Timecop is a standalone app that can integrate with Harvest and Basecamp Classic. It tracks what project you're working on and how much time you spend or have spent on projects.

Policing trends, not actions

Timecop tracks what you do quite accurately, but it provides little indication of how much time is being spent while you're working; there's few ways to see how many seconds or minutes have passed since switching to a given project, even if it is easy to switch to a different project in the first place. It also doesn't automate "clocking out". But it does work well with related services and for tracking trends in time usage.

No danger to your workflow

Overall, Timecop is a fantastic way to keep track of what work you're doing and how much of it is getting done over weeks and months. It integrates with services that make this easier and it lets you switch between projects easily for more accurate tracking. It's less good for day-to-day time tracking and for setting alarms and reminders, so keep that in mind before you get it.