diff --git a/packages/services/voice-agent/src/agent.py b/packages/services/voice-agent/src/agent.py
index 4fce32e..3f04de2 100644
--- a/packages/services/voice-agent/src/agent.py
+++ b/packages/services/voice-agent/src/agent.py
@@ -137,10 +137,17 @@ async def entrypoint(ctx: JobContext) -> None:
     # Build STT
     if settings.stt_provider == "openai":
         from livekit.plugins import openai as openai_plugin
+        import httpx as _httpx
+        import openai as _openai
+
+        # OPENAI_BASE_URL may use a self-signed certificate (e.g. proxy)
+        _http_client = _httpx.AsyncClient(verify=False)
+        _oai_client = _openai.AsyncOpenAI(http_client=_http_client)
 
         stt = openai_plugin.STT(
             model=settings.openai_stt_model,
             language=settings.whisper_language,
+            client=_oai_client,
         )
     else:
         stt = LocalWhisperSTT(
@@ -151,10 +158,16 @@ async def entrypoint(ctx: JobContext) -> None:
     # Build TTS
     if settings.tts_provider == "openai":
         from livekit.plugins import openai as openai_plugin
+        import httpx as _httpx
+        import openai as _openai
+
+        _http_client_tts = _httpx.AsyncClient(verify=False)
+        _oai_client_tts = _openai.AsyncOpenAI(http_client=_http_client_tts)
 
         tts = openai_plugin.TTS(
             model=settings.openai_tts_model,
             voice=settings.openai_tts_voice,
+            client=_oai_client_tts,
         )
     else:
         tts = LocalKokoroTTS(
diff --git a/packages/services/voice-agent/src/plugins/agent_llm.py b/packages/services/voice-agent/src/plugins/agent_llm.py
index cec7f92..a600068 100644
--- a/packages/services/voice-agent/src/plugins/agent_llm.py
+++ b/packages/services/voice-agent/src/plugins/agent_llm.py
@@ -100,6 +100,16 @@ class AgentServiceLLMStream(llm.LLMStream):
                 user_text = item.text_content
                 break
 
+        if not user_text:
+            # on_enter/generate_reply may call LLM without a user message;
+            # look for the developer/system instruction to use as prompt
+            for item in self._chat_ctx.items:
+                if getattr(item, "type", None) != "message":
+                    continue
+                if item.role in ("developer", "system"):
+                    user_text = item.text_content
+                    break
+
         if not user_text:
             logger.warning("No user message found in chat context")
             return