There's a scripting guide and scripting reference that come with the server -- they're a little different than the desktop version... unfortunately the guide isn't quite different enough, so there's also 'trial and error'. :(
Alert, confirm, etc... Adobe InDesign Server will supress these.
Unfortunately they don't show up in the errorList so you don't have access to the supressed messages. If you do want the message to show up in the server console and to be available in the error list you can use these: