diff --git a/engine/core/duplex_pipeline.py b/engine/core/duplex_pipeline.py
index 06052b0..44d3cad 100644
--- a/engine/core/duplex_pipeline.py
+++ b/engine/core/duplex_pipeline.py
@@ -73,6 +73,7 @@ class DuplexPipeline:
     _ASR_DELTA_THROTTLE_MS = 500
     _LLM_DELTA_THROTTLE_MS = 80
     _ASR_CAPTURE_MAX_MS = 15000
+    _OPENER_PRE_ROLL_MS = 180
     _DEFAULT_TOOL_SCHEMAS: Dict[str, Dict[str, Any]] = {
         "current_time": {
             "name": "current_time",
@@ -781,6 +782,9 @@ class DuplexPipeline:
         )
         await self.conversation.add_assistant_turn(greeting_to_speak)
 
+        # Give client mic capture a short head start so opener can be interrupted immediately.
+        await asyncio.sleep(self._OPENER_PRE_ROLL_MS / 1000.0)
+
         used_preloaded_audio = await self._play_preloaded_opener_audio()
         if self._tts_output_enabled() and not used_preloaded_audio:
             # Keep opener text ahead of opener voice start.
diff --git a/web/pages/Assistants.tsx b/web/pages/Assistants.tsx
index e8af420..cb79bfd 100644
--- a/web/pages/Assistants.tsx
+++ b/web/pages/Assistants.tsx
@@ -178,7 +178,7 @@ export const AssistantsPage: React.FC = () => {
       hotwords: [],
       tools: [],
       botCannotBeInterrupted: false,
-      interruptionSensitivity: 500,
+      interruptionSensitivity: 180,
       configMode: 'platform',
     };
     try {
@@ -1049,7 +1049,7 @@ export const AssistantsPage: React.FC = () => {
                                                 <div className="relative">
                                                     <Input 
                                                         type="number"
-                                                        value={selectedAssistant.interruptionSensitivity || 500}
+                                                        value={selectedAssistant.interruptionSensitivity || 180}
                                                         onChange={(e) => updateAssistant('interruptionSensitivity', parseInt(e.target.value) || 0)}
                                                         className="w-20 h-8 text-right pr-7 text-xs font-mono bg-black/40 border-white/5"
                                                     />
@@ -1063,7 +1063,7 @@ export const AssistantsPage: React.FC = () => {
                                                 min="0" 
                                                 max="2000" 
                                                 step="50" 
-                                                value={selectedAssistant.interruptionSensitivity || 500}
+                                                value={selectedAssistant.interruptionSensitivity || 180}
                                                 onChange={(e) => updateAssistant('interruptionSensitivity', parseInt(e.target.value))}
                                                 className="flex-1 h-1.5 bg-secondary rounded-lg appearance-none cursor-pointer accent-primary"
                                             />
@@ -2075,13 +2075,14 @@ export const DebugDrawer: React.FC<{
         setWsError('');
         setDynamicVariablesError('');
         closeWs();
-      if (textTtsEnabled) await ensureAudioContext();
-      await ensureWsSession();
-      await startVoiceCapture();
-      setCallStatus('active');
-    } catch (e) {
-      console.error(e);
-      stopVoiceCapture();
+        if (textTtsEnabled) await ensureAudioContext();
+        // Start mic capture before session.start so barge-in works from opener start.
+        await startVoiceCapture();
+        await ensureWsSession();
+        setCallStatus('active');
+      } catch (e) {
+        console.error(e);
+        stopVoiceCapture();
         setCallStatus('idle');
         const err = e as Error & { __dynamicVariables?: boolean };
         if (err.__dynamicVariables) {
@@ -2378,7 +2379,7 @@ export const DebugDrawer: React.FC<{
         generatedOpenerEnabled: assistant.generatedOpenerEnabled === true,
         bargeIn: {
           enabled: assistant.botCannotBeInterrupted !== true,
-          minDurationMs: assistant.interruptionSensitivity || 500,
+          minDurationMs: Math.max(0, Number(assistant.interruptionSensitivity ?? 180)),
         },
         knowledgeBaseId,
         knowledge,