When I use too in the sense of “also,” should I use a comma before it?
In most cases, you need not use a comma before too at the end of a sentence or commas around it midsentence:
She likes chocolate chip cookies too.
She too likes chocolate chip cookies.
But, as usage experts note, you must use commas when too separates the verb from its object (Cook 126):
I note, too, that you have eaten all the chocolate chip cookies.
Cook, Claire Kehrwald. Line by Line: How to Edit Your Own Writing. Houghton Mifflin Harcourt, 1985.