diff --git a/src/app_controller.py b/src/app_controller.py
index 0d2d4663..5433dceb 100644
--- a/src/app_controller.py
+++ b/src/app_controller.py
@@ -2002,8 +2002,7 @@ class AppController:
     self.ai_status = f"Manual prune error: {e}"
     print(f"Error during manual log pruning: {e}")
 
-  thread = threading.Thread(target=run_manual_prune, daemon=True)
-  thread.start()
+  self.submit_io(run_manual_prune)
 
  def _load_active_project(self) -> None:
   """Loads the active project configuration, with fallbacks."""
@@ -2052,8 +2051,7 @@ class AppController:
     pruner.prune()
    except Exception as e:
     print(f"Error during log pruning: {e}")
-  thread = threading.Thread(target=run_prune, daemon=True)
-  thread.start()
+  self.submit_io(run_prune)
 
  def _fetch_models(self, provider: str) -> None:
   """
@@ -2152,6 +2150,25 @@ class AppController:
   """
   self._warmup.on_complete(callback)
 
+ def submit_io(self, fn: Callable, *args: Any, **kwargs: Any) -> Any:
+  """
+  Submit a background job to the shared _io_pool. Use this for any
+  fire-and-forget background work; avoids the per-spawn cost of a new
+  threading.Thread.
+
+  Returns a concurrent.futures.Future that can be used to track
+  completion, raise exceptions, or cancel the job. The pool is capped
+  at 4 workers (see src/io_pool.py) so the job may queue briefly if
+  the pool is saturated.
+
+  Domain-specific threads (HookServer, WebSocketServer, MMA WorkerPool,
+  asyncio loop) are NOT submitted here - they have their own lifecycle
+  management.
+  [SDM: src/app_controller.py:submit_io]
+  """
+  import concurrent.futures
+  return self._io_pool.submit(fn, *args, **kwargs)
+
  def shutdown(self) -> None:
   """