How to tell housekeeper to not bring her children to my house

We have a housekeeper that has been with us for 3 years. She comes twice a week for 3 hours and does the same tasks every time. She’s great and we really rely on her. She barely calls out and sometimes adjusts the days she can come and we fully accommodate her schedule. She can be in the house without us, and we fully trust her.

On the other hand, she has 4 kids (7f,8m,14f,15m), and she brings at least 2 if not all the kids at least once a week to our house. She used to bring them over the summer and say that she has to bring them because they’re not in school, which we accommodated.

However, summer has been over for a while now and they are continuously over. She does not tell us when she will be bringing them. She shows up with them. They are not quiet and calm kids. The younger two are running in and out of the house, up and down the stairs, going in all the rooms and closets, playing with my kids toys and not putting them back. The older two are hiding somewhere in our house. I found one laying on the floor of a guest bedroom once. Their mom (our housekeeper ) doesn’t say anything to them and just does her tasks.

I have two daughters of my own and they truly enjoy playing with her kids, but when it’s time to eat, I have to feed all her kids too. They ask for food and I cannot say no to kids. I had offered them to help themselves to snacks over the summer since I thought it was a short term thing, but we are going through a lot of snacks now that they are grabbing multiple snacks and drinks. My kids are younger than hers, and they really do what these older kids do and some of it is not safe.

Furthermore, she has some of her older kids do the housework and it’s not done to my liking— things are out of order and unfinished and this defeats the purpose of having her come over. I am too hesitant to say anything , because I don’t want to lose her, but how do I communicate with her that her kids do not need to be coming with her …

To clarify: I work PT out of the house and she can come any hours that suit her. I am extremely irritated when I come home while she’s there working, and I unknowingly run into her kids in my house after a long day in the office.. and have to deal with my own kids and their after school routine.. it throws everything off..

Thank you everyone for your suggestions. I think being upfront in a kind way is the best option. Let’s see when I will have the courage to do so..