Expensive 4o-mini calls keep happening during agent mode

each 4o-mini call is a premium request, and I am currently billed for 30 of them. I looked through my usage reports, and found out that a lot of these are during my Claude 4.5 agent session in vscode. I don't understand what exactly I am doing that is incurring these charges, shouldn't I only be charged for how many prompts I send?
Am I doing something wrong? what can I improve in my usage?
(Last month I found out that sending images to copilot chat is also a premium request per image, so I stopped doing that).