Foster parents are responsible for looking after the health and well-being of children placed in your care. This includes such things as obtaining appropriate medical and dental care, providing nourishing, well-balanced meals, enrolling the child in school, taking an active interest in his schoolwork and social activities, and providing adequate clothing and other essentials. These responsibilities are similar to those of all parents.
With a foster child, however, there are two additional responsibilities. One is to freely share information about the child with the child's social worker, and the other is to cooperate fully with the case plan established for the child and his family.
As a foster parent, you enter into a "co-parenting" agreement, that is, you agree that you and others (e.g. agency representatives and county) will be "parenting" the child. In a way, your home becomes an extension of the foster family agency. Any actions committed by the foster parent is attributed to the foster family agency. For example, a foster parent does not close the door at night and the child runs away.
Even in cases where it is known that the child has a history of running, the above scenario may be labeled as "inappropriate supervision by foster parent, resulting in child running away". If the allegation is found to be "substantiated", the agency is cited. Notice that the agency is cited for actions of the foster parent.
That is why high quality and elite foster family agencies will do everything everything to ensure that foster parents are supported at all times and have the necessary skills and resources to ensure that children are safe.