Etymonline.com gives a lot of definitions regarding an implement or instrument, specifically inanimate objects.
But the word has crept into English slang in reference to people, as in "he is a total tool." Would this mean that he is someone's "puppet?" Or if someone said, "He is a tool of IBM," would this mean that he was a (blindly loyal) company man? Could this refer to a kind of soldier (e.g. a Japanese during World War II) who would jump off a cliff if ordered to do so by an officer?