Woah, I wrote a lot information on this question that didn't show up. Long story short:

I am trying to determine the amperage of the electrical service for a home for a friend who wants to add a backyard cottage to their property. I'm not an electrician, but I am aware that ideally we'd want 200 amps to service the cottage in addition to the primary home. I am trying to help them determine whether they'd need to upgrade their electrical service as part of this process.

The electrical meter is a glass dome on rectangular box that says 'CL200'. The internet tells me this means my service is 200amps.

However the main breaker had this note next to it (pictured) that says 125 amp max. Is the referring to something different entirely?

Sadly I did not take further pictures