Ask HN: Is automatic time tracking a solved problem?

I'm looking for a time tracker that doesn't require manual start/stop timers (like Toggl) or tedious, inaccurate rule-based categorization (like Rize/RescueTime). I want an app that runs in the background and can automatically figure out what I was doing — differentiating between focused work, meetings (via calendar integration), and distractions.

Everything I've tried is either too manual or not intelligent enough. Have you found a tool that gets this right? Or is this a harder problem to solve than it seems?