After a month agent has modern technology falling apart (8)
I believe the answer is:
decrepit
'falling apart' is the definition.
(I've seen this in another clue)
'after a month agent has modern technology' is the wordplay.
'after' says to put letters next to each other.
'a month' becomes 'dec' (abbreviation for December).
'agent' becomes 'rep' (short for representative).
'has' says to put letters next to each other.
'modern technology' becomes 'it' (Information Technology).
'dec' next to 'rep' is 'decrep'.
'decrep'+'it'='DECREPIT'
(Other definitions for decrepit that I've seen before include "Getting on" , "Cited rep for being old and dilapidated" , "Worn out by age or use" , "Elderly, infirm" , "rickety" .)