diff --git a/libs/langchain/langchain/chains/router/multi_prompt_prompt.py b/libs/langchain/langchain/chains/router/multi_prompt_prompt.py
index ac48f558830..5221ea9334d 100644
--- a/libs/langchain/langchain/chains/router/multi_prompt_prompt.py
+++ b/libs/langchain/langchain/chains/router/multi_prompt_prompt.py
@@ -27,5 +27,5 @@ modifications are needed.
 << INPUT >>
 {{input}}
 
-<< OUTPUT >>
+<< OUTPUT (must include ```json at the start of the response) >>
 """