Leveled my Artificer to level 3 and chose Battle Smith. Under Tools of the Trade of the Trade it says, "Tool Proficiency. You gain proficiency with Smith’s Tools. If you already have this proficiency, you gain proficiency with one other type of Artisan’s Tools of your choice." Since i already had proficiency in Smith's Tools i selected "Choose an Artisan's Tool", which turns out to be not very useful as it doesn't then give me the option to select any Tools, but the character editor just considers everything to be finished anyway.
Leveled my Artificer to level 3 and chose Battle Smith. Under Tools of the Trade of the Trade it says, "Tool Proficiency. You gain proficiency with Smith’s Tools. If you already have this proficiency, you gain proficiency with one other type of Artisan’s Tools of your choice." Since i already had proficiency in Smith's Tools i selected "Choose an Artisan's Tool", which turns out to be not very useful as it doesn't then give me the option to select any Tools, but the character editor just considers everything to be finished anyway.
My personal workaround was that i'd originally chosen Smith's Tools as part of the Artisan background, so i went and edited that tool selection.