diff --git a/mpt_api_client/models/__init__.py b/mpt_api_client/models/__init__.py
index 8c29ac9c..0c6be133 100644
--- a/mpt_api_client/models/__init__.py
+++ b/mpt_api_client/models/__init__.py
@@ -1,6 +1,23 @@
+from mpt_api_client.models.attachment_model import AttachmentModel
+from mpt_api_client.models.document_model import DocumentModel
 from mpt_api_client.models.file_model import FileModel
+from mpt_api_client.models.file_resource_model import FileResourceModel
+from mpt_api_client.models.media_model import MediaModel
 from mpt_api_client.models.meta import Meta, Pagination
 from mpt_api_client.models.model import Model, ResourceData
 from mpt_api_client.models.model_collection import ModelCollection
+from mpt_api_client.models.term_variant_model import TermVariantModel
 
-__all__ = ["FileModel", "Meta", "Model", "ModelCollection", "Pagination", "ResourceData"]  # noqa: WPS410
+__all__ = [  # noqa: WPS410
+    "AttachmentModel",
+    "DocumentModel",
+    "FileModel",
+    "FileResourceModel",
+    "MediaModel",
+    "Meta",
+    "Model",
+    "ModelCollection",
+    "Pagination",
+    "ResourceData",
+    "TermVariantModel",
+]
diff --git a/mpt_api_client/models/attachment_model.py b/mpt_api_client/models/attachment_model.py
new file mode 100644
index 00000000..30727007
--- /dev/null
+++ b/mpt_api_client/models/attachment_model.py
@@ -0,0 +1,5 @@
+from mpt_api_client.models.file_resource_model import FileResourceModel
+
+
+class AttachmentModel(FileResourceModel):
+    """Base model for attachment resources. Inherits fields from FileResourceModel."""
diff --git a/mpt_api_client/models/document_model.py b/mpt_api_client/models/document_model.py
new file mode 100644
index 00000000..86b801f5
--- /dev/null
+++ b/mpt_api_client/models/document_model.py
@@ -0,0 +1,15 @@
+from mpt_api_client.models.file_resource_model import FileResourceModel
+
+
+class DocumentModel(FileResourceModel):
+    """Base model for document resources.
+
+    Attributes:
+        status: Document status.
+        filename: Original file name.
+        url: URL to access the document.
+    """
+
+    status: str | None = None
+    filename: str | None = None
+    url: str | None = None
diff --git a/mpt_api_client/models/file_resource_model.py b/mpt_api_client/models/file_resource_model.py
new file mode 100644
index 00000000..4b798451
--- /dev/null
+++ b/mpt_api_client/models/file_resource_model.py
@@ -0,0 +1,19 @@
+from mpt_api_client.models.model import Model
+
+
+class FileResourceModel(Model):
+    """Base model for file-like resources (attachments, documents, media, term variants).
+
+    Attributes:
+        name: Resource name.
+        type: Resource type.
+        size: File size in bytes.
+        description: Resource description.
+        content_type: MIME content type.
+    """
+
+    name: str | None = None
+    type: str | None = None
+    size: int | None = None
+    description: str | None = None
+    content_type: str | None = None
diff --git a/mpt_api_client/models/media_model.py b/mpt_api_client/models/media_model.py
new file mode 100644
index 00000000..5e2405d5
--- /dev/null
+++ b/mpt_api_client/models/media_model.py
@@ -0,0 +1,17 @@
+from mpt_api_client.models.file_resource_model import FileResourceModel
+
+
+class MediaModel(FileResourceModel):
+    """Base model for media resources.
+
+    Attributes:
+        status: Media status.
+        filename: Original file name.
+        display_order: Display order of the media item.
+        url: URL to access the media file.
+    """
+
+    status: str | None = None
+    filename: str | None = None
+    display_order: int | None = None
+    url: str | None = None
diff --git a/mpt_api_client/models/term_variant_model.py b/mpt_api_client/models/term_variant_model.py
new file mode 100644
index 00000000..d3b598c0
--- /dev/null
+++ b/mpt_api_client/models/term_variant_model.py
@@ -0,0 +1,19 @@
+from mpt_api_client.models.file_resource_model import FileResourceModel
+
+
+class TermVariantModel(FileResourceModel):
+    """Base model for term variant resources.
+
+    Attributes:
+        asset_url: URL to the variant asset.
+        language_code: Language code for this variant.
+        status: Variant status.
+        filename: Original file name.
+        file_id: Identifier of the uploaded file.
+    """
+
+    asset_url: str | None = None
+    language_code: str | None = None
+    status: str | None = None
+    filename: str | None = None
+    file_id: str | None = None
diff --git a/mpt_api_client/resources/billing/credit_memo_attachments.py b/mpt_api_client/resources/billing/credit_memo_attachments.py
index ed194f90..cfd5bd7e 100644
--- a/mpt_api_client/resources/billing/credit_memo_attachments.py
+++ b/mpt_api_client/resources/billing/credit_memo_attachments.py
@@ -3,12 +3,12 @@
     AsyncCollectionMixin,
     CollectionMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import AttachmentModel
 from mpt_api_client.resources.billing.mixins import AsyncAttachmentMixin, AttachmentMixin
 
 
-class CreditMemoAttachment(Model):
-    """Credit Memo Attachment resource."""
+class CreditMemoAttachment(AttachmentModel):
+    """Credit Memo Attachment resource. Inherits fields from AttachmentModel."""
 
 
 class CreditMemoAttachmentsServiceConfig:
diff --git a/mpt_api_client/resources/billing/custom_ledger_attachments.py b/mpt_api_client/resources/billing/custom_ledger_attachments.py
index 59d42389..e9549f42 100644
--- a/mpt_api_client/resources/billing/custom_ledger_attachments.py
+++ b/mpt_api_client/resources/billing/custom_ledger_attachments.py
@@ -3,12 +3,12 @@
     AsyncCollectionMixin,
     CollectionMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import AttachmentModel
 from mpt_api_client.resources.billing.mixins import AsyncAttachmentMixin, AttachmentMixin
 
 
-class CustomLedgerAttachment(Model):
-    """Custom Ledger Attachment resource."""
+class CustomLedgerAttachment(AttachmentModel):
+    """Custom Ledger Attachment resource. Inherits fields from AttachmentModel."""
 
 
 class CustomLedgerAttachmentsServiceConfig:
diff --git a/mpt_api_client/resources/billing/invoice_attachments.py b/mpt_api_client/resources/billing/invoice_attachments.py
index 49650037..bb19dc6f 100644
--- a/mpt_api_client/resources/billing/invoice_attachments.py
+++ b/mpt_api_client/resources/billing/invoice_attachments.py
@@ -3,12 +3,12 @@
     AsyncCollectionMixin,
     CollectionMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import AttachmentModel
 from mpt_api_client.resources.billing.mixins import AsyncAttachmentMixin, AttachmentMixin
 
 
-class InvoiceAttachment(Model):
-    """Invoice Attachment resource."""
+class InvoiceAttachment(AttachmentModel):
+    """Invoice Attachment resource. Inherits fields from AttachmentModel."""
 
 
 class InvoiceAttachmentsServiceConfig:
diff --git a/mpt_api_client/resources/billing/journal_attachments.py b/mpt_api_client/resources/billing/journal_attachments.py
index e1ebafd6..8af263df 100644
--- a/mpt_api_client/resources/billing/journal_attachments.py
+++ b/mpt_api_client/resources/billing/journal_attachments.py
@@ -3,12 +3,12 @@
     AsyncCollectionMixin,
     CollectionMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import AttachmentModel
 from mpt_api_client.resources.billing.mixins import AsyncAttachmentMixin, AttachmentMixin
 
 
-class JournalAttachment(Model):
-    """Journal Attachment resource."""
+class JournalAttachment(AttachmentModel):
+    """Journal Attachment resource. Inherits fields from AttachmentModel."""
 
 
 class JournalAttachmentsServiceConfig:
diff --git a/mpt_api_client/resources/billing/ledger_attachments.py b/mpt_api_client/resources/billing/ledger_attachments.py
index e88144c5..46eba03b 100644
--- a/mpt_api_client/resources/billing/ledger_attachments.py
+++ b/mpt_api_client/resources/billing/ledger_attachments.py
@@ -3,12 +3,12 @@
     AsyncCollectionMixin,
     CollectionMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import AttachmentModel
 from mpt_api_client.resources.billing.mixins import AsyncAttachmentMixin, AttachmentMixin
 
 
-class LedgerAttachment(Model):
-    """Ledger Attachment resource."""
+class LedgerAttachment(AttachmentModel):
+    """Ledger Attachment resource. Inherits fields from AttachmentModel."""
 
 
 class LedgerAttachmentsServiceConfig:
diff --git a/mpt_api_client/resources/billing/statement_attachments.py b/mpt_api_client/resources/billing/statement_attachments.py
index c3ab9dae..f2c13fb7 100644
--- a/mpt_api_client/resources/billing/statement_attachments.py
+++ b/mpt_api_client/resources/billing/statement_attachments.py
@@ -3,12 +3,12 @@
     AsyncCollectionMixin,
     CollectionMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import AttachmentModel
 from mpt_api_client.resources.billing.mixins import AsyncAttachmentMixin, AttachmentMixin
 
 
-class StatementAttachment(Model):
-    """Statement Attachment resource."""
+class StatementAttachment(AttachmentModel):
+    """Statement Attachment resource. Inherits fields from AttachmentModel."""
 
 
 class StatementAttachmentsServiceConfig:
diff --git a/mpt_api_client/resources/catalog/pricing_policy_attachments.py b/mpt_api_client/resources/catalog/pricing_policy_attachments.py
index c414b3c7..18d0d2ae 100644
--- a/mpt_api_client/resources/catalog/pricing_policy_attachments.py
+++ b/mpt_api_client/resources/catalog/pricing_policy_attachments.py
@@ -9,32 +9,22 @@
     DownloadFileMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import AttachmentModel
 from mpt_api_client.models.model import BaseModel
 
 
-class PricingPolicyAttachment(Model):
+class PricingPolicyAttachment(AttachmentModel):
     """Pricing Policy Attachment resource.
 
     Attributes:
-        name: Attachment name.
-        type: Attachment type.
-        size: File size in bytes.
-        description: Attachment description.
         file_name: Original file name.
-        content_type: MIME content type of the attachment.
         status: Attachment status.
         audit: Audit information (created, updated events).
     """
 
-    name: str | None
-    type: str | None
-    size: int | None
-    description: str | None
-    file_name: str | None
-    content_type: str | None
-    status: str | None
-    audit: BaseModel | None
+    file_name: str | None = None
+    status: str | None = None
+    audit: BaseModel | None = None
 
 
 class PricingPolicyAttachmentsServiceConfig:
diff --git a/mpt_api_client/resources/catalog/product_term_variants.py b/mpt_api_client/resources/catalog/product_term_variants.py
index caa4e0e0..831bb489 100644
--- a/mpt_api_client/resources/catalog/product_term_variants.py
+++ b/mpt_api_client/resources/catalog/product_term_variants.py
@@ -9,7 +9,7 @@
     DownloadFileMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import TermVariantModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.mixins import (
     AsyncPublishableMixin,
@@ -19,36 +19,16 @@
 )
 
 
-class TermVariant(Model):
+class TermVariant(TermVariantModel):
     """Term variant resource.
 
     Attributes:
-        type: Variant type.
-        asset_url: URL to the term variant asset.
-        language_code: Language code for this variant.
-        name: Variant name.
-        description: Variant description.
-        status: Variant status.
-        filename: Original file name.
-        size: File size in bytes.
-        content_type: MIME content type of the file.
         terms_and_conditions: Reference to the parent terms and conditions.
-        file_id: Identifier of the uploaded file.
         audit: Audit information (created, updated events).
     """
 
-    type: str | None
-    asset_url: str | None
-    language_code: str | None
-    name: str | None
-    description: str | None
-    status: str | None
-    filename: str | None
-    size: int | None
-    content_type: str | None
-    terms_and_conditions: BaseModel | None
-    file_id: str | None
-    audit: BaseModel | None
+    terms_and_conditions: BaseModel | None = None
+    audit: BaseModel | None = None
 
 
 class TermVariantServiceConfig:
diff --git a/mpt_api_client/resources/catalog/products_documents.py b/mpt_api_client/resources/catalog/products_documents.py
index adf2b7ea..54645268 100644
--- a/mpt_api_client/resources/catalog/products_documents.py
+++ b/mpt_api_client/resources/catalog/products_documents.py
@@ -5,7 +5,7 @@
     CollectionMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import DocumentModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.mixins import (
     AsyncDocumentMixin,
@@ -15,34 +15,18 @@
 )
 
 
-class Document(Model):
+class Document(DocumentModel):
     """Document resource.
 
     Attributes:
-        name: Document name.
-        type: Document type.
-        description: Document description.
-        status: Document status.
-        filename: Original file name.
-        size: File size in bytes.
-        content_type: MIME content type of the document.
-        url: URL to access the document.
         language: Language code of the document.
         product: Reference to the product.
         audit: Audit information (created, updated events).
     """
 
-    name: str | None
-    type: str | None
-    description: str | None
-    status: str | None
-    filename: str | None
-    size: int | None
-    content_type: str | None
-    url: str | None
-    language: str | None
-    product: BaseModel | None
-    audit: BaseModel | None
+    language: str | None = None
+    product: BaseModel | None = None
+    audit: BaseModel | None = None
 
 
 class DocumentServiceConfig:
diff --git a/mpt_api_client/resources/catalog/products_media.py b/mpt_api_client/resources/catalog/products_media.py
index 39993098..f57234c9 100644
--- a/mpt_api_client/resources/catalog/products_media.py
+++ b/mpt_api_client/resources/catalog/products_media.py
@@ -5,7 +5,7 @@
     CollectionMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import MediaModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.mixins import (
     AsyncMediaMixin,
@@ -15,34 +15,16 @@
 )
 
 
-class Media(Model):
+class Media(MediaModel):
     """Media resource.
 
     Attributes:
-        name: Media name.
-        type: Media type.
-        description: Media description.
-        status: Media status.
-        filename: Original file name.
-        size: File size in bytes.
-        content_type: MIME content type of the media file.
-        display_order: Display order of the media item.
-        url: URL to access the media file.
         product: Reference to the product.
         audit: Audit information (created, updated events).
     """
 
-    name: str | None
-    type: str | None
-    description: str | None
-    status: str | None
-    filename: str | None
-    size: int | None
-    content_type: str | None
-    display_order: int | None
-    url: str | None
-    product: BaseModel | None
-    audit: BaseModel | None
+    product: BaseModel | None = None
+    audit: BaseModel | None = None
 
 
 class MediaServiceConfig:
diff --git a/mpt_api_client/resources/helpdesk/chat_attachments.py b/mpt_api_client/resources/helpdesk/chat_attachments.py
index f5e6c78f..4493c84f 100644
--- a/mpt_api_client/resources/helpdesk/chat_attachments.py
+++ b/mpt_api_client/resources/helpdesk/chat_attachments.py
@@ -1,42 +1,38 @@
 from mpt_api_client.http import AsyncService, Service, mixins
-from mpt_api_client.models import Model
-
-
-class ChatAttachment(Model):
-    """Helpdesk Chat Attachment resource."""
+from mpt_api_client.models import AttachmentModel
 
 
 class ChatAttachmentsServiceConfig:
     """Helpdesk Chat Attachments service configuration."""
 
     _endpoint = "/public/v1/helpdesk/chats/{chat_id}/attachments"
-    _model_class = ChatAttachment
+    _model_class = AttachmentModel
     _collection_key = "data"
     _upload_file_key = "file"
     _upload_data_key = "attachment"
 
 
 class ChatAttachmentsService(
-    mixins.CreateFileMixin[ChatAttachment],
-    mixins.UpdateMixin[ChatAttachment],
-    mixins.DownloadFileMixin[ChatAttachment],
+    mixins.CreateFileMixin[AttachmentModel],
+    mixins.UpdateMixin[AttachmentModel],
+    mixins.DownloadFileMixin[AttachmentModel],
     mixins.DeleteMixin,
-    mixins.GetMixin[ChatAttachment],
-    mixins.CollectionMixin[ChatAttachment],
-    Service[ChatAttachment],
+    mixins.GetMixin[AttachmentModel],
+    mixins.CollectionMixin[AttachmentModel],
+    Service[AttachmentModel],
     ChatAttachmentsServiceConfig,
 ):
     """Helpdesk Chat Attachments service."""
 
 
 class AsyncChatAttachmentsService(
-    mixins.AsyncCreateFileMixin[ChatAttachment],
-    mixins.AsyncUpdateMixin[ChatAttachment],
-    mixins.AsyncDownloadFileMixin[ChatAttachment],
+    mixins.AsyncCreateFileMixin[AttachmentModel],
+    mixins.AsyncUpdateMixin[AttachmentModel],
+    mixins.AsyncDownloadFileMixin[AttachmentModel],
     mixins.AsyncDeleteMixin,
-    mixins.AsyncGetMixin[ChatAttachment],
-    mixins.AsyncCollectionMixin[ChatAttachment],
-    AsyncService[ChatAttachment],
+    mixins.AsyncGetMixin[AttachmentModel],
+    mixins.AsyncCollectionMixin[AttachmentModel],
+    AsyncService[AttachmentModel],
     ChatAttachmentsServiceConfig,
 ):
     """Async Helpdesk Chat Attachments service."""
diff --git a/mpt_api_client/resources/integration/extension_documents.py b/mpt_api_client/resources/integration/extension_documents.py
index 96931a67..dc95d884 100644
--- a/mpt_api_client/resources/integration/extension_documents.py
+++ b/mpt_api_client/resources/integration/extension_documents.py
@@ -9,41 +9,25 @@
     DownloadFileMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import DocumentModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.mixins import AsyncPublishableMixin, PublishableMixin
 
 
-class ExtensionDocument(Model):
+class ExtensionDocument(DocumentModel):
     """Extension Document resource.
 
     Attributes:
-        name: Document name.
         revision: Revision number.
-        type: Document type (Online or File).
-        description: Document description.
-        status: Document status (Draft, Published, Unpublished, Deleted).
-        filename: Original file name.
-        size: File size in bytes.
-        content_type: MIME content type.
-        url: URL to access the document.
         language: Language code.
         extension: Reference to the extension.
         audit: Audit information (created, updated, published, unpublished).
     """
 
-    name: str | None
-    revision: int | None
-    type: str | None
-    description: str | None
-    status: str | None
-    filename: str | None
-    size: int | None
-    content_type: str | None
-    url: str | None
-    language: str | None
-    extension: BaseModel | None
-    audit: BaseModel | None
+    revision: int | None = None
+    language: str | None = None
+    extension: BaseModel | None = None
+    audit: BaseModel | None = None
 
 
 class ExtensionDocumentsServiceConfig:
diff --git a/mpt_api_client/resources/integration/extension_media.py b/mpt_api_client/resources/integration/extension_media.py
index 5f304bfb..1ec2812e 100644
--- a/mpt_api_client/resources/integration/extension_media.py
+++ b/mpt_api_client/resources/integration/extension_media.py
@@ -11,42 +11,24 @@
     DownloadFileMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import MediaModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.integration.mixins import AsyncMediaMixin, MediaMixin
 from mpt_api_client.resources.mixins import AsyncPublishableMixin, PublishableMixin
 
 
-class ExtensionMedia(Model):
+class ExtensionMedia(MediaModel):
     """Extension Media resource.
 
     Attributes:
-        name: Media name.
         revision: Revision number.
-        type: Media type (Video or Image).
-        description: Media description.
-        status: Media status (Draft, Published, Unpublished, Deleted).
-        filename: Original file name.
-        size: File size in bytes.
-        content_type: MIME content type.
-        display_order: Display order.
-        url: URL to access the media.
         extension: Reference to the extension.
         audit: Audit information (created, updated, published, unpublished).
     """
 
-    name: str | None
-    revision: int | None
-    type: str | None
-    description: str | None
-    status: str | None
-    filename: str | None
-    size: int | None
-    content_type: str | None
-    display_order: int | None
-    url: str | None
-    extension: BaseModel | None
-    audit: BaseModel | None
+    revision: int | None = None
+    extension: BaseModel | None = None
+    audit: BaseModel | None = None
 
 
 class ExtensionMediaServiceConfig:
diff --git a/mpt_api_client/resources/integration/extension_term_variants.py b/mpt_api_client/resources/integration/extension_term_variants.py
index 3e2be48f..96a1b5f3 100644
--- a/mpt_api_client/resources/integration/extension_term_variants.py
+++ b/mpt_api_client/resources/integration/extension_term_variants.py
@@ -7,7 +7,7 @@
     CreateFileMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import TermVariantModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.mixins import (
     AsyncPublishableMixin,
@@ -15,38 +15,18 @@
 )
 
 
-class ExtensionTermVariant(Model):
+class ExtensionTermVariant(TermVariantModel):
     """Extension Term Variant resource.
 
     Attributes:
-        name: Variant name.
         revision: Revision number.
-        type: Variant type (Online or File).
-        asset_url: URL to the variant asset for Online type.
-        language_code: Language code for this variant.
-        description: Variant description.
-        status: Variant status (Draft, Published, Unpublished, Deleted).
-        filename: Original file name for File type.
-        size: File size in bytes for File type.
-        content_type: MIME content type of the file.
         term: Reference to the parent term.
-        file_id: Identifier of the uploaded file.
         audit: Audit information (created, updated, published, unpublished).
     """
 
-    name: str | None
-    revision: int | None
-    type: str | None
-    asset_url: str | None
-    language_code: str | None
-    description: str | None
-    status: str | None
-    filename: str | None
-    size: int | None
-    content_type: str | None
-    term: BaseModel | None
-    file_id: str | None
-    audit: BaseModel | None
+    revision: int | None = None
+    term: BaseModel | None = None
+    audit: BaseModel | None = None
 
 
 class ExtensionTermVariantsServiceConfig:
diff --git a/mpt_api_client/resources/program/enrollments_attachments.py b/mpt_api_client/resources/program/enrollments_attachments.py
index e285b83a..6ade868b 100644
--- a/mpt_api_client/resources/program/enrollments_attachments.py
+++ b/mpt_api_client/resources/program/enrollments_attachments.py
@@ -3,31 +3,21 @@
     AsyncCollectionMixin,
     CollectionMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import AttachmentModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.mixins.attachment_mixin import AsyncAttachmentMixin, AttachmentMixin
 
 
-class EnrollmentAttachment(Model):
+class EnrollmentAttachment(AttachmentModel):
     """Enrollment Attachment resource.
 
     Attributes:
-        name: The name of the attachment.
-        description: The description of the attachment.
-        type: The type of the attachment.
         filename: The filename of the attachment.
-        size: The size of the attachment in bytes.
-        content_type: The content type of the attachment.
         enrollment: The enrollment associated with the attachment.
         audit: The audit information for the attachment.
     """
 
-    name: str | None = None
-    description: str | None = None
-    type: str | None = None
     filename: str | None = None
-    size: int | None = None
-    content_type: str | None = None
     enrollment: BaseModel | None = None
     audit: BaseModel | None = None
 
diff --git a/mpt_api_client/resources/program/programs_documents.py b/mpt_api_client/resources/program/programs_documents.py
index a434a1d5..488272cb 100644
--- a/mpt_api_client/resources/program/programs_documents.py
+++ b/mpt_api_client/resources/program/programs_documents.py
@@ -5,37 +5,21 @@
     CollectionMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import DocumentModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.mixins import AsyncDocumentMixin, DocumentMixin
 
 
-class Document(Model):
+class Document(DocumentModel):
     """Document resource.
 
     Attributes:
-        name: Document name.
-        type: Document type.
-        description: Document description.
-        status: Document status.
-        filename: Original file name.
-        size: File size in bytes.
-        content_type: MIME content type of the document.
-        url: URL to access the document.
         program: Reference to the program.
         audit: Audit information (created, updated events).
     """
 
-    name: str | None
-    type: str | None
-    description: str | None
-    status: str | None
-    filename: str | None
-    size: int | None
-    content_type: str | None
-    url: str | None
-    program: BaseModel | None
-    audit: BaseModel | None
+    program: BaseModel | None = None
+    audit: BaseModel | None = None
 
 
 class DocumentServiceConfig:
diff --git a/mpt_api_client/resources/program/programs_media.py b/mpt_api_client/resources/program/programs_media.py
index ad8e9c10..5dfb25b1 100644
--- a/mpt_api_client/resources/program/programs_media.py
+++ b/mpt_api_client/resources/program/programs_media.py
@@ -5,39 +5,21 @@
     CollectionMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import MediaModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.mixins import AsyncMediaMixin, MediaMixin
 
 
-class Media(Model):
+class Media(MediaModel):
     """Media resource.
 
     Attributes:
-        name: Media name.
-        type: Media type.
-        description: Media description.
-        status: Media status.
-        filename: Original file name.
-        size: File size in bytes.
-        content_type: MIME content type of the media file.
-        display_order: Display order of the media item.
-        url: URL to access the media file.
         program: Reference to the program.
         audit: Audit information (created, updated events).
     """
 
-    name: str | None
-    type: str | None
-    description: str | None
-    status: str | None
-    filename: str | None
-    size: int | None
-    content_type: str | None
-    display_order: int | None
-    url: str | None
-    program: BaseModel | None
-    audit: BaseModel | None
+    program: BaseModel | None = None
+    audit: BaseModel | None = None
 
 
 class MediaServiceConfig:
diff --git a/mpt_api_client/resources/program/programs_terms_variant.py b/mpt_api_client/resources/program/programs_terms_variant.py
index f826b3e7..5f2d80f2 100644
--- a/mpt_api_client/resources/program/programs_terms_variant.py
+++ b/mpt_api_client/resources/program/programs_terms_variant.py
@@ -9,41 +9,21 @@
     DownloadFileMixin,
     ModifiableResourceMixin,
 )
-from mpt_api_client.models import Model
+from mpt_api_client.models import TermVariantModel
 from mpt_api_client.models.model import BaseModel
 from mpt_api_client.resources.mixins import AsyncPublishableMixin, PublishableMixin
 
 
-class TermVariant(Model):
+class TermVariant(TermVariantModel):
     """Term variant resource.
 
     Attributes:
-        name: The name of the term variant.
-        type: The type of the term variant.
-        asset_url: The URL of the asset.
-        language_code: The language code of the term variant.
-        description: The description of the term variant.
-        status: The status of the term variant.
-        filename: The filename of the term variant.
-        size: The size of the term variant.
-        content_type: The content type of the term variant.
         program_terms_and_conditions: The associated program terms and conditions.
-        file_id: The ID of the file.
         audit: The audit information.
     """
 
-    name: str | None
-    type: str | None
-    asset_url: str | None
-    language_code: str | None
-    description: str | None
-    status: str | None
-    filename: str | None
-    size: int | None
-    content_type: str | None
-    program_terms_and_conditions: BaseModel | None
-    file_id: str | None
-    audit: BaseModel | None
+    program_terms_and_conditions: BaseModel | None = None
+    audit: BaseModel | None = None
 
 
 class TermVariantServiceConfig:
diff --git a/tests/e2e/helpdesk/chats/attachment/test_async_attachment.py b/tests/e2e/helpdesk/chats/attachment/test_async_attachment.py
index f9fa6169..3cc25bca 100644
--- a/tests/e2e/helpdesk/chats/attachment/test_async_attachment.py
+++ b/tests/e2e/helpdesk/chats/attachment/test_async_attachment.py
@@ -3,7 +3,7 @@
 import pytest
 
 from mpt_api_client.exceptions import MPTAPIError
-from mpt_api_client.resources.helpdesk.chat_attachments import ChatAttachment
+from mpt_api_client.models import AttachmentModel
 
 pytestmark = [pytest.mark.flaky]
 
@@ -12,18 +12,18 @@ async def test_list_chat_attachments(async_chat_attachments_service, async_creat
     result = await async_chat_attachments_service.fetch_page(limit=1)
 
     assert len(result) > 0
-    assert all(isinstance(attachment, ChatAttachment) for attachment in result)
+    assert all(isinstance(attachment, AttachmentModel) for attachment in result)
 
 
 def test_create_chat_attachment(async_created_chat_attachment, chat_attachment_data):  # noqa: AAA01
-    assert isinstance(async_created_chat_attachment, ChatAttachment)
+    assert isinstance(async_created_chat_attachment, AttachmentModel)
     assert async_created_chat_attachment.to_dict().get("name") == chat_attachment_data["name"]
 
 
 async def test_get_chat_attachment(async_chat_attachments_service, async_created_chat_attachment):
     result = await async_chat_attachments_service.get(async_created_chat_attachment.id)
 
-    assert isinstance(result, ChatAttachment)
+    assert isinstance(result, AttachmentModel)
 
 
 async def test_update_chat_attachment(
@@ -36,7 +36,7 @@ async def test_update_chat_attachment(
         {"name": updated_name, "description": updated_name},
     )
 
-    assert isinstance(result, ChatAttachment)
+    assert isinstance(result, AttachmentModel)
     assert result.to_dict().get("name") == updated_name
 
 
diff --git a/tests/e2e/helpdesk/chats/attachment/test_sync_attachment.py b/tests/e2e/helpdesk/chats/attachment/test_sync_attachment.py
index 22b18dd3..63ebc9a4 100644
--- a/tests/e2e/helpdesk/chats/attachment/test_sync_attachment.py
+++ b/tests/e2e/helpdesk/chats/attachment/test_sync_attachment.py
@@ -3,7 +3,7 @@
 import pytest
 
 from mpt_api_client.exceptions import MPTAPIError
-from mpt_api_client.resources.helpdesk.chat_attachments import ChatAttachment
+from mpt_api_client.models import AttachmentModel
 
 pytestmark = [pytest.mark.flaky]
 
@@ -12,18 +12,18 @@ def test_list_chat_attachments(chat_attachments_service, created_chat_attachment
     result = chat_attachments_service.fetch_page(limit=1)
 
     assert len(result) > 0
-    assert all(isinstance(attachment, ChatAttachment) for attachment in result)
+    assert all(isinstance(attachment, AttachmentModel) for attachment in result)
 
 
 def test_create_chat_attachment(created_chat_attachment, chat_attachment_data):  # noqa: AAA01
-    assert isinstance(created_chat_attachment, ChatAttachment)
+    assert isinstance(created_chat_attachment, AttachmentModel)
     assert created_chat_attachment.to_dict().get("name") == chat_attachment_data["name"]
 
 
 def test_get_chat_attachment(chat_attachments_service, created_chat_attachment):
     result = chat_attachments_service.get(created_chat_attachment.id)
 
-    assert isinstance(result, ChatAttachment)
+    assert isinstance(result, AttachmentModel)
 
 
 def test_update_chat_attachment(chat_attachments_service, created_chat_attachment, short_uuid):
@@ -34,7 +34,7 @@ def test_update_chat_attachment(chat_attachments_service, created_chat_attachmen
         {"name": updated_name, "description": updated_name},
     )
 
-    assert isinstance(result, ChatAttachment)
+    assert isinstance(result, AttachmentModel)
     assert result.to_dict().get("name") == updated_name
 
 
diff --git a/tests/unit/conftest.py b/tests/unit/conftest.py
index 07a2845b..df76d043 100644
--- a/tests/unit/conftest.py
+++ b/tests/unit/conftest.py
@@ -19,3 +19,63 @@ def http_client():
 @pytest.fixture
 def async_http_client():
     return AsyncHTTPClient(base_url=API_URL, api_token=API_TOKEN)
+
+
+@pytest.fixture
+def attachment_data():
+    return {
+        "id": "ATT-001",
+        "name": "attachment.pdf",
+        "type": "Document",
+        "size": 2048,
+        "description": "Attachment description",
+        "contentType": "application/pdf",
+    }
+
+
+@pytest.fixture
+def document_inherited_data():
+    return {
+        "id": "DOC-001",
+        "name": "User Guide",
+        "type": "Document",
+        "description": "User guide document",
+        "status": "Active",
+        "filename": "guide.pdf",
+        "size": 4096,
+        "contentType": "application/pdf",
+        "url": "https://example.com/guide.pdf",
+    }
+
+
+@pytest.fixture
+def media_inherited_data():
+    return {
+        "id": "MED-001",
+        "name": "Screenshot",
+        "type": "Image",
+        "description": "Product screenshot",
+        "status": "Active",
+        "filename": "screenshot.png",
+        "size": 512000,
+        "contentType": "image/png",
+        "displayOrder": 1,
+        "url": "https://example.com/screenshot.png",
+    }
+
+
+@pytest.fixture
+def term_variant_inherited_data():
+    return {
+        "id": "TRV-001",
+        "name": "English Variant",
+        "type": "PDF",
+        "assetUrl": "https://example.com/file.pdf",
+        "languageCode": "en-US",
+        "description": "English language variant",
+        "status": "Active",
+        "filename": "terms.pdf",
+        "size": 2048,
+        "contentType": "application/pdf",
+        "fileId": "FILE-001",
+    }
diff --git a/tests/unit/models/test_attachment_model.py b/tests/unit/models/test_attachment_model.py
new file mode 100644
index 00000000..e8468d65
--- /dev/null
+++ b/tests/unit/models/test_attachment_model.py
@@ -0,0 +1,42 @@
+from mpt_api_client.models import AttachmentModel
+
+
+class AttachmentModelDummy(AttachmentModel):
+    """Dummy class for testing AttachmentModel."""
+
+
+def test_attachment_absent_fields():  # noqa: WPS218
+    result = AttachmentModelDummy({"id": "ATT-001"})
+
+    assert result.id == "ATT-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
+
+
+def test_attachment_populates_camel():  # noqa: WPS218
+    resource_data = {
+        "id": "ATT-001",
+        "name": "doc.pdf",
+        "type": "application/pdf",
+        "size": 1024,
+        "description": "A document",
+        "contentType": "application/pdf",
+    }
+
+    result = AttachmentModelDummy(resource_data)
+
+    assert result.name == "doc.pdf"
+    assert result.type == "application/pdf"
+    assert result.size == 1024
+    assert result.description == "A document"
+    assert result.content_type == "application/pdf"
+    assert result.to_dict() == resource_data
+
+
+def test_attachment_repr():
+    result = AttachmentModelDummy({"id": "ATT-001"})
+
+    assert repr(result) == "<AttachmentModelDummy ATT-001>"
diff --git a/tests/unit/models/test_document_model.py b/tests/unit/models/test_document_model.py
new file mode 100644
index 00000000..20a8a50f
--- /dev/null
+++ b/tests/unit/models/test_document_model.py
@@ -0,0 +1,47 @@
+from mpt_api_client.models import DocumentModel
+
+
+class DocumentModelDummy(DocumentModel):
+    """Dummy class for testing DocumentModel."""
+
+
+def test_document_absent_fields():  # noqa: WPS218
+    result = DocumentModelDummy({"id": "DOC-001"})
+
+    assert result.id == "DOC-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.url is None
+
+
+def test_document_populates_camel():
+    resource_data = {
+        "id": "DOC-001",
+        "name": "User Guide",
+        "type": "Document",
+        "size": 4096,
+        "description": "User guide document",
+        "contentType": "application/pdf",
+        "status": "Active",
+        "filename": "guide.pdf",
+        "url": "https://example.com/guide.pdf",
+    }
+
+    result = DocumentModelDummy(resource_data)
+
+    assert result.name == "User Guide"
+    assert result.status == "Active"
+    assert result.filename == "guide.pdf"
+    assert result.url == "https://example.com/guide.pdf"
+    assert result.to_dict() == resource_data
+
+
+def test_document_repr():
+    result = DocumentModelDummy({"id": "DOC-001"})
+
+    assert repr(result) == "<DocumentModelDummy DOC-001>"
diff --git a/tests/unit/models/test_file_resource_model.py b/tests/unit/models/test_file_resource_model.py
new file mode 100644
index 00000000..1286ffe2
--- /dev/null
+++ b/tests/unit/models/test_file_resource_model.py
@@ -0,0 +1,42 @@
+from mpt_api_client.models import FileResourceModel
+
+
+class FileResourceModelDummy(FileResourceModel):
+    """Dummy class for testing FileResourceModel."""
+
+
+def test_file_resource_absent_fields():  # noqa: WPS218
+    result = FileResourceModelDummy({"id": "FRM-001"})
+
+    assert result.id == "FRM-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
+
+
+def test_file_resource_populates_camel():  # noqa: WPS218
+    resource_data = {
+        "id": "FRM-001",
+        "name": "file.pdf",
+        "type": "Document",
+        "size": 1024,
+        "description": "A file",
+        "contentType": "application/pdf",
+    }
+
+    result = FileResourceModelDummy(resource_data)
+
+    assert result.name == "file.pdf"
+    assert result.type == "Document"
+    assert result.size == 1024
+    assert result.description == "A file"
+    assert result.content_type == "application/pdf"
+    assert result.to_dict() == resource_data
+
+
+def test_file_resource_repr():
+    result = FileResourceModelDummy({"id": "FRM-001"})
+
+    assert repr(result) == "<FileResourceModelDummy FRM-001>"
diff --git a/tests/unit/models/test_media_model.py b/tests/unit/models/test_media_model.py
new file mode 100644
index 00000000..96c7f79c
--- /dev/null
+++ b/tests/unit/models/test_media_model.py
@@ -0,0 +1,49 @@
+from mpt_api_client.models import MediaModel
+
+
+class MediaModelDummy(MediaModel):
+    """Dummy class for testing MediaModel."""
+
+
+def test_media_absent_fields():  # noqa: WPS218
+    result = MediaModelDummy({"id": "MED-001"})
+
+    assert result.id == "MED-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.display_order is None
+    assert result.url is None
+
+
+def test_media_populates_camel():
+    resource_data = {
+        "id": "MED-001",
+        "name": "Screenshot",
+        "type": "Image",
+        "size": 512000,
+        "description": "Product screenshot",
+        "contentType": "image/png",
+        "status": "Active",
+        "filename": "screenshot.png",
+        "displayOrder": 1,
+        "url": "https://example.com/screenshot.png",
+    }
+
+    result = MediaModelDummy(resource_data)
+
+    assert result.name == "Screenshot"
+    assert result.status == "Active"
+    assert result.display_order == 1
+    assert result.url == "https://example.com/screenshot.png"
+    assert result.to_dict() == resource_data
+
+
+def test_media_repr():
+    result = MediaModelDummy({"id": "MED-001"})
+
+    assert repr(result) == "<MediaModelDummy MED-001>"
diff --git a/tests/unit/models/test_term_variant_model.py b/tests/unit/models/test_term_variant_model.py
new file mode 100644
index 00000000..075f297b
--- /dev/null
+++ b/tests/unit/models/test_term_variant_model.py
@@ -0,0 +1,51 @@
+from mpt_api_client.models import TermVariantModel
+
+
+class TermVariantModelDummy(TermVariantModel):
+    """Dummy class for testing TermVariantModel."""
+
+
+def test_term_variant_absent_fields():  # noqa: WPS218
+    result = TermVariantModelDummy({"id": "TRV-001"})
+
+    assert result.id == "TRV-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
+    assert result.asset_url is None
+    assert result.language_code is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.file_id is None
+
+
+def test_term_variant_populates_camel():
+    resource_data = {
+        "id": "TRV-001",
+        "name": "English Variant",
+        "type": "PDF",
+        "size": 2048,
+        "description": "English language variant",
+        "contentType": "application/pdf",
+        "assetUrl": "https://example.com/file.pdf",
+        "languageCode": "en-US",
+        "status": "Active",
+        "filename": "terms.pdf",
+        "fileId": "FILE-001",
+    }
+
+    result = TermVariantModelDummy(resource_data)
+
+    assert result.name == "English Variant"
+    assert result.asset_url == "https://example.com/file.pdf"
+    assert result.language_code == "en-US"
+    assert result.file_id == "FILE-001"
+    assert result.to_dict() == resource_data
+
+
+def test_term_variant_repr():
+    result = TermVariantModelDummy({"id": "TRV-001"})
+
+    assert repr(result) == "<TermVariantModelDummy TRV-001>"
diff --git a/tests/unit/resources/billing/test_credit_memo_attachments.py b/tests/unit/resources/billing/test_credit_memo_attachments.py
index 56cc6fdd..661b78e9 100644
--- a/tests/unit/resources/billing/test_credit_memo_attachments.py
+++ b/tests/unit/resources/billing/test_credit_memo_attachments.py
@@ -2,6 +2,7 @@
 
 from mpt_api_client.resources.billing.credit_memo_attachments import (
     AsyncCreditMemoAttachmentsService,
+    CreditMemoAttachment,
     CreditMemoAttachmentsService,
 )
 
@@ -50,3 +51,20 @@ def test_async_methods_present(async_credit_memo_attachments_service, method: st
     result = hasattr(async_credit_memo_attachments_service, method)
 
     assert result is True
+
+
+def test_attachment_inherited_primitive_fields(attachment_data):
+    result = CreditMemoAttachment(attachment_data)
+
+    assert result.to_dict() == attachment_data
+
+
+def test_attachment_inherited_fields_absent():  # noqa: WPS218
+    result = CreditMemoAttachment({"id": "ATT-001"})
+
+    assert result.id == "ATT-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
diff --git a/tests/unit/resources/billing/test_custom_ledger_attachments.py b/tests/unit/resources/billing/test_custom_ledger_attachments.py
index 69b37ce8..2a29c793 100644
--- a/tests/unit/resources/billing/test_custom_ledger_attachments.py
+++ b/tests/unit/resources/billing/test_custom_ledger_attachments.py
@@ -2,6 +2,7 @@
 
 from mpt_api_client.resources.billing.custom_ledger_attachments import (
     AsyncCustomLedgerAttachmentsService,
+    CustomLedgerAttachment,
     CustomLedgerAttachmentsService,
 )
 
@@ -48,3 +49,20 @@ def test_async_methods_present(async_custom_ledger_attachments_service, method:
     result = hasattr(async_custom_ledger_attachments_service, method)
 
     assert result is True
+
+
+def test_attachment_inherited_primitive_fields(attachment_data):
+    result = CustomLedgerAttachment(attachment_data)
+
+    assert result.to_dict() == attachment_data
+
+
+def test_attachment_inherited_fields_absent():  # noqa: WPS218
+    result = CustomLedgerAttachment({"id": "ATT-001"})
+
+    assert result.id == "ATT-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
diff --git a/tests/unit/resources/billing/test_invoice_attachments.py b/tests/unit/resources/billing/test_invoice_attachments.py
index a43dc56f..15591a66 100644
--- a/tests/unit/resources/billing/test_invoice_attachments.py
+++ b/tests/unit/resources/billing/test_invoice_attachments.py
@@ -2,6 +2,7 @@
 
 from mpt_api_client.resources.billing.invoice_attachments import (
     AsyncInvoiceAttachmentsService,
+    InvoiceAttachment,
     InvoiceAttachmentsService,
 )
 
@@ -49,3 +50,20 @@ def test_async_methods_present(async_invoice_attachments_service, method: str):
     result = hasattr(async_invoice_attachments_service, method)
 
     assert result is True
+
+
+def test_attachment_inherited_primitive_fields(attachment_data):
+    result = InvoiceAttachment(attachment_data)
+
+    assert result.to_dict() == attachment_data
+
+
+def test_attachment_inherited_fields_absent():  # noqa: WPS218
+    result = InvoiceAttachment({"id": "ATT-001"})
+
+    assert result.id == "ATT-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
diff --git a/tests/unit/resources/billing/test_journal_attachments.py b/tests/unit/resources/billing/test_journal_attachments.py
index 86cdc1c7..89321aec 100644
--- a/tests/unit/resources/billing/test_journal_attachments.py
+++ b/tests/unit/resources/billing/test_journal_attachments.py
@@ -2,6 +2,7 @@
 
 from mpt_api_client.resources.billing.journal_attachments import (
     AsyncJournalAttachmentsService,
+    JournalAttachment,
     JournalAttachmentsService,
 )
 
@@ -49,3 +50,20 @@ def test_async_methods_present(async_journal_attachments_service, method: str) -
     result = hasattr(async_journal_attachments_service, method)
 
     assert result is True
+
+
+def test_attachment_inherited_primitive_fields(attachment_data):
+    result = JournalAttachment(attachment_data)
+
+    assert result.to_dict() == attachment_data
+
+
+def test_attachment_inherited_fields_absent():  # noqa: WPS218
+    result = JournalAttachment({"id": "ATT-001"})
+
+    assert result.id == "ATT-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
diff --git a/tests/unit/resources/billing/test_ledger_attachments.py b/tests/unit/resources/billing/test_ledger_attachments.py
index d4321c6d..55911edb 100644
--- a/tests/unit/resources/billing/test_ledger_attachments.py
+++ b/tests/unit/resources/billing/test_ledger_attachments.py
@@ -2,6 +2,7 @@
 
 from mpt_api_client.resources.billing.ledger_attachments import (
     AsyncLedgerAttachmentsService,
+    LedgerAttachment,
     LedgerAttachmentsService,
 )
 
@@ -49,3 +50,20 @@ def test_async_methods_present(async_ledger_attachments_service, method: str) ->
     result = hasattr(async_ledger_attachments_service, method)
 
     assert result is True
+
+
+def test_attachment_inherited_primitive_fields(attachment_data):
+    result = LedgerAttachment(attachment_data)
+
+    assert result.to_dict() == attachment_data
+
+
+def test_attachment_inherited_fields_absent():  # noqa: WPS218
+    result = LedgerAttachment({"id": "ATT-001"})
+
+    assert result.id == "ATT-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
diff --git a/tests/unit/resources/billing/test_statement_attachments.py b/tests/unit/resources/billing/test_statement_attachments.py
index be1573df..b177f339 100644
--- a/tests/unit/resources/billing/test_statement_attachments.py
+++ b/tests/unit/resources/billing/test_statement_attachments.py
@@ -2,6 +2,7 @@
 
 from mpt_api_client.resources.billing.statement_attachments import (
     AsyncStatementAttachmentsService,
+    StatementAttachment,
     StatementAttachmentsService,
 )
 
@@ -50,3 +51,20 @@ def test_async_methods_present(async_statement_attachments_service, method: str)
     result = hasattr(async_statement_attachments_service, method)
 
     assert result is True
+
+
+def test_attachment_inherited_primitive_fields(attachment_data):
+    result = StatementAttachment(attachment_data)
+
+    assert result.to_dict() == attachment_data
+
+
+def test_attachment_inherited_fields_absent():  # noqa: WPS218
+    result = StatementAttachment({"id": "ATT-001"})
+
+    assert result.id == "ATT-001"
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
diff --git a/tests/unit/resources/catalog/test_pricing_policy_attachments.py b/tests/unit/resources/catalog/test_pricing_policy_attachments.py
index ec923977..773e9dc6 100644
--- a/tests/unit/resources/catalog/test_pricing_policy_attachments.py
+++ b/tests/unit/resources/catalog/test_pricing_policy_attachments.py
@@ -83,10 +83,15 @@ def test_pricing_policy_attachment_nested_models(pricing_policy_attachment_data)
     assert isinstance(result.audit, BaseModel)
 
 
-def test_pricing_policy_attachment_absent():
+def test_pricing_policy_attachment_absent():  # noqa: WPS218
     result = PricingPolicyAttachment({"id": "ATT-001"})
 
     assert result.id == "ATT-001"
-    assert not hasattr(result, "name")
-    assert not hasattr(result, "status")
-    assert not hasattr(result, "audit")
+    assert result.name is None
+    assert result.type is None
+    assert result.size is None
+    assert result.description is None
+    assert result.content_type is None
+    assert result.file_name is None
+    assert result.status is None
+    assert result.audit is None
diff --git a/tests/unit/resources/catalog/test_product_term_variants.py b/tests/unit/resources/catalog/test_product_term_variants.py
index 940ff4f6..90020f90 100644
--- a/tests/unit/resources/catalog/test_product_term_variants.py
+++ b/tests/unit/resources/catalog/test_product_term_variants.py
@@ -89,6 +89,12 @@ def test_term_variant_primitive_fields(term_variant_data: dict) -> None:
     assert result.to_dict() == term_variant_data
 
 
+def test_term_variant_inherited_primitive_fields(term_variant_inherited_data: dict) -> None:
+    result = TermVariant(term_variant_inherited_data)
+
+    assert result.to_dict() == term_variant_inherited_data
+
+
 def test_term_variant_nested_base_models(term_variant_data: dict) -> None:
     result = TermVariant(term_variant_data)
 
@@ -96,10 +102,19 @@ def test_term_variant_nested_base_models(term_variant_data: dict) -> None:
     assert isinstance(result.audit, BaseModel)
 
 
-def test_term_variant_optional_fields_absent() -> None:
+def test_term_variant_optional_fields_absent() -> None:  # noqa: WPS218
     result = TermVariant({"id": "TRV-001"})
 
     assert result.id == "TRV-001"
-    assert not hasattr(result, "name")
-    assert not hasattr(result, "status")
-    assert not hasattr(result, "audit")
+    assert result.name is None
+    assert result.type is None
+    assert result.asset_url is None
+    assert result.language_code is None
+    assert result.description is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.size is None
+    assert result.content_type is None
+    assert result.file_id is None
+    assert result.terms_and_conditions is None
+    assert result.audit is None
diff --git a/tests/unit/resources/catalog/test_products_documents.py b/tests/unit/resources/catalog/test_products_documents.py
index af22ccfa..6180ae26 100644
--- a/tests/unit/resources/catalog/test_products_documents.py
+++ b/tests/unit/resources/catalog/test_products_documents.py
@@ -76,6 +76,12 @@ def test_document_primitive_fields(document_data):
     assert result.to_dict() == document_data
 
 
+def test_document_inherited_primitive_fields(document_inherited_data):
+    result = Document(document_inherited_data)
+
+    assert result.to_dict() == document_inherited_data
+
+
 def test_document_nested_fields_are_base_models(document_data):
     result = Document(document_data)
 
@@ -83,10 +89,18 @@ def test_document_nested_fields_are_base_models(document_data):
     assert isinstance(result.audit, BaseModel)
 
 
-def test_document_optional_fields_absent():
+def test_document_optional_fields_absent():  # noqa: WPS218
     result = Document({"id": "DOC-001"})
 
     assert result.id == "DOC-001"
-    assert not hasattr(result, "name")
-    assert not hasattr(result, "status")
-    assert not hasattr(result, "audit")
+    assert result.name is None
+    assert result.type is None
+    assert result.description is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.size is None
+    assert result.content_type is None
+    assert result.url is None
+    assert result.language is None
+    assert result.product is None
+    assert result.audit is None
diff --git a/tests/unit/resources/catalog/test_products_media.py b/tests/unit/resources/catalog/test_products_media.py
index bd789af9..565978eb 100644
--- a/tests/unit/resources/catalog/test_products_media.py
+++ b/tests/unit/resources/catalog/test_products_media.py
@@ -76,6 +76,12 @@ def test_media_primitive_fields(media_data):
     assert result.to_dict() == media_data
 
 
+def test_media_inherited_primitive_fields(media_inherited_data):
+    result = Media(media_inherited_data)
+
+    assert result.to_dict() == media_inherited_data
+
+
 def test_media_nested_fields_are_base_models(media_data):
     result = Media(media_data)
 
@@ -83,10 +89,18 @@ def test_media_nested_fields_are_base_models(media_data):
     assert isinstance(result.audit, BaseModel)
 
 
-def test_media_optional_fields_absent():
+def test_media_optional_fields_absent():  # noqa: WPS218
     result = Media({"id": "MED-001"})
 
     assert result.id == "MED-001"
-    assert not hasattr(result, "name")
-    assert not hasattr(result, "status")
-    assert not hasattr(result, "audit")
+    assert result.name is None
+    assert result.type is None
+    assert result.description is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.size is None
+    assert result.content_type is None
+    assert result.display_order is None
+    assert result.url is None
+    assert result.product is None
+    assert result.audit is None
diff --git a/tests/unit/resources/integration/test_extension_documents.py b/tests/unit/resources/integration/test_extension_documents.py
index bbef452a..8b8f50a8 100644
--- a/tests/unit/resources/integration/test_extension_documents.py
+++ b/tests/unit/resources/integration/test_extension_documents.py
@@ -100,6 +100,12 @@ def test_extension_document_primitive_fields(document_data):
     assert result.to_dict() == document_data
 
 
+def test_extension_document_inherited_fields(document_inherited_data):
+    result = ExtensionDocument(document_inherited_data)
+
+    assert result.to_dict() == document_inherited_data
+
+
 def test_extension_document_nested_fields(document_data):
     result = ExtensionDocument(document_data)
 
@@ -111,9 +117,18 @@ def test_extension_document_optional_absent():
     result = ExtensionDocument({"id": "DOC-001"})
 
     assert result.id == "DOC-001"
-    assert not hasattr(result, "name")
-    assert not hasattr(result, "status")
-    assert not hasattr(result, "audit")
+    assert result.name is None
+    assert result.type is None
+    assert result.description is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.size is None
+    assert result.content_type is None
+    assert result.url is None
+    assert result.revision is None
+    assert result.language is None
+    assert result.extension is None
+    assert result.audit is None
 
 
 def test_extension_document_create(extension_documents_service, tmp_path):
diff --git a/tests/unit/resources/integration/test_extension_media.py b/tests/unit/resources/integration/test_extension_media.py
index 55a39362..8df0d369 100644
--- a/tests/unit/resources/integration/test_extension_media.py
+++ b/tests/unit/resources/integration/test_extension_media.py
@@ -103,6 +103,12 @@ def test_extension_media_primitive_fields(media_data) -> None:
     assert result.display_order == 1
 
 
+def test_extension_media_inherited_fields(media_inherited_data) -> None:
+    result = ExtensionMedia(media_inherited_data)
+
+    assert result.to_dict() == media_inherited_data
+
+
 def test_extension_media_nested_fields(media_data) -> None:  # noqa: WPS118
     result = ExtensionMedia(media_data)
 
diff --git a/tests/unit/resources/integration/test_extension_term_variants.py b/tests/unit/resources/integration/test_extension_term_variants.py
index ea714c17..45df1de8 100644
--- a/tests/unit/resources/integration/test_extension_term_variants.py
+++ b/tests/unit/resources/integration/test_extension_term_variants.py
@@ -87,6 +87,14 @@ def test_extension_term_variant_primitive_fields(variant_data: dict) -> None:
     assert result.to_dict() == variant_data
 
 
+def test_extension_term_variant_inherited_fields(
+    term_variant_inherited_data: dict,
+) -> None:
+    result = ExtensionTermVariant(term_variant_inherited_data)
+
+    assert result.to_dict() == term_variant_inherited_data
+
+
 def test_extension_term_variant_nested_fields(variant_data: dict) -> None:
     result = ExtensionTermVariant(variant_data)
 
diff --git a/tests/unit/resources/program/test_programs_documents.py b/tests/unit/resources/program/test_programs_documents.py
index e49dd98a..b68f0070 100644
--- a/tests/unit/resources/program/test_programs_documents.py
+++ b/tests/unit/resources/program/test_programs_documents.py
@@ -76,6 +76,12 @@ def test_document_primitive_fields(document_data):
     assert result.to_dict() == document_data
 
 
+def test_document_inherited_primitive_fields(document_inherited_data):
+    result = Document(document_inherited_data)
+
+    assert result.to_dict() == document_inherited_data
+
+
 def test_document_nested_fields_are_base_models(document_data):
     result = Document(document_data)
 
@@ -87,8 +93,13 @@ def test_document_optional_fields_absent():
     result = Document({"id": "PDM-001"})
 
     assert result.id == "PDM-001"
-    assert not hasattr(result, "name")
-    assert not hasattr(result, "type")
-    assert not hasattr(result, "description")
-    assert not hasattr(result, "status")
-    assert not hasattr(result, "audit")
+    assert result.name is None
+    assert result.type is None
+    assert result.description is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.size is None
+    assert result.content_type is None
+    assert result.url is None
+    assert result.program is None
+    assert result.audit is None
diff --git a/tests/unit/resources/program/test_programs_media.py b/tests/unit/resources/program/test_programs_media.py
index 3dbe0d45..24229915 100644
--- a/tests/unit/resources/program/test_programs_media.py
+++ b/tests/unit/resources/program/test_programs_media.py
@@ -76,6 +76,12 @@ def test_media_primitive_fields(media_data):
     assert result.to_dict() == media_data
 
 
+def test_media_inherited_primitive_fields(media_inherited_data):
+    result = Media(media_inherited_data)
+
+    assert result.to_dict() == media_inherited_data
+
+
 def test_media_nested_fields_are_base_models(media_data):
     result = Media(media_data)
 
@@ -87,11 +93,14 @@ def test_media_optional_fields_absent():
     result = Media({"id": "PMD-001"})
 
     assert result.id == "PMD-001"
-    assert not hasattr(result, "name")
-    assert not hasattr(result, "type")
-    assert not hasattr(result, "description")
-    assert not hasattr(result, "status")
-    assert not hasattr(result, "filename")
-    assert not hasattr(result, "size")
-    assert not hasattr(result, "content_type")
-    assert not hasattr(result, "audit")
+    assert result.name is None
+    assert result.type is None
+    assert result.description is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.size is None
+    assert result.content_type is None
+    assert result.display_order is None
+    assert result.url is None
+    assert result.program is None
+    assert result.audit is None
diff --git a/tests/unit/resources/program/test_programs_terms_variant.py b/tests/unit/resources/program/test_programs_terms_variant.py
index 780334f0..ece2a8e2 100644
--- a/tests/unit/resources/program/test_programs_terms_variant.py
+++ b/tests/unit/resources/program/test_programs_terms_variant.py
@@ -87,6 +87,12 @@ def test_term_variant_primitive_fields(term_variant_data: dict) -> None:
     assert result.to_dict() == term_variant_data
 
 
+def test_term_variant_inherited_primitive_fields(term_variant_inherited_data: dict) -> None:
+    result = TermVariant(term_variant_inherited_data)
+
+    assert result.to_dict() == term_variant_inherited_data
+
+
 def test_term_variant_nested_base_model(term_variant_data: dict) -> None:
     result = TermVariant(term_variant_data)
 
@@ -98,13 +104,15 @@ def test_term_variant_optional_fields_absent() -> None:
     result = TermVariant({"id": "PTV-001"})
 
     assert result.id == "PTV-001"
-    assert not hasattr(result, "type")
-    assert not hasattr(result, "assetUrl")
-    assert not hasattr(result, "languageCode")
-    assert not hasattr(result, "name")
-    assert not hasattr(result, "description")
-    assert not hasattr(result, "status")
-    assert not hasattr(result, "filename")
-    assert not hasattr(result, "size")
-    assert not hasattr(result, "contentType")
-    assert not hasattr(result, "fileId")
+    assert result.name is None
+    assert result.type is None
+    assert result.asset_url is None
+    assert result.language_code is None
+    assert result.description is None
+    assert result.status is None
+    assert result.filename is None
+    assert result.size is None
+    assert result.content_type is None
+    assert result.file_id is None
+    assert result.program_terms_and_conditions is None
+    assert result.audit is None