How could I export class information and turn it into a syntax helper from a closed application?

I'm coding in an application that has built in editor and the module only available for internal use, so it doesn't allow me to reference it in Visual Studio and code outside its environment.

What would be the best way to export that class information from within to a documentation which I could then just import into VS and use as syntax helper?

I thought of using reflection and write it in xml, is there any better way?