Legal Consequences of Peace Negotiations Between Ukraine and the USA

I read that negotiations are planned between Ukraine and the USA, involving military personnel, regarding the preparation of a possible peace agreement. I am curious, if such an agreement is signed, will the Ukrainian authorities be obliged to adhere to all its terms? And if something in it turns out to be unfavorable for citizens or contradicts the laws of Ukraine, can we somehow challenge or influence its implementation at the legislative level?