diff --git a/web/pages/Assistants.tsx b/web/pages/Assistants.tsx
index 9c9be45..10cbb44 100644
--- a/web/pages/Assistants.tsx
+++ b/web/pages/Assistants.tsx
@@ -1275,10 +1275,13 @@ export const DebugDrawer: React.FC<{
   const handleTextLaunch = async () => {
     try {
       setWsError('');
+      // Start every text debug run as a fresh session transcript.
+      setMessages([]);
+      assistantDraftIndexRef.current = null;
       if (textTtsEnabled) await ensureAudioContext();
       await ensureWsSession();
       setTextSessionStarted(true);
-      setMessages((prev) => (prev.length > 0 ? prev : [{ role: 'model', text: assistant.opener || 'Hello!' }]));
+      setMessages([{ role: 'model', text: assistant.opener || 'Hello!' }]);
     } catch (e) {
       console.error(e);
       setWsStatus('error');
@@ -1801,7 +1804,7 @@ export const DebugDrawer: React.FC<{
             </div>
 
             <div className="shrink-0 space-y-2">
-              <div className="flex space-x-2">
+              <div className="flex items-center gap-2 min-w-0">
                 {mode === 'text' && textSessionStarted && (
                   <Button variant="destructive" size="sm" className="h-9 font-bold shrink-0" onClick={closeWs}>
                     <PhoneOff className="mr-2 h-4 w-4" /> 结束测试
@@ -1813,9 +1816,9 @@ export const DebugDrawer: React.FC<{
                   placeholder={mode === 'text' && !textSessionStarted ? "请先发起呼叫后输入消息..." : (mode === 'text' ? "输入消息..." : "输入文本模拟交互...")}
                   onKeyDown={e => e.key === 'Enter' && handleSend()}
                   disabled={isLoading || (mode === 'text' ? !textSessionStarted : callStatus !== 'active')}
-                  className="flex-1"
+                  className="flex-1 min-w-0"
                 />
-                <Button size="icon" onClick={handleSend} disabled={isLoading || (mode === 'text' ? !textSessionStarted : callStatus !== 'active')}><Send className="h-4 w-4" /></Button>
+                <Button size="icon" className="shrink-0" onClick={handleSend} disabled={isLoading || (mode === 'text' ? !textSessionStarted : callStatus !== 'active')}><Send className="h-4 w-4" /></Button>
               </div>
             </div>
         </div>