> Early in my career I did this. Now I go the exact opposite tack. Tell your employer.
What prompted the change?
Any tips for the things that should be covered? Do you actually go into a lot of detail, or do you just suggest that the high-level area, and whether it's a commercial endeavor?
I just go really high level. Larger companies usually have a process, sometimes it is categorized under "conflicts of interest". My current side projects are non-commercial, so I just put together a 3 sentence description of the project & a link to the GitHub page. Generally if the lawyers have any questions then I answer those, but I don't go overboard providing info. In the end it's better for everyone to have clarity.
Early in my career I did this. Now I go the exact opposite tack. Tell your employer. Get it cleared in writing. If you work at a company where that is a problem, then consider your side projects non-commercial for perpetuity, or get a new job.