diff --git a/service/.env b/service/.env
index f43cd03..e3b0692 100644
--- a/service/.env
+++ b/service/.env
@@ -1,2 +1,3 @@
-# OpenAI API Key
-OPENAI_API_KEY=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
+# OpenAI API Key - https://platform.openai.com/overview
+# e.g: This key is invalid
+OPENAI_API_KEY='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'