diff --git a/chatkit/types.py b/chatkit/types.py
index 12c062a..c84c3db 100644
--- a/chatkit/types.py
+++ b/chatkit/types.py
@@ -856,7 +856,14 @@ class EntitySource(SourceBase):
     type: Literal["entity"] = "entity"
     id: str
     icon: IconName | None = None
+    label: str | None = None
+    """Optional label shown with the icon in the default entity hover header
+    when no preview callback is provided.
+    """
+    interactive: bool = False
+    """Per-entity toggle to wire client callbacks and render this entity as interactive."""
     data: dict[str, Any] = Field(default_factory=dict)
+    """Additional data for the entity source that is passed to client entity callbacks."""
 
     preview: Literal["lazy"] | None = Field(
         default=None,