diff --git a/.env.local.example b/.env.local.example
index 992bfab..1c0936e 100644
--- a/.env.local.example
+++ b/.env.local.example
@@ -1,2 +1,3 @@
-OPENAI_API_KEY=YOUR_KEY
-DEFAULT_MODEL=gpt-3.5-turbo
\ No newline at end of file
+DEFAULT_MODEL=gpt-3.5-turbo
+DEFAULT_SYSTEM_PROMPT=CUSTOM_SYSTEM_PROMPT
+OPENAI_API_KEY=YOUR_KEY
\ No newline at end of file
diff --git a/utils/app/const.ts b/utils/app/const.ts
index 3d01428..4155a3e 100644
--- a/utils/app/const.ts
+++ b/utils/app/const.ts
@@ -1,5 +1,5 @@
 export const DEFAULT_SYSTEM_PROMPT =
-  "You are ChatGPT, a large language model trained by OpenAI. Follow the user's instructions carefully. Respond using markdown.";
+  process.env.DEFAULT_SYSTEM_PROMPT || "You are ChatGPT, a large language model trained by OpenAI. Follow the user's instructions carefully. Respond using markdown.";
 
 export const OPENAI_API_HOST =
   process.env.OPENAI_API_HOST || 'https://api.openai.com';