diff --git a/tests/unit/mcp/test_manager_byok.py b/tests/unit/mcp/test_manager_byok.py
index 6997ccb..7b24294 100644
--- a/tests/unit/mcp/test_manager_byok.py
+++ b/tests/unit/mcp/test_manager_byok.py
@@ -1,6 +1,7 @@
 """McpManager BYOK runtime — per-user clients, caching, fallback, LRU."""
 
 import asyncio
+import time
 from unittest.mock import MagicMock
 
 import pytest
@@ -233,9 +234,11 @@
     manager._evict_idle_user_clients()
     assert ("http-server", "u1") in manager._user_clients
 
-    # Backdate last-used past the idle threshold, then reap again.
+    # Backdate last-used past the idle threshold, then reap again. Backdating
+    # to 0.0 assumed a host that has been up longer than the threshold.
     client, key, _ = manager._user_clients[("http-server", "u1")]
-    manager._user_clients[("http-server", "u1")] = (client, key, 0.0)
+    stale = time.monotonic() - manager_mod._USER_CLIENT_IDLE_SEC - 1
+    manager._user_clients[("http-server", "u1")] = (client, key, stale)
     manager._evict_idle_user_clients()
     assert ("http-server", "u1") not in manager._user_clients