diff --git a/superset-core/src/superset_core/semantic_layers/decorators.py b/superset-core/src/superset_core/semantic_layers/decorators.py
index 50c67fc8028..50dd975702c 100644
--- a/superset-core/src/superset_core/semantic_layers/decorators.py
+++ b/superset-core/src/superset_core/semantic_layers/decorators.py
@@ -41,12 +41,10 @@ Usage:
 
 from __future__ import annotations
 
-from typing import Any, Callable, TypeVar
-
-from superset_core.semantic_layers.layer import SemanticLayer
+from typing import Callable, TypeVar
 
 # Type variable for decorated semantic layer classes
-T = TypeVar("T", bound=type[SemanticLayer[Any, Any]])
+T = TypeVar("T")
 
 
 def semantic_layer(
diff --git a/superset/core/api/core_api_injection.py b/superset/core/api/core_api_injection.py
index 4d2e88fcf7f..fb39f5d271a 100644
--- a/superset/core/api/core_api_injection.py
+++ b/superset/core/api/core_api_injection.py
@@ -237,7 +237,7 @@ def inject_semantic_layer_implementations() -> None:
     """
     import superset_core.semantic_layers.decorators as core_sl_module
 
-    from superset.extensions.context import get_current_extension_context
+    import superset.extensions.context as context_module
     from superset.semantic_layers.registry import registry
 
     def semantic_layer_impl(
@@ -246,9 +246,7 @@ def inject_semantic_layer_implementations() -> None:
         description: str | None = None,
     ) -> Callable[[Any], Any]:
         def decorator(cls: Any) -> Any:
-            context = get_current_extension_context()
-
-            if context:
+            if context := context_module.get_current_extension_context():
                 manifest = context.manifest
                 prefixed_id = f"extensions.{manifest.publisher}.{manifest.name}.{id}"
             else:
diff --git a/tests/unit_tests/semantic_layers/decorators_test.py b/tests/unit_tests/semantic_layers/decorators_test.py
index 2d475c55bbc..e52f6532de2 100644
--- a/tests/unit_tests/semantic_layers/decorators_test.py
+++ b/tests/unit_tests/semantic_layers/decorators_test.py
@@ -37,26 +37,27 @@ def test_semantic_layer_stub_raises() -> None:
 
 def test_inject_semantic_layer_host_context() -> None:
     """The injected decorator registers a class in host context."""
+    from superset.core.api.core_api_injection import (
+        inject_semantic_layer_implementations,
+    )
     from superset.semantic_layers.registry import registry
 
     # Clear registry for test isolation
     registry.clear()
 
-    with patch(
-        "superset.core.api.core_api_injection.get_current_extension_context",
-        return_value=None,
-    ):
-        from superset.core.api.core_api_injection import (
-            inject_semantic_layer_implementations,
-        )
-
-        inject_semantic_layer_implementations()
+    inject_semantic_layer_implementations()
 
     import superset_core.semantic_layers.decorators as mod
 
-    @mod.semantic_layer(id="test_layer", name="Test Layer", description="A test")
-    class FakeLayer:
-        pass
+    # Host context: no extension context active, so no prefix
+    with patch(
+        "superset.extensions.context.get_current_extension_context",
+        return_value=None,
+    ):
+
+        @mod.semantic_layer(id="test_layer", name="Test Layer", description="A test")
+        class FakeLayer:
+            pass
 
     assert "test_layer" in registry
     assert registry["test_layer"] is FakeLayer
@@ -69,6 +70,9 @@ def test_inject_semantic_layer_host_context() -> None:
 
 def test_inject_semantic_layer_extension_context() -> None:
     """The injected decorator prefixes ID in extension context."""
+    from superset.core.api.core_api_injection import (
+        inject_semantic_layer_implementations,
+    )
     from superset.semantic_layers.registry import registry
 
     registry.clear()
@@ -77,29 +81,19 @@ def test_inject_semantic_layer_extension_context() -> None:
     mock_context.manifest.publisher = "acme"
     mock_context.manifest.name = "analytics"
 
-    with patch(
-        "superset.core.api.core_api_injection.get_current_extension_context",
-        return_value=None,
-    ):
-        from superset.core.api.core_api_injection import (
-            inject_semantic_layer_implementations,
-        )
-
-        inject_semantic_layer_implementations()
+    inject_semantic_layer_implementations()
 
     import superset_core.semantic_layers.decorators as mod
 
-    # Now simulate extension context for the decorator call
+    # Extension context is checked at decorator call time via module lookup
     with patch(
-        "superset.core.api.core_api_injection.get_current_extension_context",
+        "superset.extensions.context.get_current_extension_context",
         return_value=mock_context,
     ):
-        # Re-inject so the closure captures the mock context
-        inject_semantic_layer_implementations()
 
-    @mod.semantic_layer(id="ext_layer", name="Extension Layer")
-    class ExtLayer:
-        pass
+        @mod.semantic_layer(id="ext_layer", name="Extension Layer")
+        class ExtLayer:
+            pass
 
     expected_id = "extensions.acme.analytics.ext_layer"
     assert expected_id in registry
diff --git a/tests/unit_tests/semantic_layers/mapper_test.py b/tests/unit_tests/semantic_layers/mapper_test.py
index 59587722065..7abdce91a6e 100644
--- a/tests/unit_tests/semantic_layers/mapper_test.py
+++ b/tests/unit_tests/semantic_layers/mapper_test.py
@@ -1004,7 +1004,7 @@ def test_convert_query_object_filter_unknown_operator(
     mock_datasource: MagicMock,
 ) -> None:
     """
-    Test filter with unknown operator returns None.
+    Test filter with unknown operator raises ValueError.
     """
     all_dimensions = {
         dim.name: dim for dim in mock_datasource.implementation.dimensions
@@ -1016,9 +1016,8 @@ def test_convert_query_object_filter_unknown_operator(
         "val": "Electronics",
     }
 
-    result = _convert_query_object_filter(filter_, all_dimensions)
-
-    assert result is None
+    with pytest.raises(ValueError, match="Unsupported filter operator"):
+        _convert_query_object_filter(filter_, all_dimensions)
 
 
 def test_validate_query_object_undefined_metric_error(