diff --git a/greens/routers/v1/vegs.py b/greens/routers/v1/vegs.py
index 74bbf1d..2273cf7 100644
--- a/greens/routers/v1/vegs.py
+++ b/greens/routers/v1/vegs.py
@@ -16,7 +16,7 @@
     "",
     status_code=HTTP_201_CREATED,
     response_description="Document created",
-    # response_model=DocumentResponse,
+    response_model=DocumentResponse,
 )
 async def add_document(payload: Document):
     """
@@ -45,7 +45,7 @@ async def get_document(object_id: ObjectIdField):
     """
     try:
         return await retrieve_document(object_id, collection)
-    except ValueError as exception:
+    except (ValueError, TypeError) as exception:
         raise NotFoundHTTPException(msg=str(exception)) from exception
 
 
diff --git a/greens/schemas/vegs.py b/greens/schemas/vegs.py
index 1b36bdf..1e74b6f 100644
--- a/greens/schemas/vegs.py
+++ b/greens/schemas/vegs.py
@@ -1,27 +1,46 @@
 from bson import ObjectId as _ObjectId
 from bson.errors import InvalidId
-from pydantic import BaseModel, Field, ConfigDict, AfterValidator
+from pydantic import BaseModel, Field, ConfigDict, AfterValidator, BeforeValidator
 from typing_extensions import Annotated
 
 
-def check_object_id(value: str) -> str:
+# def check_object_id(value: str) -> str:
+#     if not _ObjectId.is_valid(value):
+#         raise ValueError('Invalid ObjectId')
+#     return value
+
+
+def check_object_id(value: _ObjectId) -> str:
+    """
+    Checks if the given _ObjectId is valid and returns it as a string.
+
+    Args:
+        value: The _ObjectId to be checked.
+
+    Returns:
+        str: The _ObjectId as a string.
+
+    Raises:
+        ValueError: If the _ObjectId is invalid.
+    """
+
     if not _ObjectId.is_valid(value):
-        raise ValueError('Invalid ObjectId')
-    return value
+        raise ValueError("Invalid ObjectId")
+    return str(value)
 
 
-ObjectIdField = Annotated[str, AfterValidator(check_object_id)]
+ObjectIdField = Annotated[str, BeforeValidator(check_object_id)]
 
 
 config = ConfigDict(arbitrary_types_allowed=True, populate_by_name=True)
 
 
 class Document(BaseModel):
-    # model_config = config
+    model_config = config
 
-    name: str = Field(...)
-    desc: str = Field(...)
+    name: str
+    desc: str
 
 
 class DocumentResponse(BaseModel):
-    id: ObjectIdField = Field(...)
+    id: ObjectIdField
diff --git a/tests/test_schemas.py b/tests/test_schemas.py
index 77ec27d..64c45ee 100644
--- a/tests/test_schemas.py
+++ b/tests/test_schemas.py
@@ -30,7 +30,7 @@ def test_document_response_with_valid_id(test_id, object_id):
     document_response = DocumentResponse(id=object_id)
 
     # Assert
-    assert document_response.id == object_id, f"Test case {test_id} failed: The id field did not match the input ObjectId."
+    assert document_response.id == str(object_id), f"Test case {test_id} failed: The id field did not match the input ObjectId."
 
 
 # Edge cases