diff --git a/predicators/envs/spot_env.py b/predicators/envs/spot_env.py
index 7835a9ca2b..20fb77a8a1 100644
--- a/predicators/envs/spot_env.py
+++ b/predicators/envs/spot_env.py
@@ -94,12 +94,12 @@ class _PartialPerceptionState(State):
     in the classifier definitions for the dummy predicates
     """
 
-    # DEBUG Add an additional field to store Spot images
-    # This would be directly copied from the images in raw Observation
-    # NOTE: This is only used when using VLM for predicate evaluation
-    # NOTE: Performance aspect should be considered later
-    obs_images: Optional[Dict[str, RGBDImageWithContext]] = None
-    # TODO: it's still unclear how we select and store useful images!
+    # # DEBUG Add an additional field to store Spot images
+    # # This would be directly copied from the images in raw Observation
+    # # NOTE: This is only used when using VLM for predicate evaluation
+    # # NOTE: Performance aspect should be considered later
+    # cam_images: Optional[Dict[str, RGBDImageWithContext]] = None
+    # # TODO: it's still unclear how we select and store useful images!
 
     @property
     def _simulator_state_predicates(self) -> Set[Predicate]:
@@ -128,7 +128,8 @@ def copy(self) -> State:
             "atoms": self._simulator_state_atoms.copy()
         }
         return _PartialPerceptionState(state_copy,
-                                       simulator_state=sim_state_copy)
+                                       simulator_state=sim_state_copy,
+                                       camera_images=self.camera_images)
 
 
 def _create_dummy_predicate_classifier(
@@ -1114,10 +1115,16 @@ def _object_in_xy_classifier(state: State,
 
 def _on_classifier(state: State, objects: Sequence[Object]) -> bool:
     obj_on, obj_surface = objects
+    currently_visible = all([o in state.visible_objects for o in objects])
 
-    if CFG.spot_vlm_eval_predicate:
-        print("TODO!!")
-        print(state.camera_images)
+    print(currently_visible, state)
+
+    if CFG.spot_vlm_eval_predicate and not currently_visible:
+        # TODO: add all previous atoms to the state
+        raise NotImplementedError
+    elif CFG.spot_vlm_eval_predicate and currently_visible:
+        # TODO call VLM to evaluate predicate value
+        raise NotImplementedError
     else:
         # Check that the bottom of the object is close to the top of the surface.
         expect = state.get(obj_surface, "z") + state.get(obj_surface, "height") / 2
@@ -1143,27 +1150,39 @@ def _top_above_classifier(state: State, objects: Sequence[Object]) -> bool:
 
 def _inside_classifier(state: State, objects: Sequence[Object]) -> bool:
     obj_in, obj_container = objects
+    currently_visible = all([o in state.visible_objects for o in objects])
 
-    if not _object_in_xy_classifier(
-            state, obj_in, obj_container, buffer=_INSIDE_SURFACE_BUFFER):
-        return False
+    print(currently_visible, state)
 
-    obj_z = state.get(obj_in, "z")
-    obj_half_height = state.get(obj_in, "height") / 2
-    obj_bottom = obj_z - obj_half_height
-    obj_top = obj_z + obj_half_height
+    if CFG.spot_vlm_eval_predicate and not currently_visible:
+        # TODO: add all previous atoms to the state
+        raise NotImplementedError
+    elif CFG.spot_vlm_eval_predicate and currently_visible:
+        # TODO call VLM to evaluate predicate value
+        raise NotImplementedError
 
-    container_z = state.get(obj_container, "z")
-    container_half_height = state.get(obj_container, "height") / 2
-    container_bottom = container_z - container_half_height
-    container_top = container_z + container_half_height
+    else:
 
-    # Check that the bottom is "above" the bottom of the container.
-    if obj_bottom < container_bottom - _INSIDE_Z_THRESHOLD:
-        return False
+        if not _object_in_xy_classifier(
+                state, obj_in, obj_container, buffer=_INSIDE_SURFACE_BUFFER):
+            return False
 
-    # Check that the top is "below" the top of the container.
-    return obj_top < container_top + _INSIDE_Z_THRESHOLD
+        obj_z = state.get(obj_in, "z")
+        obj_half_height = state.get(obj_in, "height") / 2
+        obj_bottom = obj_z - obj_half_height
+        obj_top = obj_z + obj_half_height
+
+        container_z = state.get(obj_container, "z")
+        container_half_height = state.get(obj_container, "height") / 2
+        container_bottom = container_z - container_half_height
+        container_top = container_z + container_half_height
+
+        # Check that the bottom is "above" the bottom of the container.
+        if obj_bottom < container_bottom - _INSIDE_Z_THRESHOLD:
+            return False
+
+        # Check that the top is "below" the top of the container.
+        return obj_top < container_top + _INSIDE_Z_THRESHOLD
 
 
 def _not_inside_any_container_classifier(state: State,
@@ -1462,6 +1481,13 @@ def _get_sweeping_surface_for_container(container: Object,
     _IsSemanticallyGreaterThan
 }
 _NONPERCEPT_PREDICATES: Set[Predicate] = set()
+# NOTE: We maintain a list of predicates that we check via
+# NOTE: In the future, we may include an attribute to denote whether a predicate
+# is VLM perceptible or not.
+# NOTE: candidates: on, inside, door opened, blocking, not blocked, ...
+_VLM_EVAL_PREDICATES: {
+    _On, _Inside,
+}
 
 
 ## Operators (needed in the environment for non-percept atom hack)