diff --git a/app/model_manager.py b/app/model_manager.py
index 8f6e34b33..ba300eff2 100644
--- a/app/model_manager.py
+++ b/app/model_manager.py
@@ -35,7 +35,17 @@ class ModelFileManager:
             for folder in model_types:
                 if folder in folder_black_list:
                     continue
-                output_folders.append({"name": folder, "folders": folder_paths.get_folder_paths(folder)})
+                # Effective display filter: the folder's registered extension
+                # set, or the global supported_pt_extensions for match-all
+                # folders (empty set), resolved live so runtime registrations
+                # by custom nodes are reflected.
+                registered = folder_paths.folder_names_and_paths[folder][1]
+                effective = set(registered) if registered else set(folder_paths.supported_pt_extensions)
+                output_folders.append({
+                    "name": folder,
+                    "folders": folder_paths.get_folder_paths(folder),
+                    "extensions": sorted(effective),
+                })
             return web.json_response(output_folders)
 
         # NOTE: This is an experiment to replace `/models/{folder}`
diff --git a/openapi.yaml b/openapi.yaml
index c37d543c7..02fa2b7d6 100644
--- a/openapi.yaml
+++ b/openapi.yaml
@@ -775,6 +775,14 @@ components:
         ModelFolder:
             description: Represents a folder containing models
             properties:
+                extensions:
+                    description: 'Effective file-extension display filter for this folder: the registered extension set, or the global supported model extensions for folders registered without one (match-all). Resolved live, so runtime registrations by custom nodes are reflected.'
+                    example:
+                        - .ckpt
+                        - .safetensors
+                    items:
+                        type: string
+                    type: array
                 folders:
                     description: List of paths where models of this type are stored
                     example:
diff --git a/tests-unit/app_test/model_manager_test.py b/tests-unit/app_test/model_manager_test.py
index ae59206f6..7111e4a5c 100644
--- a/tests-unit/app_test/model_manager_test.py
+++ b/tests-unit/app_test/model_manager_test.py
@@ -24,6 +24,28 @@ def app(model_manager):
     app.add_routes(routes)
     return app
 
+async def test_get_model_folders_includes_effective_extensions(aiohttp_client, app, tmp_path):
+    """Folders expose their effective display filter: the registered extension
+    set, or the global supported_pt_extensions for match-all (empty) folders."""
+    with patch('folder_paths.folder_names_and_paths', {
+        'test_checkpoints': ([str(tmp_path)], {'.safetensors', '.ckpt'}),
+        'test_configs': ([str(tmp_path)], ['.yaml']),
+        'test_match_all': ([str(tmp_path)], set()),
+        'configs': ([str(tmp_path)], ['.yaml']),
+    }), patch('folder_paths.supported_pt_extensions', {'.safetensors', '.bin'}):
+        client = await aiohttp_client(app)
+        response = await client.get('/experiment/models')
+
+        assert response.status == 200
+        folders = {f['name']: f for f in await response.json()}
+
+        assert 'configs' not in folders  # blocklisted
+        assert folders['test_checkpoints']['folders'] == [str(tmp_path)]
+        assert folders['test_checkpoints']['extensions'] == ['.ckpt', '.safetensors']
+        assert folders['test_configs']['extensions'] == ['.yaml']
+        # Match-all folders substitute the live global set.
+        assert folders['test_match_all']['extensions'] == ['.bin', '.safetensors']
+
 async def test_get_model_preview_safetensors(aiohttp_client, app, tmp_path):
     img = Image.new('RGB', (100, 100), 'white')
     img_byte_arr = BytesIO()