Would an Artificer's steel defender stop working if it stepped in antimagic field?
— SEL | hmd (@manil_hmd) April 20, 2020
An artificer's steel defender isn't a spell, a magic item, or an effect labeled as magical by a rule. It is therefore not affected by the antimagic field spell. #DnD https://t.co/35z6arRwmO
— Jeremy Crawford (@JeremyECrawford) April 20, 2020
Conceptually yes, an antimagic field should suppress whatever magic power is animating any magical construct. 5e's rules on what is considered magical are entirely arbitrary and oftentimes nonsensical.
— Gilded (@GiIded) April 20, 2020
In D&D, some things are created/altered by magic but then endure without it. Your wound closes thanks to a spell, but thereafter the wound stays closed on its own and can’t be dispelled. Similarly, magic can turn a corpse into a zombie, which then needs no magic to endure. #DnD https://t.co/F2xTYITwj4
— Jeremy Crawford (@JeremyECrawford) April 20, 2020