Automaton, companion making a hash of things (5)
I believe the answer is:
botch
'a hash of things' is the definition.
'automaton companion' is the wordplay.
'automaton' becomes 'bot'.
'companion' becomes 'ch' (I've seen this in other clues).
'bot'+'ch'='BOTCH'
'making' is the link.
(Other definitions for botch that I've seen before include "Repair badly" , "Mend clumsily" , "bad job" , "mistake" , "Spoil by clumsy workmanship" .)