A job to do — to ask if nothing's missing (4)
I believe the answer is:
task
'a job to do' is the definition.
(I've seen this in another clue)
'to ask if nothing's missing' is the wordplay.
I cannot really see how this works, but
'to ask' could be 'ask' and 'ask' is located in the answer.
A single letter 't' remains which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for task that I've seen before include "Chore, job." , "Difficult piece of work" , "Give mission" , "Piece of work to be done" , "Job to be done" .)