diff --git a/api/controllers/console/app/workflow.py b/api/controllers/console/app/workflow.py
index 88dcc8bb83..47359f902e 100644
--- a/api/controllers/console/app/workflow.py
+++ b/api/controllers/console/app/workflow.py
@@ -1425,9 +1425,14 @@ class WorkflowOnlineUsersApi(Resource):
                 if isinstance(avatar, str) and avatar and not avatar.startswith(("http://", "https://")):
                     try:
                         user_info["avatar"] = file_helpers.get_signed_file_url(avatar)
-                    except Exception:
-                        # keep original avatar value when signing fails
-                        pass
+                    except Exception as exc:
+                        logger.warning(
+                            "Failed to sign workflow online user avatar; using original value. "
+                            "app_id=%s avatar=%s error=%s",
+                            app_id,
+                            avatar,
+                            exc,
+                        )
 
                 users.append(user_info)
             results.append({"app_id": app_id, "users": users})
diff --git a/api/controllers/console/app/workflow_comment.py b/api/controllers/console/app/workflow_comment.py
index c10b697d90..e7c3e982a6 100644
--- a/api/controllers/console/app/workflow_comment.py
+++ b/api/controllers/console/app/workflow_comment.py
@@ -26,17 +26,15 @@ logger = logging.getLogger(__name__)
 DEFAULT_REF_TEMPLATE_SWAGGER_2_0 = "#/definitions/{model}"
 
 
-class WorkflowCommentContentPayload(BaseModel):
+class WorkflowCommentCreatePayload(BaseModel):
     content: str = Field(..., description="Comment content")
+    position_x: float = Field(..., description="Comment X position")
+    position_y: float = Field(..., description="Comment Y position")
     mentioned_user_ids: list[str] = Field(default_factory=list, description="Mentioned user IDs")
 
 
-class WorkflowCommentCreatePayload(WorkflowCommentContentPayload):
-    position_x: float = Field(..., description="Comment X position")
-    position_y: float = Field(..., description="Comment Y position")
-
-
-class WorkflowCommentUpdatePayload(WorkflowCommentContentPayload):
+class WorkflowCommentUpdatePayload(BaseModel):
+    content: str = Field(..., description="Comment content")
     position_x: float | None = Field(default=None, description="Comment X position")
     position_y: float | None = Field(default=None, description="Comment Y position")
     mentioned_user_ids: list[str] | None = Field(
@@ -45,8 +43,9 @@ class WorkflowCommentUpdatePayload(WorkflowCommentContentPayload):
     )
 
 
-class WorkflowCommentReplyPayload(WorkflowCommentContentPayload):
+class WorkflowCommentReplyPayload(BaseModel):
     content: str = Field(..., description="Reply content")
+    mentioned_user_ids: list[str] = Field(default_factory=list, description="Mentioned user IDs")
 
 
 class WorkflowCommentMentionUsersPayload(BaseModel):