As per your version you seem to be in HR department. Even if you are not in HR it is always advisable for drafting yourself a copy of the agreement and seek suggestions to the forum.
Seniors are always there to help you.
But also check out one thing, you are stating a labour supply agreement and other side you are stating their services to be in quality,machine operation etc, which become core functions.
Please take necessary steps to ensure (check for the license of Labour supplier) it is a valid agreement which is being entered into.
19th July 2018 From India, Hyderabad