Adding Run Script build phase ouptut files to target

We have an Aggregate target with a custom Run Script build phase that consumes a JSON file in the project and outputs a .swift file and an .xcassets folder. However, getting our primary app target to see and include these output files has required some hacky measures (that I'd rather not delve into), and I'm wondering if there's something I'm missing.

What's the defacto way of ensuring that Build Phase output files get included as sources file in an app build?