> running oxfmt without any arguments recursively scans directory tree from the current directory for all .js and .ts files and silently reformats them

I've got to say this is what I would have expected and wanted to happen. I'd say it is wise to not run tools designed to edit files on files you don't have a backup for (like Git) without doing a dry-run or a small scope experiment first.

While I can get behind things such as "use version control," "use backups", etc. this is definitely not what I'd expect from a program run without arguments, especially when it will go and change stuff.