diff --git a/packages/services/voice-agent/src/agent.py b/packages/services/voice-agent/src/agent.py
index b0b98a1..cd63239 100644
--- a/packages/services/voice-agent/src/agent.py
+++ b/packages/services/voice-agent/src/agent.py
@@ -227,7 +227,7 @@ async def entrypoint(ctx: JobContext) -> None:
         _http_client_tts = _httpx.AsyncClient(verify=False)
         _oai_client_tts = _openai.AsyncOpenAI(http_client=_http_client_tts)
 
-        default_instructions = "用自然、友好的中文语气说话，语速适中，像真人助手一样。"
+        default_instructions = "用自然、友好的中文语气说话，语速稍快，简洁干练，像专业助手一样。"
         tts = openai_plugin.TTS(
             model=settings.openai_tts_model,
             voice=tts_voice,