diff --git a/backend/onyx/agent_search/pro_search_a/answer_initial_sub_question/nodes/answer_check.py b/backend/onyx/agent_search/pro_search_a/answer_initial_sub_question/nodes/answer_check.py
index 2d8e8c4d168..ac4ceb2ef7e 100644
--- a/backend/onyx/agent_search/pro_search_a/answer_initial_sub_question/nodes/answer_check.py
+++ b/backend/onyx/agent_search/pro_search_a/answer_initial_sub_question/nodes/answer_check.py
@@ -7,10 +7,16 @@
 from onyx.agent_search.pro_search_a.answer_initial_sub_question.states import (
     QACheckUpdate,
 )
+from onyx.agent_search.shared_graph_utils.prompts import SUB_CHECK_NO
 from onyx.agent_search.shared_graph_utils.prompts import SUB_CHECK_PROMPT
+from onyx.agent_search.shared_graph_utils.prompts import UNKNOWN_ANSWER
 
 
 def answer_check(state: AnswerQuestionState) -> QACheckUpdate:
+    if state["answer"] == UNKNOWN_ANSWER:
+        return QACheckUpdate(
+            answer_quality=SUB_CHECK_NO,
+        )
     msg = [
         HumanMessage(
             content=SUB_CHECK_PROMPT.format(
diff --git a/backend/onyx/agent_search/shared_graph_utils/prompts.py b/backend/onyx/agent_search/shared_graph_utils/prompts.py
index 6ee3cbe21b3..18c8092ce00 100644
--- a/backend/onyx/agent_search/shared_graph_utils/prompts.py
+++ b/backend/onyx/agent_search/shared_graph_utils/prompts.py
@@ -79,8 +79,11 @@
     """
 )
 
+SUB_CHECK_YES = "yes"
+SUB_CHECK_NO = "no"
 
-SUB_CHECK_PROMPT = """
+SUB_CHECK_PROMPT = (
+    """
     Your task is to see whether a given answer addresses a given question.
     Please do not use any internal knowledge you may have - just focus on whether the answer
     as given seems to largely address the question as given, or at least addresses part of the question.
@@ -92,7 +95,9 @@
     \n ------- \n
     {base_answer}
     \n ------- \n
-    Does the suggested answer address the question? Please answer with yes or no:"""
+    Does the suggested answer address the question? Please answer with """
+    + f'"{SUB_CHECK_YES}" or "{SUB_CHECK_NO}".'
+)
 
 
 BASE_CHECK_PROMPT = """ \n