diff --git a/src/bentoml/_internal/bento/bento.py b/src/bentoml/_internal/bento/bento.py
index 7046713bb49..f028f45d8e9 100644
--- a/src/bentoml/_internal/bento/bento.py
+++ b/src/bentoml/_internal/bento/bento.py
@@ -227,6 +227,7 @@ def get_manifest(self, dev: bool = False) -> BentoManifestSchema:
             version=info.version,
             dev=dev,
             image=image,
+            spec=info.spec,
         )
 
     @classmethod
@@ -743,6 +744,7 @@ class BaseBentoInfo:
     services: t.List[BentoServiceInfo] = attr.field(factory=list)
     envs: t.List[BentoEnvSchema] = attr.field(factory=list)
     schema: t.Dict[str, t.Any] = attr.field(factory=dict)
+    spec: int = attr.field(default=1)
 
     @property
     def all_models(self) -> t.List[BentoModelInfo]:
diff --git a/src/bentoml/_internal/cloud/schemas/modelschemas.py b/src/bentoml/_internal/cloud/schemas/modelschemas.py
index ec781a7e293..ede00bd12ff 100644
--- a/src/bentoml/_internal/cloud/schemas/modelschemas.py
+++ b/src/bentoml/_internal/cloud/schemas/modelschemas.py
@@ -89,6 +89,7 @@ class BentoManifestSchema:
     version: t.Optional[str] = attr.field(default=None, eq=False)
     dev: bool = attr.field(default=False, eq=False)
     image: t.Optional[ImageInfo] = None
+    spec: int = attr.field(default=1)
 
     @property
     def tag(self) -> Tag: