diff --git a/backend/druks/browser/constants.py b/backend/druks/browser/constants.py
index a14ba762..f5c6b8ae 100644
--- a/backend/druks/browser/constants.py
+++ b/backend/druks/browser/constants.py
@@ -5,13 +5,14 @@
 BROWSER_SESSION_NAME_PATTERN = r"^[a-z](?:[a-z0-9-]*[a-z0-9])?$"
 SITE_MAX_LENGTH = 255
 
-WRITER_LOCK_TTL_SECONDS = 60
+# TTL-only, no renewal: must outlast the longest borrow, bounded by the
+# browser container's 150-minute lease.
+WRITER_LOCK_TTL_SECONDS = 3 * 60 * 60
 SESSION_LAUNCH_TIMEOUT_SECONDS = 45
 SESSION_EXPORT_TIMEOUT_SECONDS = 5 * 60
 
-# A login window holds the session's writer lock and its Redis record for as
-# long as it may stay open; both lapse together if the operator walks away, and
-# the container's own lease reaps it — nothing sweeps.
+# A login window keeps only this Redis record; if the operator walks away it
+# lapses and the container's own lease reaps the browser — nothing sweeps.
 LOGIN_WINDOW_TTL_SECONDS = 30 * 60
 LOGIN_WINDOW_KEY_PREFIX = "browser_login_window:"