diff --git a/src/ClaudeDo.Ui/Services/Interfaces/IWorkerClient.cs b/src/ClaudeDo.Ui/Services/Interfaces/IWorkerClient.cs
index 3e0f8ebf..9b78e4bc 100644
--- a/src/ClaudeDo.Ui/Services/Interfaces/IWorkerClient.cs
+++ b/src/ClaudeDo.Ui/Services/Interfaces/IWorkerClient.cs
@@ -85,6 +85,9 @@ public interface IWorkerClient : INotifyPropertyChanged
     /// <summary>Launch spec for an ad-hoc interactive session in an arbitrary directory --
     /// no task, no worktree.</summary>
     Task<LaunchSpec> GetAdHocLaunchSpecAsync(string directory, CancellationToken ct = default);
+    /// <summary>Launch spec for an embedded ConPTY "merge helper" session that drives the given
+    /// tasks to a merged/Done state. listId scopes the session to that list; null = all lists.</summary>
+    Task<LaunchSpec> GetMergeHelperLaunchSpecAsync(IReadOnlyList<string> taskIds, string? listId, CancellationToken ct = default);
     /// <summary>Starts a planning session and returns the launch spec for an embedded ConPTY
     /// planning terminal (replaces StartPlanningSessionAsync's external wt window).</summary>
     Task<LaunchSpec> GetPlanningStartLaunchSpecAsync(string taskId, CancellationToken ct = default);
diff --git a/src/ClaudeDo.Ui/Services/WorkerClient.cs b/src/ClaudeDo.Ui/Services/WorkerClient.cs
index 5ce7adf6..16a1c971 100644
--- a/src/ClaudeDo.Ui/Services/WorkerClient.cs
+++ b/src/ClaudeDo.Ui/Services/WorkerClient.cs
@@ -522,6 +522,9 @@ public partial class WorkerClient : ObservableObject, IAsyncDisposable, IWorkerC
     public async Task<LaunchSpec> GetAdHocLaunchSpecAsync(string directory, CancellationToken ct = default)
         => await _hub.InvokeAsync<LaunchSpec>("GetAdHocLaunchSpec", directory, ct);
 
+    public async Task<LaunchSpec> GetMergeHelperLaunchSpecAsync(IReadOnlyList<string> taskIds, string? listId, CancellationToken ct = default)
+        => await _hub.InvokeAsync<LaunchSpec>("GetMergeHelperLaunchSpec", taskIds, listId, ct);
+
     public async Task<LaunchSpec> GetPlanningStartLaunchSpecAsync(string taskId, CancellationToken ct = default)
         => await _hub.InvokeAsync<LaunchSpec>("GetPlanningStartLaunchSpec", taskId, ct);
 
diff --git a/src/ClaudeDo.Worker/Hub/WorkerHub.cs b/src/ClaudeDo.Worker/Hub/WorkerHub.cs
index 7b2731a5..93cfc43c 100644
--- a/src/ClaudeDo.Worker/Hub/WorkerHub.cs
+++ b/src/ClaudeDo.Worker/Hub/WorkerHub.cs
@@ -676,6 +676,16 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         return _interactiveLaunchSpec.BuildForDirectoryAsync(directory, Context.ConnectionAborted);
     });
 
+    // Builds the launch spec for an embedded ConPTY "merge helper" session that drives the given
+    // tasks to a merged/Done state via the mcp__claudedo__* tools. listId scopes the brief label
+    // and cwd to that list; null means all lists.
+    public Task<LaunchSpec> GetMergeHelperLaunchSpec(string[] taskIds, string? listId) => HubGuard(() =>
+    {
+        if (_interactiveLaunchSpec is null)
+            throw new InvalidOperationException("Interactive launch spec service is not configured.");
+        return _interactiveLaunchSpec.BuildForMergeHelperAsync(taskIds, listId, Context.ConnectionAborted);
+    });
+
     // Starts a planning session (worktree + prompt files + token, task -> Planning) and returns
     // the launch spec for an embedded ConPTY planning terminal -- the ConPTY replacement for
     // StartPlanningSessionAsync's external wt window. On any spec-build failure the just-started
diff --git a/tests/ClaudeDo.Ui.Tests/StubWorkerClient.cs b/tests/ClaudeDo.Ui.Tests/StubWorkerClient.cs
index e13cafe8..7faea86c 100644
--- a/tests/ClaudeDo.Ui.Tests/StubWorkerClient.cs
+++ b/tests/ClaudeDo.Ui.Tests/StubWorkerClient.cs
@@ -100,6 +100,8 @@ public abstract class StubWorkerClient : IWorkerClient
         => Task.FromResult(new LaunchSpec(".", "claude", Array.Empty<string>(), new Dictionary<string, string>()));
     public virtual Task<LaunchSpec> GetAdHocLaunchSpecAsync(string directory, CancellationToken ct = default)
         => Task.FromResult(new LaunchSpec(directory, "claude", Array.Empty<string>(), new Dictionary<string, string>()));
+    public virtual Task<LaunchSpec> GetMergeHelperLaunchSpecAsync(IReadOnlyList<string> taskIds, string? listId, CancellationToken ct = default)
+        => Task.FromResult(new LaunchSpec(".", "claude", Array.Empty<string>(), new Dictionary<string, string>()));
     public virtual Task<LaunchSpec> GetPlanningStartLaunchSpecAsync(string taskId, CancellationToken ct = default)
         => Task.FromResult(new LaunchSpec(".", "claude", Array.Empty<string>(), new Dictionary<string, string>()));
     public virtual Task<LaunchSpec> GetPlanningResumeLaunchSpecAsync(string taskId, CancellationToken ct = default)
diff --git a/tests/ClaudeDo.Worker.Tests/UiVm/TasksIslandViewModelPlanningTests.cs b/tests/ClaudeDo.Worker.Tests/UiVm/TasksIslandViewModelPlanningTests.cs
index 60cdd73f..1bc6598c 100644
--- a/tests/ClaudeDo.Worker.Tests/UiVm/TasksIslandViewModelPlanningTests.cs
+++ b/tests/ClaudeDo.Worker.Tests/UiVm/TasksIslandViewModelPlanningTests.cs
@@ -75,6 +75,8 @@ sealed class FakeWorkerClient : IWorkerClient
     public Task SubmitTaskForReviewAsync(string taskId, CancellationToken ct = default) => Task.CompletedTask;
     public Task<LaunchSpec> GetInteractiveLaunchSpecAsync(string taskId, CancellationToken ct = default)
         => Task.FromResult(new LaunchSpec(".", "claude", Array.Empty<string>(), new Dictionary<string, string>()));
+    public Task<LaunchSpec> GetMergeHelperLaunchSpecAsync(IReadOnlyList<string> taskIds, string? listId, CancellationToken ct = default)
+        => Task.FromResult(new LaunchSpec(".", "claude", Array.Empty<string>(), new Dictionary<string, string>()));
     public Task<LaunchSpec> GetAdHocLaunchSpecAsync(string directory, CancellationToken ct = default)
         => Task.FromResult(new LaunchSpec(directory, "claude", Array.Empty<string>(), new Dictionary<string, string>()));
     public int PlanningStartSpecCalls { get; private set; }