Manuscript about assistance provided by servants (5)
I believe the answer is:
maids
'servants' is the definition.
(maid is a kind of servant)
'manuscript about assistance' is the wordplay.
'manuscript' becomes 'ms' (abbreviation for manuscript).
'about' indicates putting letters inside.
'assistance' becomes 'aid' (synonyms).
'ms' going around 'aid' is 'MAIDS'.
'provided by' acts as a link.
(Other definitions for maids that I've seen before include "Getting women in service" , "girls!" , "Female domestic servants" , "Lasses" , "Female domestics" .)