workaround for paperqa requiring global apikey

app.py

@@ -59,7 +59,6 @@ tool_list.columns = ['Tool', 'Description']
 
 def on_api_key_change():
     api_key = ss.get('api_key') or os.getenv('OPENAI_API_KEY')
-    os.environ['OPENAI_API_KEY'] = ss.get('api_key')
     # Check if key is valid
     if not oai_key_isvalid(api_key):
         st.write("Please input a valid OpenAI API key.")
@@ -148,4 +147,9 @@ with st.sidebar:
 
 # Execute agent on user input
 if user_input := st.chat_input():
+    if ss.get('api_key') is not None:
+        os.environ['OPENAI_API_KEY'] = ss.get('api_key')
+
     run_prompt(user_input)
+    os.environ['OPENAI_API_KEY'] = 'none'
+