Note in brief I've recorded (5)
I believe the answer is:
fiver
'note' is the definition.
(I know that fiver is a type of note)
'in brief i've recorded' is the wordplay.
'in' indicates the answer is hidden within the clue.
'FIVER' can be found hidden inside 'brief ive recorded'.
(Other definitions for fiver that I've seen before include "Smallest English note" , "money" , "Banknote (informal)" , "Bank note" , "Half a tenner" .)