diff --git a/api/azureai_client.py b/api/azureai_client.py
index 948e86c30..5d70e5cee 100644
--- a/api/azureai_client.py
+++ b/api/azureai_client.py
@@ -75,6 +75,12 @@
 def get_first_message_content(completion: ChatCompletion) -> str:
     r"""When we only need the content of the first message.
     It is the default parser for chat completion."""
+    if (
+        not completion.choices
+        or completion.choices[0].message is None
+        or completion.choices[0].message.content is None
+    ):
+        raise ValueError("LLM returned empty or filtered response")
     return completion.choices[0].message.content
 
 
diff --git a/api/openai_client.py b/api/openai_client.py
index bc75ed586..afa4059ad 100644
--- a/api/openai_client.py
+++ b/api/openai_client.py
@@ -59,6 +59,12 @@ def get_first_message_content(completion: ChatCompletion) -> str:
     r"""When we only need the content of the first message.
     It is the default parser for chat completion."""
     log.debug(f"raw completion: {completion}")
+    if (
+        not completion.choices
+        or completion.choices[0].message is None
+        or completion.choices[0].message.content is None
+    ):
+        raise ValueError("LLM returned empty or filtered response")
     return completion.choices[0].message.content