diff --git a/src/mind_reader/core/__init__.py b/src/mind_reader/core/__init__.py
new file mode 100644
index 0000000..b5e32ec
--- /dev/null
+++ b/src/mind_reader/core/__init__.py
@@ -0,0 +1,5 @@
+from mind_reader.core.game_state import GameState
+
+__all__ = [
+    "GameState",
+]
diff --git a/src/mind_reader/core/game_state.py b/src/mind_reader/core/game_state.py
new file mode 100644
index 0000000..566463e
--- /dev/null
+++ b/src/mind_reader/core/game_state.py
@@ -0,0 +1,33 @@
+class GameState:
+    def __init__(self, local_player_name: str):
+        self.local_player_name: str = local_player_name
+        self.remote_player_name: str | None = None
+        self.lobby_players: dict[str, str] = {self.local_player_name: "NONE"}
+
+    def add_remote_player(self, player_name: str):
+        self.remote_player_name = player_name
+        self.lobby_players[self.remote_player_name] = "NONE"
+
+    def delete_remote_player(self):
+        if self.remote_player_name in self.lobby_players:
+            del self.lobby_players[self.remote_player_name]
+        self.remote_player_name = None
+
+    def set_player_role(self, player_name: str, role: str) -> bool:
+        current_role = self.lobby_players.get(player_name)
+        if current_role == role:
+            return False
+
+        if role in ["NONE", "SETTER", "GUESSER"]:
+            self.lobby_players[player_name] = role
+            return True
+
+        return False
+
+    @property
+    def local_player_role(self) -> str:
+        return self.lobby_players[self.local_player_name]
+
+    def is_session_ready(self) -> bool:
+        roles = list(self.lobby_players.values())
+        return ("SETTER" in roles) and ("GUESSER" in roles)