Short novel acquired by agent (6)
I believe the answer is:
skimpy
'short' is the definition.
(thesaurus)
'novel acquired by agent' is the wordplay.
'novel' becomes 'kim' (Rudyard Kipling novel).
'acquired by' indicates putting letters inside.
'agent' becomes 'spy' (spy is a kind of agent).
'kim' put inside 'spy' is 'SKIMPY'.
(Other definitions for skimpy that I've seen before include "Scanty (clothing)" , "Scanty or mean" , "'Scanty, barely enough (6)'" , "Meagre; (of clothes) short and revealing" , "Inadequate (of clothing)" .)