Haggle for a year to get the agreement (6)
I believe the answer is:
treaty
'the agreement' is the definition.
(treaty is a kind of agreement)
'haggle for a year' is the wordplay.
I cannot really see how this works, but
'a' is found in the answer.
'year' could be 'y' and 'y' is found within the answer.
The remaining letters 'tret' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'to get' acts as a link.
Can you help me to learn more?
(Other definitions for treaty that I've seen before include "Formal agreement between states" , "Political or private agreement" , "Formal pact" , "A pact between countries" , "Covenant" .)