The entire plot of episode 2 was about putting the idea of having kids in Wanda's head. Then, the entire plot of episode 5 was about the kids putting the idea of bringing back the dead in her head. In both episodes, Agnes is the main instigator of events (bringing Wanda to the fundraiser and being the first to mention kids, pushing them to keep the dog and then being the one to find it dead).
It's all been orchestrated to bring Pietro in, and now that he's here he seems to be an antagonist. He claims that he doesn't remember anything between being killed by Ultron and Wanda calling him back, but he knows that Vision died. He doesn't question that Wanda created Westview even though he'd never seen her do anything close to that before. He dodges questions about their past and makes up stuff she doesn't remember. I don't know if he's a secret villain (a lot of people seem to think Mephisto will be in this show) or just a disruptive force to try and break her out of the illusion world, but it's all been about bringing him in and Agnes played a key role in that, with more apparent agency than anyone else in town.