diff --git a/templates/api/handler.py b/templates/api/handler.py
index d6d3e95..fe2e9b7 100644
--- a/templates/api/handler.py
+++ b/templates/api/handler.py
@@ -6,6 +6,7 @@
 
 from templates.api.models import Item
 from templates.api.response import JsonResponse
+from templates.models import Entity
 from templates.api.settings import Settings
 from templates.repository import Repository
 
@@ -27,8 +28,13 @@ def get_item(id: str) -> Response:
         id: The unique identifier of the item.
 
     Returns:
-        200 with the item, 404 if not found, or 500 on error.
+        200 with the item, 400 on invalid ID, 404 if not found, or 500 on error.
     """
+    try:
+        Entity(id=id)
+    except ValidationError:
+        return JsonResponse({"message": "Invalid item ID length"}, status_code=400)
+
     try:
         if (item := repository.get_item(id)) is None:
             return JsonResponse({"message": f"Item '{id}' not found"}, status_code=404)
@@ -51,10 +57,10 @@ def create_item() -> Response:
     try:
         item = Item.model_validate_json(app.current_event.body)
     except ValidationError as exc:
-        return JsonResponse({"errors": exc.errors()}, status_code=422)
+        return JsonResponse({"errors": exc.errors(include_input=False, include_url=False)}, status_code=422)
 
     try:
-        repository.put_item(item.model_dump())
+        repository.put_item(item.dump())
     except Exception as exc:
         logger.error("DynamoDB put_item failed", exc_info=exc, extra={"itemId": item.id})
         return JsonResponse({"message": "Internal server error"}, status_code=500)
diff --git a/tests/api/test_handler.py b/tests/api/test_handler.py
index 76ea911..4bc8378 100644
--- a/tests/api/test_handler.py
+++ b/tests/api/test_handler.py
@@ -99,6 +99,19 @@ def test_get_item_not_found(mock_repo, lambda_context):
     assert body["message"] == "Item 'missing' not found"
 
 
+def test_get_item_id_too_long(mock_repo, lambda_context):
+    """GET /items/{id} returns 400 when the ID exceeds 50 characters."""
+    import templates.api.handler as handler_module
+
+    long_id = "a" * 51
+    event = _apigw_event("GET", f"/items/{long_id}", path_params={"id": long_id})
+    response = handler_module.main(event, lambda_context)
+
+    assert response["statusCode"] == 400
+    body = loads(response["body"])
+    assert body["message"] == "Invalid item ID length"
+
+
 def test_post_item_invalid_body(mock_repo, lambda_context):
     """POST /items returns 422 when the request body fails Pydantic validation."""
     import templates.api.handler as handler_module
@@ -123,6 +136,10 @@ def test_post_item_name_too_long(mock_repo, lambda_context):
     body = loads(response["body"])
     assert "errors" in body
     assert any(err["type"] == "string_too_long" for err in body["errors"])
+    # Verify sanitization (no input, no url)
+    for error in body["errors"]:
+        assert "input" not in error
+        assert "url" not in error
 
 
 def test_get_item_dynamodb_error(mock_repo, lambda_context):