As I was being hired today, I was asked to sign a "Confidentiality and Inventions Assignment Agreement" which partly reads:
"I agree that all right (...) to any copyrightable material (...) conceived by me (...) solely or in collaboration with others (...) during the period of time that I am in the employ of [company name] (including during my off-duty hours) or with the use of [company]'s equipment (...) are the sole propriety of [company]."
However after a quick search online I have found from the respected Nolo website that:
"In California, for example, an invention assignment agreement is not valid as to inventions created entirely on the employee’s own time, without using any of the employer’s resources or property (including intellectual property)."
As a Designer, I fall in the category described on the page in the bullet list near the end:
Are you likely to invent during your employment? If you are a creative tinkerer, always coming up with ideas and improvements, you might not want to sign away your rights to earn some money off whatever you invent.
The document also has a blank page at the end where I am invited to add "List of prior inventions and original works of authorship", which would require a lot of time for me and also implies not only disclosing past and current projects, which might be extensive work and/or confidential, but also implies stopping work on them?
Is this agreement common practice, and what is a simple and quick way to make sure my ownership of my works outside of work is preserved?