Get Treaty Six to provide a way to end the agreement (4,8)
I believe the answer is:
exit strategy
'a way to end the agreement' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'get treaty six to provide' is the wordplay.
'to provide' is an anagram indicator.
'get'+'treaty'+'six'='gettreatysix'
'gettreatysix' with letters rearranged gives 'EXIT STRATEGY'.
Can you help me to learn more?
(Other definitions for exit strategy that I've seen before include "Plan for future disengagement from a commitment" , "Plan to get out!" , "Withdrawal plan" , "Plan to go" .)