Valid claim you have to being perfect (4,5)
I believe the answer is:
just right
'to being perfect' is the definition.
(I've seen this before)
'valid claim' is the wordplay.
'valid' becomes 'just' (I can't explain this - if you can you should give a lot more credence to this answer).
'claim' becomes 'right' (I've seen this before).
'just'+'right'='JUST RIGHT'
'you have' is the link.
This may not be right. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for just right that I've seen before include "Perfect" , "Exactly what was required" .)