diff --git a/src/bonsai/bonsai/bim/import_ifc.py b/src/bonsai/bonsai/bim/import_ifc.py
index 57d8a1b6b8..a24ace134d 100644
--- a/src/bonsai/bonsai/bim/import_ifc.py
+++ b/src/bonsai/bonsai/bim/import_ifc.py
@@ -1143,7 +1143,7 @@ class IfcImportSettings:
     @staticmethod
     def factory(context=None, input_file=None, logger=None):
         scene_diff = bpy.context.scene.DiffProperties
-        props = bpy.context.scene.BIMProjectProperties
+        props = tool.Project.get_project_props()
         settings = IfcImportSettings()
         settings.input_file = input_file
         if logger is None:
diff --git a/src/bonsai/bonsai/bim/module/material/prop.py b/src/bonsai/bonsai/bim/module/material/prop.py
index b623083d5f..d95dec9ccd 100644
--- a/src/bonsai/bonsai/bim/module/material/prop.py
+++ b/src/bonsai/bonsai/bim/module/material/prop.py
@@ -111,6 +111,14 @@ class Material(PropertyGroup):
     has_style: BoolProperty(name="Has Style", default=True)
     total_elements: IntProperty(name="Total Elements")
 
+    if TYPE_CHECKING:
+        name: str
+        ifc_definition_id: int
+        is_category: bool
+        is_expanded: bool
+        has_style: bool
+        total_elements: int
+
 
 class BIMMaterialProperties(PropertyGroup):
     is_editing: BoolProperty(name="Is Editing", default=False)
@@ -126,9 +134,21 @@ class BIMMaterialProperties(PropertyGroup):
 
     @property
     def active_material(self):
-        if self.active_material_index < len(self.materials):
+        if 0 <= self.active_material_index < len(self.materials):
             return self.materials[self.active_material_index]
 
+    if TYPE_CHECKING:
+        is_editing: bool
+        material_type: str
+        materials: bpy.types.bpy_prop_collection_idprop[Material]
+        active_material_index: int
+        profiles: str
+        active_material_id: int
+        material_attributes: bpy.types.bpy_prop_collection_idprop[Attribute]
+        editing_material_type: str
+        styles: str
+        contexts: str
+
 
 class BIMObjectMaterialProperties(PropertyGroup):
     material_type: EnumProperty(items=get_object_material_type, name="Material Type")
@@ -146,3 +166,16 @@ class BIMObjectMaterialProperties(PropertyGroup):
     parameterized_profile_classes: EnumProperty(
         items=get_parameterized_profile_classes, name="Parameterized Profile Classes"
     )
+
+    if TYPE_CHECKING:
+        material_type: str
+        material: str
+        is_editing: bool
+        material_set_usage_attributes: bpy.types.bpy_prop_collection_idprop[Attribute]
+        material_set_attributes: bpy.types.bpy_prop_collection_idprop[Attribute]
+        active_material_set_item_id: int
+        material_set_item_attributes: bpy.types.bpy_prop_collection_idprop[Attribute]
+        material_set_item_profile_attributes: bpy.types.bpy_prop_collection_idprop[Attribute]
+        material_set_item_material: str
+        profile_classes: str
+        parameterized_profile_classes: str
diff --git a/src/bonsai/bonsai/bim/module/material/ui.py b/src/bonsai/bonsai/bim/module/material/ui.py
index e787e199d4..1ac0936dea 100644
--- a/src/bonsai/bonsai/bim/module/material/ui.py
+++ b/src/bonsai/bonsai/bim/module/material/ui.py
@@ -16,6 +16,7 @@
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import annotations
 import bonsai.bim.helper
 import bonsai.tool as tool
 import bpy
@@ -25,6 +26,10 @@ from bonsai.bim.helper import draw_attributes
 from bonsai.bim.helper import prop_with_search
 from bonsai.bim.module.material.data import MaterialsData, ObjectMaterialData
 from bonsai.bim.module.drawing.helper import format_distance
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from bonsai.bim.module.material.prop import Material
 
 
 class BIM_PT_materials(Panel):
@@ -395,7 +400,9 @@ class BIM_PT_object_material(Panel):
 
 
 class BIM_UL_materials(UIList):
-    def draw_item(self, context, layout, data, item, icon, active_data, active_propname):
+    def draw_item(
+        self, context, layout: bpy.types.UILayout, data, item: Material, icon, active_data, active_propname
+    ) -> None:
         mprops = context.scene.BIMMaterialProperties
         material_type = mprops.material_type
 
diff --git a/src/bonsai/bonsai/bim/module/project/operator.py b/src/bonsai/bonsai/bim/module/project/operator.py
index 1ef8fd022d..48128f1643 100644
--- a/src/bonsai/bonsai/bim/module/project/operator.py
+++ b/src/bonsai/bonsai/bim/module/project/operator.py
@@ -207,7 +207,7 @@ class RefreshLibrary(bpy.types.Operator):
     bl_label = "Refresh Library"
 
     def execute(self, context):
-        self.props = context.scene.BIMProjectProperties
+        self.props = tool.Project.get_project_props()
 
         self.props.library_elements.clear()
         self.props.library_breadcrumb.clear()
@@ -227,11 +227,16 @@ class ChangeLibraryElement(bpy.types.Operator):
     bl_options = {"REGISTER", "UNDO"}
     element_name: bpy.props.StringProperty()
 
+    if TYPE_CHECKING:
+        element_name: str
+
     def execute(self, context):
-        self.props = context.scene.BIMProjectProperties
-        self.file = IfcStore.get_file()
-        self.library_file = IfcStore.library_file
-        ifc_classes = set()
+        self.props = tool.Project.get_project_props()
+        self.file = tool.Ifc.get()
+        library_file = IfcStore.library_file
+        assert library_file
+        self.library_file = library_file
+        ifc_classes: set[str] = set()
         self.props.active_library_element = self.element_name
 
         crumb = self.props.library_breadcrumb.add()
diff --git a/src/bonsai/bonsai/bim/module/project/prop.py b/src/bonsai/bonsai/bim/module/project/prop.py
index 349497cb7a..7cdf062e18 100644
--- a/src/bonsai/bonsai/bim/module/project/prop.py
+++ b/src/bonsai/bonsai/bim/module/project/prop.py
@@ -34,6 +34,7 @@ from bpy.props import (
     IntProperty,
     StringProperty,
 )
+from typing import TYPE_CHECKING, Literal, Union
 
 
 def get_export_schema(self: "BIMProjectProperties", context: bpy.types.Context) -> list[tuple[str, str, str]]:
@@ -97,11 +98,18 @@ def update_filter_mode(self: "BIMProjectProperties", context: bpy.types.Context)
 
 
 class LibraryElement(PropertyGroup):
+    # For IFC class groups only name is filled, for assets - all fields.
     name: StringProperty(name="Name")
     ifc_definition_id: IntProperty(name="IFC Definition ID")
     is_declared: BoolProperty(name="Is Declared", default=False)
     is_appended: BoolProperty(name="Is Appended", default=False)
 
+    if TYPE_CHECKING:
+        name: str
+        ifc_definition_id: int
+        is_declared: bool
+        is_appended: bool
+
 
 class FilterCategory(PropertyGroup):
     name: StringProperty(name="Name")
@@ -109,6 +117,12 @@ class FilterCategory(PropertyGroup):
     is_selected: BoolProperty(name="Is Selected", default=False)
     total_elements: IntProperty(name="Total Elements")
 
+    if TYPE_CHECKING:
+        name: str
+        ifc_definition_id: int
+        is_selected: bool
+        total_elements: int
+
 
 class Link(PropertyGroup):
     name: StringProperty(
@@ -125,10 +139,21 @@ class Link(PropertyGroup):
         type=bpy.types.Object,
     )
 
+    if TYPE_CHECKING:
+        name: str
+        is_loaded: bool
+        is_selectable: bool
+        is_wireframe: bool
+        is_hidden: bool
+        empty_handle: Union[bpy.types.Object, None]
+
 
 class EditedObj(PropertyGroup):
     obj: PointerProperty(type=bpy.types.Object)
 
+    if TYPE_CHECKING:
+        obj: Union[bpy.types.Object, None]
+
 
 class BIMProjectProperties(PropertyGroup):
     is_editing: BoolProperty(name="Is Editing", default=False)
@@ -238,12 +263,62 @@ class BIMProjectProperties(PropertyGroup):
     edited_objs: bpy.props.CollectionProperty(type=EditedObj)
 
     @property
-    def clipping_planes_objs(self):
+    def clipping_planes_objs(self) -> list[bpy.types.Object]:
         return list({cp.obj for cp in self.clipping_planes if cp.obj})
 
-    def get_library_element_index(self, lib_element):
+    def get_library_element_index(self, lib_element: LibraryElement) -> int:
         return next((i for i in range(len(self.library_elements)) if self.library_elements[i] == lib_element))
 
+    if TYPE_CHECKING:
+        is_editing: bool
+        is_loading: bool
+        mvd: str
+        author_name: str
+        author_email: str
+        organisation_name: str
+        organisation_email: str
+        authorisation: str
+        active_library_element: str
+        library_breadcrumb: bpy.types.bpy_prop_collection_idprop[StrProperty]
+        library_elements: bpy.types.bpy_prop_collection_idprop[LibraryElement]
+        active_library_element_index: int
+        filter_mode: Literal["NONE", "DECOMPOSITION", "IFC_CLASS", "IFC_TYPE", "WHITELIST", "BLACKLIST"]
+        total_elements: int
+        filter_categories: bpy.types.bpy_prop_collection_idprop[FilterCategory]
+        active_filter_category_index: int
+        filter_query: str
+        should_filter_spatial_elements: bool
+        geometry_library: Literal["opencascade", "cgal", "cgal-simple", "hybrid-cgal-simple-opencascade"]
+        should_use_cpu_multiprocessing: bool
+        should_merge_materials_by_colour: bool
+        should_stream: bool
+        should_load_geometry: bool
+        should_clean_mesh: bool
+        should_cache: bool
+        deflection_tolerance: float
+        angular_tolerance: float
+        void_limit: int
+        distance_limit: float
+        false_origin_mode: Literal["AUTOMATIC", "MANUAL", "DISABLED"]
+        false_origin: str
+        project_north: str
+        element_limit_mode: Literal["UNLIMITED", "RANGE"]
+        element_offset: int
+        element_limit: int
+        load_indexed_maps: bool
+        should_disable_undo_on_save: bool
+        links: bpy.types.bpy_prop_collection_idprop[Link]
+        active_link_index: int
+        export_schema: str
+        template_file: str
+        library_file: str
+        use_relative_project_path: bool
+        queried_obj: Union[bpy.types.Object, None]
+        queried_obj_root: Union[bpy.types.Object, None]
+        clipping_planes: bpy.types.bpy_prop_collection_idprop[ObjProperty]
+        clipping_planes_active: int
+        edited_objs: bpy.types.bpy_prop_collection_idprop[EditedObj]
+
 
 class MeasureToolSettings(PropertyGroup):
     measurement_type_items = [
@@ -253,3 +328,6 @@ class MeasureToolSettings(PropertyGroup):
     ]
 
     measurement_type: bpy.props.EnumProperty(items=measurement_type_items, default="POLYLINE")
+
+    if TYPE_CHECKING:
+        measurement_type: Literal["SINGLE", "POLYLINE", "AREA"]
diff --git a/src/bonsai/bonsai/bim/module/project/ui.py b/src/bonsai/bonsai/bim/module/project/ui.py
index bcc50b1690..2613ed1245 100644
--- a/src/bonsai/bonsai/bim/module/project/ui.py
+++ b/src/bonsai/bonsai/bim/module/project/ui.py
@@ -16,6 +16,8 @@
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import annotations
+import bpy
 import os
 import bonsai.bim
 import bonsai.tool as tool
@@ -23,6 +25,10 @@ from bonsai.bim.helper import prop_with_search
 from bpy.types import Panel, Menu, UIList
 from bonsai.bim.ifc import IfcStore
 from bonsai.bim.module.project.data import ProjectData, LinksData
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from bonsai.bim.module.project.prop import LibraryElement, BIMProjectProperties
 
 
 def file_import_menu(self, context):
@@ -441,7 +447,16 @@ class BIM_PT_links(Panel):
 
 
 class BIM_UL_library(UIList):
-    def draw_item(self, context, layout, data, item, icon, active_data, active_propname):
+    def draw_item(
+        self,
+        context,
+        layout: bpy.types.UILayout,
+        data: BIMProjectProperties,
+        item: LibraryElement,
+        icon,
+        active_data,
+        active_propname,
+    ):
         if item:
             row = layout.row(align=True)
             if not item.ifc_definition_id:
diff --git a/src/bonsai/bonsai/tool/project.py b/src/bonsai/bonsai/tool/project.py
index ca4350def0..ea137067a3 100644
--- a/src/bonsai/bonsai/tool/project.py
+++ b/src/bonsai/bonsai/tool/project.py
@@ -16,6 +16,7 @@
 # You should have received a copy of the GNU General Public License
 # along with Bonsai.  If not, see <http://www.gnu.org/licenses/>.
 
+from __future__ import annotations
 import os
 import bpy
 import ifcopenshell
@@ -33,10 +34,17 @@ import bonsai.tool as tool
 from bonsai.bim.ifc import IfcStore
 from ifcopenshell.api.project.append_asset import APPENDABLE_ASSET_TYPES
 from pathlib import Path
-from typing import Optional, Union
+from typing import Optional, Union, TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from bonsai.bim.module.project.prop import BIMProjectProperties
 
 
 class Project(bonsai.core.tool.Project):
+    @classmethod
+    def get_project_props(cls) -> BIMProjectProperties:
+        return bpy.context.scene.BIMProjectProperties
+
     @classmethod
     def append_all_types_from_template(cls, template: str) -> None:
         # TODO refactor