Legal Question in Constitutional Law in Montana

Your question is about employment law, not constitutional law. Please re-post it under that heading.

I'm no expert on employment law, even here in California. But in general, an employer is allowed to do what you describe unless doing so would breach an existing contract with the employee. That could mean an individual contract, a collective-bargaining agreement, or a combination of the two. In some states, the contract could be either oral or written. And in at least some states, the written contract need not be in the form of a formal, signed agreement. (For example, an employee handbook might be part of such a contract. So might emails between the employee and his superiors.)

Even if the employer has the right to make you sign this type of agreement, the particular agreement they want you to sign might be improper.

My point is that your question is not simple, and that the answer might vary quite a bit from one state to another. You will be more likely to get answers from lawyers who have the relevant expertise if you re-post it under Montana employment law. And if you can, you should meet with such a lawyer and go over the proposed agreement with her.

Good luck