diff --git a/web/src/features/groups/GroupDetailColumn.tsx b/web/src/features/groups/GroupDetailColumn.tsx
index b24acde5..4ab6b416 100644
--- a/web/src/features/groups/GroupDetailColumn.tsx
+++ b/web/src/features/groups/GroupDetailColumn.tsx
@@ -214,7 +214,16 @@ export function GroupDetailColumn({ topicId, peerName, onClose, onOpenHistory }:
   });
 
   const clearHistory = async () => {
-    if (!(await requestConfirm({ message: '确定清空本群的聊天记录吗？此操作仅清除本地记录，不影响其他成员。', danger: true }))) return;
+    // See DetailColumn.tsx's identical clearHistory for why this copy changed: a soft delete
+    // (`delMessagesAll(false)`) is a real, per-account server watermark (im_be's Topic.replyDelMsg),
+    // not a local-only cache wipe a refresh or another device would undo.
+    if (
+      !(await requestConfirm({
+        message: '确定清空本群的聊天记录吗？清空后，你的账号（含其他设备）将无法再看到这些消息，且无法恢复；不影响其他成员。',
+        danger: true,
+      }))
+    )
+      return;
     try {
       await tinode.getTopic(topicId).delMessagesAll(false);
     } catch (err) {
diff --git a/web/src/features/messages/DetailColumn.tsx b/web/src/features/messages/DetailColumn.tsx
index c7e036d5..fcd5d8d8 100644
--- a/web/src/features/messages/DetailColumn.tsx
+++ b/web/src/features/messages/DetailColumn.tsx
@@ -160,7 +160,19 @@ export function DetailColumn({ topicId, peerName, onClose, onOpenHistory }: Deta
   });
 
   const clearHistory = async () => {
-    if (!(await requestConfirm({ message: '确定清空与该联系人的聊天记录吗？此操作仅清除本地记录，不影响对方。', danger: true }))) return;
+    // The old copy here ("此操作仅清除本地记录") was actively misleading -- confirmed by reading
+    // the real backend handler (im_be's Topic.replyDelMsg): a soft delete (`hardDel=false`, what
+    // `delMessagesAll(false)` sends) is NOT a browser-local cache wipe a refresh would undo. The
+    // server records a per-account delete watermark (`t.perUser[asUid].delID`) that persists across
+    // every device/session on this account and isn't reversible through any normal client action --
+    // only "does it affect the other party" (no) was actually true about the old wording.
+    if (
+      !(await requestConfirm({
+        message: '确定清空与该联系人的聊天记录吗？清空后，你的账号（含其他设备）将无法再看到这些消息，且无法恢复；不影响对方。',
+        danger: true,
+      }))
+    )
+      return;
     tinode.getTopic(topicId).delMessagesAll(false);
   };