Works a treat, reversing to include charge (4)
I believe the answer is:
task
'charge' is the definition.
(thesaurus)
'works a treat reversing to include' is the wordplay.
'to include' indicates the answer is hidden within the clue.
'reversing' says the letters should be written backwards.
'ksat' can be found hidden inside 'works a treat'.
'ksat' written backwards gives 'TASK'.
(Other definitions for task that I've seen before include "Job, undertaking" , "Chore, job." , "Burden with work" , "Arduous bit of work" , "exercise" .)