This type of "contract" is really to help you keep safe, and put the control for safety into your own hands.

For some, whether for suicide or other self harm, it can be made once and continued as an ongoing agreement.

For others, who are in the throes of ideation, it might only be for a few days or a week, until the next therapy session when it will be discussed again and a new contract made.

It can have whatever provisions that you both agree upon. (You being T and you.) Some therapists can ask that you call them and talk to them prior to making any other decision of action. Some don't have that capability and do ask that you go to the ER when feeling that out of control (that you can't prevent yourself.)

It might feel like the end of the world, having to do this, but it will work out for you. It's in your own best interest to make them and work hard to keep them. If you find you can't keep them then the time limit might be too long, and you may need contact more often with your T to help support you not to do anything.