Why can't the Oracle action use a built-in script?
 

VBP has a script editor built in, but I can't seem to use it on the Oracle action. Instead, I need to have an external file that it calls. Is there anything magic I can type in the "Script File" parameter to get it to use a script I create with the script editor?

It has to be an external file, but you could use a Write File action before the Oracle step to create the file (i.e., at %TEMP%\xyz.sql), editing the script in the Write File action's editor (which will use syntax coloring for supported file extensions), and then run that script.