diff --git a/src/main.ts b/src/main.ts
index e965661..fe84d73 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -153,6 +153,24 @@ interface CustomClip {
     filenameTemplate?: string;
 }
 
+interface MergeGroupItem {
+    url: string;
+    title: string;
+    date: string;
+    streamer: string;
+    duration_str: string;
+}
+
+interface MergeGroup {
+    items: MergeGroupItem[];
+    mergePhase: 'downloading' | 'merging' | 'splitting' | 'cleanup' | 'done';
+    currentItemIndex: number;
+    downloadedFiles: Record<number, string>;
+    mergedFile?: string;
+    splitFiles?: string[];
+    totalDurationSec?: number;
+}
+
 interface QueueItem {
     id: string;
     title: string;
@@ -170,6 +188,7 @@ interface QueueItem {
     totalBytes?: number;
     last_error?: string;
     customClip?: CustomClip;
+    mergeGroup?: MergeGroup;
 }
 
 interface DownloadResult {
diff --git a/src/preload.ts b/src/preload.ts
index e917eac..22df4c4 100644
--- a/src/preload.ts
+++ b/src/preload.ts
@@ -9,6 +9,24 @@ interface CustomClip {
     filenameTemplate?: string;
 }
 
+interface MergeGroupItem {
+    url: string;
+    title: string;
+    date: string;
+    streamer: string;
+    duration_str: string;
+}
+
+interface MergeGroup {
+    items: MergeGroupItem[];
+    mergePhase: 'downloading' | 'merging' | 'splitting' | 'cleanup' | 'done';
+    currentItemIndex: number;
+    downloadedFiles: Record<number, string>;
+    mergedFile?: string;
+    splitFiles?: string[];
+    totalDurationSec?: number;
+}
+
 interface QueueItem {
     id: string;
     title: string;
@@ -23,6 +41,7 @@ interface QueueItem {
     speed?: string;
     eta?: string;
     customClip?: CustomClip;
+    mergeGroup?: MergeGroup;
 }
 
 interface DownloadProgress {
diff --git a/src/renderer-globals.d.ts b/src/renderer-globals.d.ts
index d71cb44..2f1e244 100644
--- a/src/renderer-globals.d.ts
+++ b/src/renderer-globals.d.ts
@@ -37,6 +37,24 @@ interface CustomClip {
     filenameTemplate?: string;
 }
 
+interface MergeGroupItem {
+    url: string;
+    title: string;
+    date: string;
+    streamer: string;
+    duration_str: string;
+}
+
+interface MergeGroup {
+    items: MergeGroupItem[];
+    mergePhase: 'downloading' | 'merging' | 'splitting' | 'cleanup' | 'done';
+    currentItemIndex: number;
+    downloadedFiles: Record<number, string>;
+    mergedFile?: string;
+    splitFiles?: string[];
+    totalDurationSec?: number;
+}
+
 interface QueueItem {
     id: string;
     title: string;
@@ -55,6 +73,7 @@ interface QueueItem {
     progressStatus?: string;
     last_error?: string;
     customClip?: CustomClip;
+    mergeGroup?: MergeGroup;
 }
 
 interface DownloadProgress {
@@ -166,6 +185,7 @@ interface ApiBridge {
     reorderQueue(orderIds: string[]): Promise<QueueItem[]>;
     clearCompleted(): Promise<QueueItem[]>;
     retryFailedDownloads(): Promise<QueueItem[]>;
+    createMergeGroup(itemIds: string[]): Promise<QueueItem[]>;
     startDownload(): Promise<boolean>;
     pauseDownload(): Promise<boolean>;
     cancelDownload(): Promise<boolean>;