diff --git a/tests/gateway/test_async_session_db.py b/tests/gateway/test_async_session_db.py
index c09b5485ae7c..8799bb0a8937 100644
--- a/tests/gateway/test_async_session_db.py
+++ b/tests/gateway/test_async_session_db.py
@@ -125,8 +125,10 @@ _GATEWAY_FILES = ("gateway/run.py", "gateway/slash_commands.py")
 #   - self._session_db._db.<x>: the sync escape, allowed ONLY where the call is
 #     provably off the event loop — construction (__init__, before the loop
 #     serves) and the run_sync closure (executed in a thread-pool executor).
-#     Three such sites today; a fourth must be justified and this count bumped.
-_ALLOWED_SYNC_DB_ESCAPES = 3
+#     Four such sites today (maybe_auto_archive joined maybe_auto_prune_and_vacuum
+#     in the construction-time maintenance block); a fifth must be justified and
+#     this count bumped.
+_ALLOWED_SYNC_DB_ESCAPES = 4
 
 # Sync helpers that touch SessionDB but are NEVER invoked bare on the loop:
 # every loop-side call wraps them in ``asyncio.to_thread(...)`` and the only