Agreed to be restricted about everything (7)
I believe the answer is:
tallied
'agreed' is the definition.
('tally' can be a synonym of 'agree')
'restricted about everything' is the wordplay.
'restricted' becomes 'tied' (tying is a kind of restricting).
'about' means one lot of letters goes inside another.
'everything' becomes 'all' (all things).
'tied' enclosing 'all' is 'TALLIED'.
'to be' is the link.
(Other definitions for tallied that I've seen before include "Reckoned debt or score" , "Agreed; calculated" , "Matched" , "Agreed, corresponded" , "Corresponded - kept score" .)