It’s not said explicitly, but the suggestion is very clear: Monica Rambeau is a S.W.O.R.D. agent who was sent into Westview to try and help Wanda deal with whatever issue she is battling.
So what does this mean?
Clearly the effort doesn’t end well, but it may be WandaVision’s gateway into telling us more about what’s going on outside the “situation,” as Monica will surely have to report to a superior what she witnessed while in Westview and what’s going on.
We’ve known from the very end of the first episode that the agency is monitoring what’s going on, and in the second there was that outreach call sent through the radio, but now things have been taken a step further with “undercover” agents seemingly being a part of the mix as well and physically entering the affected space.