This plant is deadly poisonous. But there seems to be some disagreement on how deadly, which seems like something that would be easy to come to a conclusion on. Just don’t eat it.
Phytochemistry and biological activities of Agrostemma genus: A review by Aleksander Smakosz, Adam Matkowski, & Izabela Nawrot-Hadzik (2024) https://doi.org/10.3390/plants13121673