In the loop, newly employed fellow minder (4-8)
'in the loop' is the definition.
(someone in the loop is well-informed)
'newly employed fellow minder' is the wordplay.
'newly employed' indicates anagramming the letters (letters used or employed in a new way).
'fellowminder' with letters rearranged gives 'WELL-INFORMED'.
(Another definition for well-informed that I've seen is "Knowing the latest".)