diff --git a/src/ClaudeDo.Worker/Hub/WorkerHub.cs b/src/ClaudeDo.Worker/Hub/WorkerHub.cs
index 959957c..96c4003 100644
--- a/src/ClaudeDo.Worker/Hub/WorkerHub.cs
+++ b/src/ClaudeDo.Worker/Hub/WorkerHub.cs
@@ -54,6 +54,7 @@ public record WorktreeOverviewDto(
 
 public record ForceRemoveResultDto(bool Removed, string? Reason);
 public record MergeResultDto(string Status, IReadOnlyList<string> ConflictFiles, string? ErrorMessage);
+public record MergePreviewDto(string Status, IReadOnlyList<string> ConflictFiles, int ChangedFileCount);
 public record MergeTargetsDto(string DefaultBranch, IReadOnlyList<string> LocalBranches);
 public record UpdateListDto(string Id, string Name, string? WorkingDir, string DefaultCommitType);
 public record UpdateListConfigDto(string ListId, string? Model, string? SystemPrompt, string? AgentPath, int? MaxTurns = null);
@@ -320,6 +321,13 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
             return new MergeTargetsDto(t.DefaultBranch, t.LocalBranches);
         });
 
+    public Task<MergePreviewDto> PreviewMerge(string taskId, string targetBranch)
+        => HubGuard(async () =>
+        {
+            var p = await _mergeService.PreviewAsync(taskId, targetBranch ?? "", CancellationToken.None);
+            return new MergePreviewDto(p.Status, p.ConflictFiles, p.ChangedFileCount);
+        });
+
     public async Task UpdateList(UpdateListDto dto)
     {
         using var ctx = _dbFactory.CreateDbContext();
@@ -384,11 +392,14 @@ public sealed class WorkerHub : Microsoft.AspNetCore.SignalR.Hub
         if (!result.Ok) throw new HubException(result.Reason ?? "set status failed");
     }
 
-    public async Task ApproveReview(string taskId)
-    {
-        var result = await _state.ApproveReviewAsync(taskId, Context.ConnectionAborted);
-        if (!result.Ok) throw new HubException(result.Reason ?? "approve failed");
-    }
+    public Task<MergeResultDto> ApproveReview(string taskId, string targetBranch)
+        => HubGuard(async () =>
+        {
+            var r = await _mergeService.ApproveAndMergeAsync(taskId, targetBranch ?? "", CancellationToken.None);
+            if (r.Status == TaskMergeService.StatusBlocked)
+                throw new HubException(r.ErrorMessage ?? "approve failed");
+            return new MergeResultDto(r.Status, r.ConflictFiles, r.ErrorMessage);
+        });
 
     public async Task RejectReviewToQueue(string taskId, string feedback)
     {