refactor

backend/app/tools/_dispatch.py

@@ -0,0 +1,13 @@
+from dataclasses import dataclass
+from typing import Any
+
+from sqlalchemy.orm import Session
+
+NOT_HANDLED: Any = object()
+
+
+@dataclass
+class ToolContext:
+    db: Session
+    user_id: int
+    session_id: int | None