diff --git a/dist-electron/main/main.js b/dist-electron/main/main.js
index 2400e83..d8adec3 100644
--- a/dist-electron/main/main.js
+++ b/dist-electron/main/main.js
@@ -1,6 +1,6 @@
 "use strict";
 require("electron");
-require("./main-DfEXs_ww.js");
+require("./main-CDQKuYIF.js");
 require("electron-squirrel-startup");
 require("electron-log");
 require("bytenode");
diff --git a/electron/gateway/manager.ts b/electron/gateway/manager.ts
index 582bc38..8bfe015 100644
--- a/electron/gateway/manager.ts
+++ b/electron/gateway/manager.ts
@@ -798,6 +798,10 @@ class GatewayManager {
       }
       case 'session.delete': {
         const request = params as GatewayRpcParams['session.delete'];
+        if (normalizeAgentSessionKey(request.sessionKey).endsWith(':main')) {
+          return { success: false };
+        }
+
         await this.rpcGateway('sessions.delete', {
           key: normalizeAgentSessionKey(request.sessionKey),
           deleteTranscript: true,
diff --git a/src/components/chat/ChatHistoryPanel.tsx b/src/components/chat/ChatHistoryPanel.tsx
index 7ca5680..22033d0 100644
--- a/src/components/chat/ChatHistoryPanel.tsx
+++ b/src/components/chat/ChatHistoryPanel.tsx
@@ -206,6 +206,7 @@ function ChatHistoryPanel({
                         {bucket.sessions.map((session) => {
                           const isActive = session.conversationId === selectedConversationId;
                           const isMenuOpen = menuState?.conversationId === session.conversationId;
+                          const canDelete = Boolean(onDeleteConversation) && session.canDelete !== false;
 
                           return (
                             <li key={session.conversationId}>
@@ -273,19 +274,20 @@ function ChatHistoryPanel({
                                       <PencilLine className="h-4 w-4 text-[#94a3b8]" />
                                       {t('conversation.historyPanel.rename')}
                                     </button>
-                                    <button
-                                      type="button"
-                                      className="flex w-full items-center gap-2 border-t border-[#eef3f9] px-3 py-2.5 text-left text-sm text-[#ef4444] transition-colors hover:bg-[#fff5f5] disabled:cursor-not-allowed disabled:text-[#f5a2a2] dark:border-[#2f3136] dark:hover:bg-[#2a2a2d]"
-                                      disabled={!onDeleteConversation}
-                                      onClick={(event) => {
-                                        event.stopPropagation();
-                                        setMenuState(null);
-                                        onDeleteConversation?.(session.conversationId);
-                                      }}
-                                    >
-                                      <Trash2 className="h-4 w-4" />
-                                      {t('conversation.historyPanel.delete')}
-                                    </button>
+                                    {canDelete ? (
+                                      <button
+                                        type="button"
+                                        className="flex w-full items-center gap-2 border-t border-[#eef3f9] px-3 py-2.5 text-left text-sm text-[#ef4444] transition-colors hover:bg-[#fff5f5] disabled:cursor-not-allowed disabled:text-[#f5a2a2] dark:border-[#2f3136] dark:hover:bg-[#2a2a2d]"
+                                        onClick={(event) => {
+                                          event.stopPropagation();
+                                          setMenuState(null);
+                                          onDeleteConversation?.(session.conversationId);
+                                        }}
+                                      >
+                                        <Trash2 className="h-4 w-4" />
+                                        {t('conversation.historyPanel.delete')}
+                                      </button>
+                                    ) : null}
                                   </div>
                                 ) : null}
                               </div>
diff --git a/src/components/chat/ChatMessageList.tsx b/src/components/chat/ChatMessageList.tsx
index a2fffd9..cfb60b1 100644
--- a/src/components/chat/ChatMessageList.tsx
+++ b/src/components/chat/ChatMessageList.tsx
@@ -101,8 +101,8 @@ function ChatMessageList({ messages, loading, showWelcomeState }: ChatMessageLis
   }, [loading, messages]);
 
   return (
-    <div className="flex min-h-0 flex-1 flex-col overflow-hidden px-4 py-6 dark:bg-[#161618] sm:px-6">
-      <div ref={containerRef} className="mx-auto flex min-h-0 w-full flex-1 flex-col gap-5 overflow-y-auto pr-1">
+    <div className="flex min-h-0 flex-1 flex-col overflow-hidden p-4 dark:bg-[#161618] sm:px-6">
+      <div ref={containerRef} className="mx-auto flex min-h-0 w-full flex-1 flex-col gap-5 overflow-y-auto pr-2">
         {loading ? (
           <div className="w-full rounded-[18px] border border-dashed border-[#DDD3C3] bg-[#EFE7D8] px-4 py-3 text-sm text-[#645C50] dark:border-white/10 dark:bg-white/5 dark:text-gray-400">
             {t('conversation.messageList.loading')}
diff --git a/src/components/chat/types.ts b/src/components/chat/types.ts
index 4d629be..6351ca6 100644
--- a/src/components/chat/types.ts
+++ b/src/components/chat/types.ts
@@ -9,6 +9,7 @@ export type ChatHistoryBucket = {
     conversationId: string;
     title: string;
     updatedAt: string;
+    canDelete?: boolean;
   }>;
 };
 
diff --git a/src/pages/Home/index.tsx b/src/pages/Home/index.tsx
index 768eccb..7a2f00e 100644
--- a/src/pages/Home/index.tsx
+++ b/src/pages/Home/index.tsx
@@ -120,6 +120,10 @@ function getTaskRoomTypeLabel(task: { roomType: string; roomList: Array<{ id?: s
   return matchedRoom?.pmsName || task.roomType;
 }
 
+function isProtectedMainSession(sessionKey: string): boolean {
+  return sessionKey.endsWith(':main');
+}
+
 function mapMessages(
   messages: RawMessage[],
   streamingMessage: RawMessage | null,
@@ -281,6 +285,7 @@ export default function HomePage() {
         conversationId: session.key,
         title: chatSessionLabels[session.key] || session.displayName || session.key,
         updatedAt: formatHistoryTime(locale, t, activityMs, currentMs),
+        canDelete: !isProtectedMainSession(session.key),
       });
     }
 
@@ -421,6 +426,10 @@ export default function HomePage() {
   }
 
   function handleDeleteConversation(conversationId: string): void {
+    if (isProtectedMainSession(conversationId)) {
+      return;
+    }
+
     const nextTitle = chatSessionLabels[conversationId]
       || chatSessions.find((session) => session.key === conversationId)?.displayName
       || t('conversation.untitledConversation');
@@ -433,6 +442,10 @@ export default function HomePage() {
 
   async function handleConfirmDeleteConversation(): Promise<void> {
     if (!deleteConversationTarget) return;
+    if (isProtectedMainSession(deleteConversationTarget.conversationId)) {
+      setDeleteConversationTarget(null);
+      return;
+    }
 
     setDeletingConversation(true);
     try {
diff --git a/src/stores/chat.ts b/src/stores/chat.ts
index 6c6d6b2..bea909c 100644
--- a/src/stores/chat.ts
+++ b/src/stores/chat.ts
@@ -197,6 +197,10 @@ function buildNewSessionKey(agentId: string | null | undefined): string {
   return buildAgentSessionKey(agentId || getDefaultAgentId(), `session-${Date.now()}`);
 }
 
+function isProtectedMainSession(sessionKey: string): boolean {
+  return normalizeAgentSessionKey(sessionKey).endsWith(':main');
+}
+
 function clearSessionEntryFromMap<T extends Record<string, unknown>>(entries: T, sessionKey: string): T {
   return Object.fromEntries(Object.entries(entries).filter(([key]) => key !== sessionKey)) as T;
 }
@@ -671,6 +675,10 @@ function selectAgent(agentId: string): void {
 }
 
 async function deleteSession(sessionKey: string): Promise<void> {
+  if (isProtectedMainSession(sessionKey)) {
+    return;
+  }
+
   const currentState = state;
   const isDeletingCurrentSession = sessionKey === currentState.currentSessionKey;