Creating files and folders is not an async operation (of course unless you invoke them async). This means, once a new file/folder had been created it should be pretty straightforward to add any bool to the output, since GH only continues until the folder had been created . So assuming you created a new Output Parameter called „A“ you can assign a true to within the conditional branch and for any other a false.
You can also track behavior of files and directories by using the FileWatcher class and subscribing to its events. But I can only repeat the following on and on. Prevent creating async behavior from scripts and Gh definitions, and if you do keep it within the scope of execution. Scripts are meant to be linear, Gh definitions as well.