diff --git a/cc-haha/desktop/src/components/chat/ChatInput.tsx b/cc-haha/desktop/src/components/chat/ChatInput.tsx
index 7dbf3a4..73765b7 100644
--- a/cc-haha/desktop/src/components/chat/ChatInput.tsx
+++ b/cc-haha/desktop/src/components/chat/ChatInput.tsx
@@ -562,9 +562,9 @@ export function ChatInput({ variant = 'default' }: ChatInputProps) {
               filter={atFilter}
               onSelect={(_path, name) => {
                 if (atCursorPos >= 0) {
-                  // Insert name at cursor position, replacing filter text
-                  const newValue = `${input.slice(0, atCursorPos)}${name}${input.slice(atCursorPos)}`
-                  const newCursorPos = atCursorPos + name.length
+                  const atStart = atCursorPos - atFilter.length - 1
+                  const newValue = `${input.slice(0, atStart)}${name}${input.slice(atCursorPos)}`
+                  const newCursorPos = atStart + name.length
                   setInput(newValue)
                   setFileSearchOpen(false)
                   setAtFilter('')