Agree in advance to briefly get ready to put a stop to quarry (12)
I believe the answer is:
predetermine
'agree in advance to briefly get ready' is the definition.
I can't tell whether this defines the answer.
'put a stop to quarry' is the wordplay.
'put' becomes 'pre' (I can't justify this - if you can you should give a lot more credence to this answer).
'a stop' becomes 'deter' (I've seen this before).
'to quarry' becomes 'mine'.
'pre'+'deter'+'mine'='PREDETERMINE'
'to' is the link.
Can you help me to learn more?
(Another definition for predetermine that I've seen is " Decide in advance".)