtcNow });
+        await _ctx.SaveChangesAsync();
+    }
+
+    [Fact]
+    public async Task MoveToList_changes_ListId_and_appends_at_end_of_target()
+    {
+        await SeedListsAsync("source", "target");
+        _ctx.Tasks.Add(new TaskEntity
+        {
+            Id = "t1", ListId = "source", Title = "Task", CreatedAt = DateTime.UtcNow, SortOrder = 0,
+        });
+        // Existing tasks already in the target list, so we can assert the moved task lands after them.
+        _ctx.Tasks.Add(new TaskEntity
+        {
+            Id = "existing1", ListId = "target", Title = "Existing 1", CreatedAt = DateTime.UtcNow, SortOrder = 0,
+        });
+        _ctx.Tasks.Add(new TaskEntity
+        {
+            Id = "existing2", ListId = "target", Title = "Existing 2", CreatedAt = DateTime.UtcNow, SortOrder = 1,
+        });
+        await _ctx.SaveChangesAsync();
+        _ctx.ChangeTracker.Clear();
+
+        await new TaskRepository(_ctx).MoveToListAsync("t1", "target");
+
+        var moved = await _ctx.Tasks.AsNoTracking().FirstAsync(t => t.Id == "t1");
+        Assert.Equal("target", moved.ListId);
+        Assert.Equal(2, moved.SortOrder);
+    }
+
+    [Fact]
+    public async Task MoveToList_moves_all_descendants_recursively()
+    {
+        await SeedListsAsync("source", "target");
+        _ctx.Tasks.Add(new TaskEntity
+        {
+            Id = "parent", ListId = "source", Title = "Parent", CreatedAt = DateTime.UtcNow, SortOrder = 0,
+        });
+        _ctx.Tasks.Add(new TaskEntity
+        {
+            Id = "child", ListId = "source", Title = "Child", CreatedAt = DateTime.UtcNow,
+            SortOrder = 1, ParentTaskId = "parent",
+        });
+        _ctx.Tasks.Add(new TaskEntity
+        {
+            Id = "grandchild", ListId = "source", Title = "Grandchild", CreatedAt = DateTime.UtcNow,
+            SortOrder = 2, ParentTaskId = "child",
+        });
+        await _ctx.SaveChangesAsync();
+        _ctx.ChangeTracker.Clear();
+
+        await new TaskRepository(_ctx).MoveToListAsync("parent", "target");
+
+        var all = await _ctx.Tasks.AsNoTracking()
+            .Where(t => t.Id == "parent" || t.Id == "child" || t.Id == "grandchild")
+            .ToListAsync();
+
+        Assert.All(all, t => Assert.Equal("target", t.ListId));
+    }
+
+    [Fact]
+    public async Task MoveToList_first_task_in_empty_target_gets_SortOrder_zero()
+    {
+        await SeedListsAsync("source", "target");
+        _ctx.Tasks.Add(new TaskEntity
+        {
+            Id = "t1", ListId = "source", Title = "Task", CreatedAt = DateTime.UtcNow, SortOrder = 3,
+        });
+        await _ctx.SaveChangesAsync();
+        _ctx.ChangeTracker.Clear();
+
+        await new TaskRepository(_ctx).MoveToListAsync("t1", "target");
+
+        var moved = await _ctx.Tasks.AsNoTracking().FirstAsync(t => t.Id == "t1");
+        Assert.Equal("target", moved.ListId);
+        Assert.Equal(0, moved.SortOrder);
+    }
+
+    // A corrupt parent chain must not hang the descendant walk.
+    [Fact(Timeout = 15000)]
+    public async Task MoveToList_survives_a_self_parenting_task()
+    {
+        await SeedListsAsync("source", "target");
+        _ctx.Tasks.Add(new TaskEntity
+        {
+            Id = "t1", ListId = "source", Title = "Task", CreatedAt = DateTime.UtcNow, SortOrder = 0,
+        });
+        await _ctx.SaveChangesAsync();
+        // Set the cycle after insert — the FK tolerates it, the walk must too.
+        await _ctx.Tasks.Where(t => t.Id == "t1")
+            .ExecuteUpdateAsync(s => s.SetProperty(t => t.ParentTaskId, "t1"));
+        _ctx.ChangeTracker.Clear();
+
+        await new TaskRepository(_ctx).MoveToListAsync("t1", "target");
+
+        var moved = await _ctx.Tasks.AsNoTracking().FirstAsync(t => t.Id == "t1");
+        Assert.Equal("target", moved.ListId);
+    }
+
+    [Fact]
+    public async Task MoveToList_throws_when_task_missing()
+    {
+        await SeedListsAsync("source", "target");
+
+        await Assert.ThrowsAsync<InvalidOperationException>(() =>
+            new TaskRepository(_ctx).MoveToListAsync("nope", "target"));
+    }
+}
diff --git a/tests/ClaudeDo.Ui.Tests/ViewModels/TasksIslandMoveToListTests.cs b/tests/ClaudeDo.Ui.Tests/ViewModels/TasksIslandMoveToListTests.cs
new file mode 100644
index 00000000..ed7cfa2c
--- /dev/null
+++ b/tests/ClaudeDo.Ui.Tests/ViewModels/TasksIslandMoveToListTests.cs
@@ -0,0 +1,346 @@
+using ClaudeDo.Data;
+using ClaudeDo.Data.Models;
+using ClaudeDo.Ui.Services;
+using ClaudeDo.Ui.ViewModels;
+using ClaudeDo.Ui.ViewModels.Conflicts;
+using ClaudeDo.Ui.ViewModels.Islands;
+using ClaudeDo.Ui.ViewModels.Modals;
+using Microsoft.EntityFrameworkCore;
+using TaskStatus = ClaudeDo.Data.Models.TaskStatus;
+
+namespace ClaudeDo.Ui.Tests.ViewModels;
+
+public class TasksIslandMoveToListTests : IDisposable
+{
+    private readonly string _dbPath;
+
+    public TasksIslandMoveToListTests()
+    {
+        _dbPath = Path.Combine(Path.GetTempPath(), $"claudedo_movetolist_{Guid.NewGuid():N}.db");
+        using var ctx = NewContext();
+        ctx.Database.EnsureCreated();
+    }
+
+    public void Dispose()
+    {
+        try { File.Delete(_dbPath); } catch { }
+        try { File.Delete(_dbPath + "-wal"); } catch { }
+        try { File.Delete(_dbPath + "-shm"); } catch { }
+    }
+
+    private ClaudeDoDbContext NewContext()
+    {
+        var opts = new DbContextOptionsBuilder<ClaudeDoDbContext>()
+            .UseSqlite($"Data Source={_dbPath}")
+            .Options;
+        return new ClaudeDoDbContext(opts);
+    }
+
+    private sealed class TestDbFactory : IDbContextFactory<ClaudeDoDbContext>
+    {
+        private readonly Func<ClaudeDoDbContext> _create;
+        public TestDbFactory(Func<ClaudeDoDbContext> create) => _create = create;
+        public ClaudeDoDbContext CreateDbContext() => _create();
+    }
+
+    private sealed class FakeDialogService : IDialogService
+    {
+        public bool ConfirmResult;
+        public int ConfirmCalls;
+        public string? LastMessage;
+
+        public Task<bool> ConfirmAsync(string message)
+        {
+            ConfirmCalls++;
+            LastMessage = message;
+            return Task.FromResult(ConfirmResult);
+        }
+
+        public Task ShowAboutAsync(AboutModalViewModel vm) => throw new NotImplementedException();
+        public Task ShowWeeklyReportAsync(WeeklyReportModalViewModel vm) => throw new NotImplementedException();
+        public Task ShowSettingsAsync(SettingsModalViewModel vm) => throw new NotImplementedException();
+        public Task ShowListSettingsAsync(ListSettingsModalViewModel vm) => throw new NotImplementedException();
+        public Task ShowRepoImportAsync(RepoImportModalViewModel vm) => throw new NotImplementedException();
+        public Task ShowWorktreesOverviewAsync(WorktreesOverviewModalViewModel vm) => throw new NotImplementedException();
+        public Task<IReadOnlyList<string>?> ShowMergeHelperSelectionAsync(MergeHelperSelectionModalViewModel vm) => throw new NotImplementedException();
+        public Task ShowWorkerConnectionAsync(WorkerConnectionModalViewModel vm) => throw new NotImplementedException();
+        public Task ShowConflictResolverAsync(ConflictResolverViewModel vm) => throw new NotImplementedException();
+        public Task ShowLogVisualizerAsync(LogVisualizerViewModel vm) => throw new NotImplementedException();
+        public Task ShowErrorAsync(string message) => Task.CompletedTask;
+        public void ShowMissionControl(MissionControlViewModel vm) => throw new NotImplementedException();
+        public void ShowDetachedMonitor(TaskMonitorViewModel monitor, Action onClosed) => throw new NotImplementedException();
+    }
+
+    private TasksIslandViewModel BuildViewModel() => new(new TestDbFactory(NewContext), worker: null);
+
+    private async Task SeedListsAsync(string? sourceDir = null, string? targetDir = null)
+    {
+        await using var db = NewContext();
+        db.Lists.Add(new ListEntity { Id = "source", Name = "Source", CreatedAt = DateTime.UtcNow, WorkingDir = sourceDir });
+        db.Lists.Add(new ListEntity { Id = "target", Name = "Target", CreatedAt = DateTime.UtcNow, WorkingDir = targetDir });
+        await db.SaveChangesAsync();
+    }
+
+    private async Task SeedTaskAsync(string id, TaskStatus status, string listId = "source", string? parentTaskId = null)
+    {
+        await using var db = NewContext();
+        db.Tasks.Add(new TaskEntity
+        {
+            Id = id, ListId = listId, Title = id, CreatedAt = DateTime.UtcNow,
+            Status = status, ParentTaskId = parentTaskId, SortOrder = 0,
+        });
+        await db.SaveChangesAsync();
+    }
+
+    private async Task SeedWorktreeAsync(string taskId, WorktreeState state)
+    {
+        await using var db = NewContext();
+        db.Worktrees.Add(new WorktreeEntity
+        {
+            TaskId = taskId, Path = $"C:/wt/{taskId}", BranchName = $"task/{taskId}",
+            BaseCommit = "abc123", State = state, CreatedAt = DateTime.UtcNow,
+        });
+        await db.SaveChangesAsync();
+    }
+
+    private static ListNavItemViewModel SourceList(string? workingDir = null) =>
+        new() { Id = "user:source", Kind = ListKind.User, Name = "Source", WorkingDir = workingDir };
+
+    private static ListNavItemViewModel TargetList(string? workingDir = null) =>
+        new() { Id = "user:target", Kind = ListKind.User, Name = "Target", WorkingDir = workingDir };
+
+    private static async Task LoadAndWaitAsync(TasksIslandViewModel vm, ListNavItemViewModel list)
+    {
+        vm.LoadForList(list);
+        var deadline = DateTime.UtcNow.AddSeconds(5);
+        while (DateTime.UtcNow < deadline)
+        {
+            await Task.Delay(25);
+            if (vm.Items.Count > 0) break;
+        }
+        await Task.Delay(50);
+    }
+
+    private async Task<TaskEntity> GetTaskAsync(string id)
+    {
+        await using var db = NewContext();
+        return await db.Tasks.AsNoTracking().FirstAsync(t => t.Id == id);
+    }
+
+    [Fact]
+    public async Task Move_RunningTask_IsRejected_AndReportsError()
+    {
+        await SeedListsAsync();
+        await SeedTaskAsync("t1", TaskStatus.Running);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList());
+        string? error = null;
+        vm.ErrorReported += msg => error = msg;
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        await vm.MoveTaskToListAsync(row, TargetList());
+
+        Assert.NotNull(error);
+        var entity = await GetTaskAsync("t1");
+        Assert.Equal("source", entity.ListId);
+    }
+
+    [Fact]
+    public async Task Move_TaskWithActiveWorktree_IsRejected_AndReportsError_EvenSameRepo()
+    {
+        var dir = "C:/repo";
+        await SeedListsAsync(dir, dir);
+        await SeedTaskAsync("t1", TaskStatus.Idle);
+        await SeedWorktreeAsync("t1", WorktreeState.Active);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList(dir));
+        string? error = null;
+        vm.ErrorReported += msg => error = msg;
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        await vm.MoveTaskToListAsync(row, TargetList(dir));
+
+        Assert.NotNull(error);
+        var entity = await GetTaskAsync("t1");
+        Assert.Equal("source", entity.ListId);
+    }
+
+    [Fact]
+    public async Task Move_DescendantWithKeptWorktree_IsRejected()
+    {
+        await SeedListsAsync();
+        await SeedTaskAsync("parent", TaskStatus.Idle);
+        await SeedTaskAsync("child", TaskStatus.Idle, parentTaskId: "parent");
+        await SeedWorktreeAsync("child", WorktreeState.Kept);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList());
+        string? error = null;
+        vm.ErrorReported += msg => error = msg;
+
+        var row = vm.Items.First(r => r.Id == "parent");
+        await vm.MoveTaskToListAsync(row, TargetList());
+
+        Assert.NotNull(error);
+        var entity = await GetTaskAsync("parent");
+        Assert.Equal("source", entity.ListId);
+    }
+
+    [Fact]
+    public async Task Move_SameWorkingDir_MovesWithoutConfirmDialog()
+    {
+        var dir = "C:/repo";
+        await SeedListsAsync(dir, dir);
+        await SeedTaskAsync("t1", TaskStatus.Idle);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList(dir));
+        var dialogs = new FakeDialogService();
+        vm.Dialogs = dialogs;
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        await vm.MoveTaskToListAsync(row, TargetList(dir));
+
+        Assert.Equal(0, dialogs.ConfirmCalls);
+        var entity = await GetTaskAsync("t1");
+        Assert.Equal("target", entity.ListId);
+    }
+
+    [Fact]
+    public async Task Move_BothWithoutWorkingDir_MovesWithoutConfirmDialog()
+    {
+        await SeedListsAsync();
+        await SeedTaskAsync("t1", TaskStatus.Idle);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList());
+        var dialogs = new FakeDialogService();
+        vm.Dialogs = dialogs;
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        await vm.MoveTaskToListAsync(row, TargetList());
+
+        Assert.Equal(0, dialogs.ConfirmCalls);
+        var entity = await GetTaskAsync("t1");
+        Assert.Equal("target", entity.ListId);
+    }
+
+    [Fact]
+    public async Task Move_DifferentWorkingDir_AsksConfirmation_MovesOnConfirm()
+    {
+        await SeedListsAsync("C:/repoA", "C:/repoB");
+        await SeedTaskAsync("t1", TaskStatus.Idle);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList("C:/repoA"));
+        var dialogs = new FakeDialogService { ConfirmResult = true };
+        vm.Dialogs = dialogs;
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        await vm.MoveTaskToListAsync(row, TargetList("C:/repoB"));
+
+        Assert.Equal(1, dialogs.ConfirmCalls);
+        var entity = await GetTaskAsync("t1");
+        Assert.Equal("target", entity.ListId);
+    }
+
+    [Fact]
+    public async Task Move_DifferentWorkingDir_CancelledConfirmation_DoesNotMove()
+    {
+        await SeedListsAsync("C:/repoA", "C:/repoB");
+        await SeedTaskAsync("t1", TaskStatus.Idle);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList("C:/repoA"));
+        var dialogs = new FakeDialogService { ConfirmResult = false };
+        vm.Dialogs = dialogs;
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        await vm.MoveTaskToListAsync(row, TargetList("C:/repoB"));
+
+        Assert.Equal(1, dialogs.ConfirmCalls);
+        var entity = await GetTaskAsync("t1");
+        Assert.Equal("source", entity.ListId);
+    }
+
+    [Fact]
+    public async Task Move_TargetIsCurrentList_IsNoOp()
+    {
+        await SeedListsAsync();
+        await SeedTaskAsync("t1", TaskStatus.Idle);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList());
+        var dialogs = new FakeDialogService();
+        vm.Dialogs = dialogs;
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        await vm.MoveTaskToListAsync(row, SourceList());
+
+        Assert.Equal(0, dialogs.ConfirmCalls);
+        var entity = await GetTaskAsync("t1");
+        Assert.Equal("source", entity.ListId);
+    }
+
+    [Fact]
+    public async Task Move_DifferentWorkingDir_ConfirmMessageNamesBothRepos()
+    {
+        await SeedListsAsync("C:/repoA", "C:/repoB");
+        await SeedTaskAsync("t1", TaskStatus.Idle);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList("C:/repoA"));
+        var dialogs = new FakeDialogService { ConfirmResult = false };
+        vm.Dialogs = dialogs;
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        await vm.MoveTaskToListAsync(row, TargetList("C:/repoB"));
+
+        Assert.NotNull(dialogs.LastMessage);
+        Assert.Contains("C:/repoA", dialogs.LastMessage);
+        Assert.Contains("C:/repoB", dialogs.LastMessage);
+    }
+
+    // The source repo comes from the task's own list, not from the island's current list — those
+    // differ whenever a smart/virtual list is shown, and a wrong source dir would ask (or skip
+    // asking) for confirmation at the wrong times.
+    [Fact]
+    public async Task Move_SourceRepoIsReadFromTaskOwnList_NotCurrentList()
+    {
+        await SeedListsAsync("C:/repoA", "C:/repoA");
+        await SeedTaskAsync("t1", TaskStatus.Idle);
+
+        var vm = BuildViewModel();
+        // Island shows a virtual list carrying no working dir of its own.
+        await LoadAndWaitAsync(vm, SourceList(workingDir: null));
+        var dialogs = new FakeDialogService { ConfirmResult = true };
+        vm.Dialogs = dialogs;
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        await vm.MoveTaskToListAsync(row, TargetList("C:/repoA"));
+
+        // Both lists really are the same repo, so no confirmation should have been needed.
+        Assert.Equal(0, dialogs.ConfirmCalls);
+        var entity = await GetTaskAsync("t1");
+        Assert.Equal("target", entity.ListId);
+    }
+
+    [Fact]
+    public async Task Move_TargetIsSmartList_IsNoOp()
+    {
+        await SeedListsAsync();
+        await SeedTaskAsync("t1", TaskStatus.Idle);
+
+        var vm = BuildViewModel();
+        await LoadAndWaitAsync(vm, SourceList());
+
+        var row = vm.Items.First(r => r.Id == "t1");
+        var smart = new ListNavItemViewModel { Id = "smart:my-day", Kind = ListKind.Smart, Name = "My Day" };
+        await vm.MoveTaskToListAsync(row, smart);
+
+        var entity = await GetTaskAsync("t1");
+        Assert.Equal("source", entity.ListId);
+    }
+}