local chrome mode is only supported on Linux
Google is best at what it does. Screwing up paid customers 
They make a product, users start paying and when it’s broken there’s no way to get any support.
I’m not expecting any resolution to this, just leaving this error message which many other’s have reported and Google gives a shit about this, and quite possible Antigravity will be end of life very soon.
I attempted to open the <URL> URL, but the open_browser_url tool failed with the following error:
local chrome mode is only supported on Linux
Since this task is running on a macOS environment and the browser subagent cannot initialize the local Chrome instance, I am unable to proceed with navigating the browser.