fix(agent-runner): clean plugin review issues

src/langbot/pkg/provider/tools/loaders/skill_authoring.py

@@ -6,6 +6,7 @@ import typing
 import langbot_plugin.api.entities.builtin.resource.tool as resource_tool
 
 from .. import loader
+from .availability import is_box_backend_available
 
 # Align with Claude Code's Skill tool design:
 # - activate: Activate a skill via Tool Call, returns SKILL.md content
@@ -45,18 +46,7 @@ class SkillToolLoader(loader.ToolLoader):
 
     async def _check_sandbox_available(self) -> bool:
         """Check if the box backend is truly available (not just the runtime)."""
-        box_service = getattr(self.ap, 'box_service', None)
-        if box_service is None:
-            return False
-        if not getattr(box_service, 'available', False):
-            return False
-        # Check if backend is truly available via get_status
-        try:
-            status = await box_service.get_status()
-            backend_info = status.get('backend', {})
-            return backend_info.get('available', False)
-        except Exception:
-            return False
+        return await is_box_backend_available(self.ap)
 
     async def get_tools(self, bound_plugins: list[str] | None = None) -> list[resource_tool.LLMTool]:
         if not self._is_available():