I've been using https://www.manictime.com for maybe close to 20 years now, although not the pro version that offers screenshot recording (curiously the website doesn't mention the existence of a free "standard" license). It records window titles and presence/away times.

A prompt every few minutes that would ask "What are you doing now?" would be interesting to me, as a professional procrastinator. Maybe an even better one would be one that says something like "In the last 10 minutes, you spent 90% of it on Hacker News".