I  have added a tool in galaxy. After clicking 'Execute',  this tool will query an external database for some information to ensure that there are no conflict records in the database. So sometimes an alert message should be sent to user if there are wrong records in the database. But I have not found out an efficient way to implement this in galaxy.  I am wondering if it is possible to give some warning message to users when running a tool in galaxy and how to do it if it is feasible.

I implemented the tool with an xml file and a python file. I am wondering calling javascript from the python code to give user error information. But it seems infeasible and I do not know where to start.

Do you have any ideas? 

Thank you very much!

Best regards,

--Bingxin