He's in automation (3)
I believe the answer is:
tom
'he's' is the definition.
(I've seen this in another clue)
'in automation' is the wordplay.
'in' says the answer is hidden in the clue.
'TOM' is hidden within 'automation'.
(Other definitions for tom that I've seen before include "What Dick Whittington had" , "type pursuing queen" , "Queen's mate" , "Boy running off with pig" , "Pig-stealing piper's son" .)