I make a file named: app/models/active_storage/attachment.rb. Because it's in your project it takes loading precedence over the Gem version. Then inside we load the Gem version, and then monkeypatch it using class_eval: active_storage_gem_path = Gem::Specification.find_by_name('activestorage').gem_dir require "#{active_storage_gem_path}/app/models/active_storage/attachment" ActiveStorage::Attachment.class_eval do acts_as_taggable on: :tags end The slightly nasty part is locating the original file, since we can't find it normally because our new file takes precedence. This is not necessary in production, so you could put a if Rails.env.production? around it if you like I think.

This leads to an override of the controller as well

Create a new controller to override the original: app/controllers/active_storage/blobs_controller.rb

you can define locally parse and it should take precedence over the one in the library: interface JSON { parse(text: string, reviver?: (key: any, value: any) => any): unknown; }

As was mentioned in the comments above, the material design spec for buttons specifies that the text should be uppercase, but you can easily override its CSS property: paper-button { text-transform: none; }

@use "@material/theme" with (  $primary: #FEDBD0,  $on-primary: #442C2E);

By default, fetch() doesn’t provide a way to intercept requests, but it’s not hard to come up with a workaround. You can overwrite the global fetch method and define your own interceptor, like this

If you're given a set of factories (say, from a gem developer) but want to change them to fit into your application better, you can modify that factory instead of creating a child factory and adding attributes there.