Run a racket an agent set up (7)
I believe the answer is:
scamper
'run' is the definition.
(I know that scamper is a more specific form of the action run)
'a racket an agent set up' is the wordplay.
'a racket' becomes 'scam' (racket is a type of scam or scheme).
'an agent' becomes 'rep' (short for representative).
'set up' says the letters should be written backwards (in a down clue, letters go up).
'rep' back-to-front is 'per'.
'scam'+'per'='SCAMPER'
(Other definitions for scamper that I've seen before include "Skip around" , "Run around" , "Proceed hurriedly" , "Run with quick light steps" , "Skip playfully with campers" .)