Can I lock a tool or folder to guard against mistakenly changing something?

Yes, you can lock a folder or a tool by clicking on the open-lock icon to the right of each folder or tool. If you lock a folder, all the tools in that folder will be locked, also. If you attempt to alter an input value in a locked tool, a closed-lock icon will flash in the input box to remind you it is locked. In order to unlock a folder or tool, click on the closed-lock icon.