It's more agreeable back in the precinct (5)
I believe the answer is:
nicer
'it's more agreeable' is the definition.
(nice can mean agreeable)
'back in the precinct' is the wordplay.
'back' says the letters should be written in reverse.
'in' says the answer is hidden in the clue.
'recin' can be found hidden inside 'precinct'.
'recin' in reverse letter order is 'NICER'.
(Other definitions for nicer that I've seen before include "Pleasanter" , "more accurate" , "harder to please" , "More pleasant or fine" , "improved" .)