“通过协议的”可以翻译为“by agreement” 或者 “through an agreement” ，具体使用哪个可根据语境和表达习惯来选择。例如：
The issue was resolved by agreement between the two parties.（这个问题通过双方的协议得到了解决。 ）
This change was made through an agreement reached at the last meeting.（这一变更是在上次会议上达成的协议中做出的。 ）