Ran up fee for detail (7)
I believe the answer is:
narrate
'detail' is the definition.
(thesaurus)
'ran up fee' is the wordplay.
'up' says the letters should be written in reverse (in down clue: letters go upwards).
'fee' becomes 'rate' (I've seen this in other clues).
'ran' back-to-front is 'nar'.
'nar'+'rate'='NARRATE'
'for' acts as a link.
(Other definitions for narrate that I've seen before include "rehearse" , "Report; tell" , "Tell story,recount" , "Give (film) commentary" , "Rare ant (anag.)" .)