diff --git a/src/renderer/src/hooks/useTextareaResize.ts b/src/renderer/src/hooks/useTextareaResize.ts
index 8688cb186f..c29d6134cd 100644
--- a/src/renderer/src/hooks/useTextareaResize.ts
+++ b/src/renderer/src/hooks/useTextareaResize.ts
@@ -51,7 +51,7 @@ export function useTextareaResize(options: UseTextareaResizeOptions = {}): UseTe
   const { maxHeight = 400, minHeight = 30, autoResize = true } = options
 
   const textareaRef = useRef<TextAreaRef>(null)
-  const [customHeight, setCustomHeight] = useState<number>()
+  const [customHeight, setCustomHeight] = useState<number | undefined>(undefined)
   const [isExpanded, setIsExpanded] = useState(false)
 
   const resize = useCallback(
diff --git a/src/renderer/src/pages/home/Inputbar/AgentSessionInputbar.tsx b/src/renderer/src/pages/home/Inputbar/AgentSessionInputbar.tsx
index 2dbcd04067..850be7f727 100644
--- a/src/renderer/src/pages/home/Inputbar/AgentSessionInputbar.tsx
+++ b/src/renderer/src/pages/home/Inputbar/AgentSessionInputbar.tsx
@@ -177,8 +177,10 @@ const AgentSessionInputbarInner: FC<InnerProps> = ({ assistant, agentId, session
     resize: resizeTextArea,
     focus: focusTextarea,
     setExpanded,
-    isExpanded: textareaIsExpanded
-  } = useTextareaResize({ maxHeight: 400, minHeight: 30 })
+    isExpanded: textareaIsExpanded,
+    customHeight,
+    setCustomHeight
+  } = useTextareaResize({ maxHeight: 500, minHeight: 30 })
   const { sendMessageShortcut, apiServer } = useSettings()
 
   const { t } = useTranslation()
@@ -474,6 +476,8 @@ const AgentSessionInputbarInner: FC<InnerProps> = ({ assistant, agentId, session
       text={text}
       onTextChange={setText}
       textareaRef={textareaRef}
+      height={customHeight}
+      onHeightChange={setCustomHeight}
       resizeTextArea={resizeTextArea}
       focusTextarea={focusTextarea}
       placeholder={placeholderText}
diff --git a/src/renderer/src/pages/home/Inputbar/Inputbar.tsx b/src/renderer/src/pages/home/Inputbar/Inputbar.tsx
index 0985023ead..fc95082e50 100644
--- a/src/renderer/src/pages/home/Inputbar/Inputbar.tsx
+++ b/src/renderer/src/pages/home/Inputbar/Inputbar.tsx
@@ -143,9 +143,11 @@ const InputbarInner: FC<InputbarInnerProps> = ({ assistant: initialAssistant, se
     resize: resizeTextArea,
     focus: focusTextarea,
     setExpanded,
-    isExpanded: textareaIsExpanded
+    isExpanded: textareaIsExpanded,
+    customHeight,
+    setCustomHeight
   } = useTextareaResize({
-    maxHeight: 400,
+    maxHeight: 500,
     minHeight: 30
   })
 
@@ -257,7 +259,7 @@ const InputbarInner: FC<InputbarInnerProps> = ({ assistant: initialAssistant, se
       setText('')
       setFiles([])
       setTimeoutTimer('sendMessage_1', () => setText(''), 500)
-      setTimeoutTimer('sendMessage_2', () => resizeTextArea(true), 0)
+      setTimeoutTimer('sendMessage_2', () => resizeTextArea(), 0)
     } catch (error) {
       logger.warn('Failed to send message:', error as Error)
       parent?.recordException(error as Error)
@@ -478,6 +480,8 @@ const InputbarInner: FC<InputbarInnerProps> = ({ assistant: initialAssistant, se
       text={text}
       onTextChange={setText}
       textareaRef={textareaRef}
+      height={customHeight}
+      onHeightChange={setCustomHeight}
       resizeTextArea={resizeTextArea}
       focusTextarea={focusTextarea}
       isLoading={loading}
diff --git a/src/renderer/src/pages/home/Inputbar/components/InputbarCore.tsx b/src/renderer/src/pages/home/Inputbar/components/InputbarCore.tsx
index e1ae6d1bae..b55ca93cd3 100644
--- a/src/renderer/src/pages/home/Inputbar/components/InputbarCore.tsx
+++ b/src/renderer/src/pages/home/Inputbar/components/InputbarCore.tsx
@@ -50,6 +50,9 @@ export interface InputbarCoreProps {
   resizeTextArea: (force?: boolean) => void
   focusTextarea: () => void
 
+  height: number | undefined
+  onHeightChange: (height: number) => void
+
   supportedExts: string[]
   isLoading: boolean
 
@@ -104,6 +107,8 @@ export const InputbarCore: FC<InputbarCoreProps> = ({
   textareaRef,
   resizeTextArea,
   focusTextarea,
+  height,
+  onHeightChange,
   supportedExts,
   isLoading,
   onPause,
@@ -131,8 +136,6 @@ export const InputbarCore: FC<InputbarCoreProps> = ({
   } = useSettings()
   const quickPanelTriggersEnabled = forceEnableQuickPanelTriggers ?? enableQuickPanelTriggers
 
-  const [textareaHeight, setTextareaHeight] = useState<number>()
-
   const { t } = useTranslation()
   const [isTranslating, setIsTranslating] = useState(false)
   const { getLanguageByLangcode } = useTranslate()
@@ -538,8 +541,8 @@ export const InputbarCore: FC<InputbarCoreProps> = ({
 
       const handleMouseMove = (e: MouseEvent) => {
         const deltaY = startDragY.current - e.clientY
-        const newHeight = Math.max(40, Math.min(400, startHeight.current + deltaY))
-        setTextareaHeight(newHeight)
+        const newHeight = Math.max(40, Math.min(500, startHeight.current + deltaY))
+        onHeightChange(newHeight)
       }
 
       const handleMouseUp = () => {
@@ -550,7 +553,7 @@ export const InputbarCore: FC<InputbarCoreProps> = ({
       document.addEventListener('mousemove', handleMouseMove)
       document.addEventListener('mouseup', handleMouseUp)
     },
-    [config.enableDragDrop, setTextareaHeight, textareaRef]
+    [config.enableDragDrop, onHeightChange, textareaRef]
   )
 
   const onQuote = useCallback(
@@ -667,11 +670,11 @@ export const InputbarCore: FC<InputbarCoreProps> = ({
             variant="borderless"
             spellCheck={enableSpellCheck}
             rows={2}
-            autoSize={textareaHeight ? false : { minRows: 2, maxRows: 20 }}
+            autoSize={height ? false : { minRows: 2, maxRows: 20 }}
             styles={{ textarea: TextareaStyle }}
             style={{
               fontSize,
-              height: textareaHeight,
+              height: height,
               minHeight: '30px'
             }}
             disabled={isTranslating || searching}