diff --git a/config_converter/validators/schema.py b/config_converter/validators/schema.py
index f91e1f9..9271417 100644
--- a/config_converter/validators/schema.py
+++ b/config_converter/validators/schema.py
@@ -1,9 +1,9 @@
 """Schema inference and validation module."""
 
 from dataclasses import dataclass, field
-from typing import Any, Dict, List, Optional, Tuple, Union
+from typing import Any, Dict, List, Optional, Tuple
 
-from pydantic import BaseModel, ValidationError, field_validator
+from pydantic import BaseModel, field_validator
 
 
 class SchemaType:
@@ -57,6 +57,10 @@ class InferredSchema:
     description: str = ""
     items: Optional[SchemaProperty] = None
 
+    def __post_init__(self) -> None:
+        if self.properties is None:
+            self.properties = []
+
     def to_dict(self) -> Dict[str, Any]:
         """Convert to dictionary."""
         result: Dict[str, Any] = {
@@ -199,7 +203,7 @@ class SchemaValidator:
 
     def validate(self, data: Any) -> Tuple[bool, List[str]]:
         """Validate data against schema."""
-        errors = []
+        errors: List[str] = []
         is_valid = self._validate_value(data, self.schema, "", errors)
         return is_valid, errors
 
@@ -226,9 +230,8 @@ class SchemaValidator:
                 prop_path = f"{path}.{prop.name}" if path else prop.name
                 if prop.name in value:
                     prop_value = value[prop.name]
-                    prop_schema = InferredSchema(
-                        root_type=prop.type, properties=prop.properties
-                    )
+                    prop_props: List[SchemaProperty] = prop.properties if prop.properties else []
+                    prop_schema = InferredSchema(root_type=prop.type, properties=prop_props)  # type: ignore[arg-type]
                     self._validate_value(prop_value, prop_schema, prop_path, errors)
                 elif prop.required:
                     errors.append(f"{prop_path}: required property missing")
@@ -238,10 +241,8 @@ class SchemaValidator:
                 errors.append(f"{path}: expected array, got {actual_type}")
                 return False
             if isinstance(value, list) and schema.items:
-                item_schema = InferredSchema(
-                    root_type=schema.items.type,
-                    properties=schema.items.properties if schema.items.properties else None,
-                )
+                item_props: List[SchemaProperty] = schema.items.properties if schema.items.properties else []
+                item_schema = InferredSchema(root_type=schema.items.type, properties=item_props)  # type: ignore[arg-type]
                 for i, item in enumerate(value):
                     self._validate_value(item, item_schema, f"{path}[{i}]", errors)