Demand to be accurate (5)
I believe the answer is:
exact
I believe this clue is a double definition.
'demand' is the first definition.
(exacting is a kind of demanding)
'accurate' is the second definition.
('exact' can be a synonym of 'accurate')
'to be' acts as a link.
(Other definitions for exact that I've seen before include "Rigorous" , "19 [WREST]" , "on the money" , "totally accurate" , "Meticulous" .)