SMT takes optional arguments before build targets. Note that if a folder doesn't exist, SMT will stop the entire build operation and clean up the mod folder in the specified Starbound root directory Arguments SMT interprets and builds each folder from left to right. This can also be run with multiple folders. In that case, define the names of the folders in your current directory and run SMT. Obviously, you may not want to be using the testing folder every time you want to test mods. This causes SMT to use the folder named testing in the directory SMT is in, builds a mod based on that, and runs Starbound. Starbound Mod Tester (or SMT, as I will be calling it from now on) can be run with absolutely no arguments, as follows: Starbound Mod Tester is a simple, portable and effective way for Starbound mod developers to make quick changes to mods and easily test them out, and also a utility with non-development uses.