Update app.py

app.py

@@ -131,6 +131,17 @@ Examples:
 - For "show me purchase orders": CALL_TOOL: get_purchase_orders
 - For "get 20 purchase orders": CALL_TOOL: get_purchase_orders(top=20)
 - For "latest tech news": CALL_TOOL: get_news_headlines(category=technology)
+- For "get news from BBC": CALL_TOOL: get_news_by_source(source_id=bbc-news)
+- For "get news from CNN": CALL_TOOL: get_news_by_source(source_id=cnn)
+- For "get news from Reuters": CALL_TOOL: get_news_by_source(source_id=reuters)
+
+IMPORTANT: For news by source queries, always include the source_id parameter:
+- BBC: source_id=bbc-news
+- CNN: source_id=cnn  
+- Reuters: source_id=reuters
+- Associated Press: source_id=associated-press
+- The Guardian: source_id=the-guardian
+- Washington Post: source_id=the-washington-post
 
 After calling a tool, I will provide you with the results to interpret for the user.
 """