Types of insurance a contractor should have for an ADU

[Jesse Aizenstat]

We're building an ADU from the ground up. I thought the contractor should have "workers compensation" for him and everyone he brings to the job site. But I learned that my homeowners insurance has a 500k workers compensation policy (Safeco). When I described my situation to the agent, we boosted my secondary unit coverage (from a garage 34k, to a unit 300k) and that was about it.

If were to become "Additionally Insured" under the contractors general liability insurance, with my workers compensation, would that seem like sufficient coverage?

Any recommendations here?

Thanks everyone in advance! What makes these ADU's interesting is that they seem to walk the line between residential lending, permitting of utilities, fees, but also have a commercial element as they are built as rentals. Our ADU is a 874 SF unit in our backyard. It's a 2/2.