fix(guardrail_endpoints): handle string ui_type values in _build_field_dict

_build_field_dict unconditionally called .value on ui_type, which crashes
for guardrail configs that use plain strings (e.g. BlockCodeExecutionGuardrailConfigModel
uses "multiselect" and "percentage"). Now checks with hasattr before calling .value.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

litellm/proxy/guardrails/guardrail_endpoints.py

@@ -1173,7 +1173,8 @@ def _build_field_dict(
     # Check for custom UI type override
     field_json_schema_extra = getattr(field, "json_schema_extra", {})
     if field_json_schema_extra and "ui_type" in field_json_schema_extra:
-        field_type = field_json_schema_extra["ui_type"].value
+        ui_type = field_json_schema_extra["ui_type"]
+        field_type = ui_type.value if hasattr(ui_type, "value") else ui_type
     elif field_json_schema_extra and "type" in field_json_schema_extra:
         field_type = field_json_schema_extra["type"]
 

tests/test_litellm/proxy/guardrails/test_guardrail_endpoints.py

@@ -1103,4 +1103,47 @@ async def test_get_guardrail_info_endpoint_db_guardrail(mocker):
     assert isinstance(result, GuardrailInfoResponse)
     assert result.guardrail_id == "test-db-guardrail"
     assert result.guardrail_name == "Test DB Guardrail"
-    assert result.guardrail_definition_location == "db"
+    assert result.guardrail_definition_location == "db"
+
+
+class TestBuildFieldDict:
+    """Test _build_field_dict handles both enum and string ui_type values."""
+
+    def test_build_field_dict_with_string_ui_type(self):
+        """Test that _build_field_dict works when ui_type is a plain string (e.g. BlockCodeExecutionGuardrailConfigModel)."""
+        from unittest.mock import MagicMock
+
+        from litellm.proxy.guardrails.guardrail_endpoints import _build_field_dict
+
+        field = MagicMock()
+        field.json_schema_extra = {"ui_type": "multiselect", "options": ["python", "javascript"]}
+
+        result = _build_field_dict(
+            field=field,
+            field_annotation=str,
+            description="Test field",
+            required=False,
+        )
+
+        assert result["type"] == "multiselect"
+        assert result["description"] == "Test field"
+
+    def test_build_field_dict_with_enum_ui_type(self):
+        """Test that _build_field_dict works when ui_type is a GuardrailParamUITypes enum."""
+        from unittest.mock import MagicMock
+
+        from litellm.proxy.guardrails.guardrail_endpoints import _build_field_dict
+        from litellm.types.guardrails import GuardrailParamUITypes
+
+        field = MagicMock()
+        field.json_schema_extra = {"ui_type": GuardrailParamUITypes.BOOL}
+
+        result = _build_field_dict(
+            field=field,
+            field_annotation=bool,
+            description="Test bool field",
+            required=True,
+        )
+
+        assert result["type"] == "bool"
+        assert result["required"] is True