Update app.py

app.py

@@ -63,7 +63,7 @@ for msg in st.session_state.messages:
 
 if prompt := st.chat_input("Message..."):
     if not api_key:
-        st.error("API key required")
+        st.error("API key required! Please create one at https://dashboard.cohere.com/")
         st.stop()
     st.session_state.first_message_sent = True
     st.session_state.messages.append({"role": "user", "content": prompt})