Agency for me refers to free will, the free will to choose how I will act and react to lifes constantly changing situations. Will I ignore or take insult. Will I move forward or dwell on the past. Agency is the ultimate gift we receive.
For me, but represents the opposite of agency. It reflects ones lack of faith in themself, a belief that they are hampered from affecting their perception of reality. I could be be locked away in prison for life and still use agency to choose to find the positive in a restricted situation, or I could sit and feel sorry saying, "but I am in prison, I can't."