diff --git a/environments/factory/factory_cleaning.py b/environments/factory/factory_cleaning.py
index 4372579..8b35167 100644
--- a/environments/factory/factory_cleaning.py
+++ b/environments/factory/factory_cleaning.py
@@ -31,7 +31,8 @@ class Factory(object):
             actions = [actions]
         # level, agent 1,..., agent n,
         for i, a in enumerate(actions):
-            h.check_agent_move(state=self.state, dim=i+1, action=a)
+            old_pos, new_pos, valid = h.check_agent_move(state=self.state, dim=i+1, action=a)
+
 
 if __name__ == '__main__':
     factory = Factory(n_agents=1)
diff --git a/environments/helpers.py b/environments/helpers.py
index 57f593d..87abc56 100644
--- a/environments/helpers.py
+++ b/environments/helpers.py
@@ -28,6 +28,7 @@ def check_agent_move(state, dim, action):
         raise AssertionError('Only one agent per slice is allowed.')
     x, y = agent_pos[0]
     x_new, y_new = x, y
+    # Actions
     if action == 0: # North
         x_new -= 1
     elif action == 1: # East
@@ -48,6 +49,14 @@ def check_agent_move(state, dim, action):
     elif action == 7: # NW
         x_new -= 1
         y_new -= 1
+    # Check validity
+    valid = (x_new < 0 or y_new < 0
+             or x_new >= agent_slice.shape[0]
+             or y_new >= agent_slice.shape[0]
+             )
+    return (x, y), (x_new, y_new), valid
+
+