diff --git a/hermes_cli/config_defaults.py b/hermes_cli/config_defaults.py
index d6763c583d..e7d02a75d9 100644
--- a/hermes_cli/config_defaults.py
+++ b/hermes_cli/config_defaults.py
@@ -2086,15 +2086,15 @@ DEFAULT_CONFIG = {
     # Automatic cleanup of ~/.hermes/state.db, which otherwise grows without bound and slows FTS5
     # inserts, /resume listing, and insights queries.
     "sessions": {
-        # Prune ENDED sessions inactive for retention_days (activity = latest message, else
-        # creation) about once per min_interval_hours at startup. Open, pinned, or mid-turn sessions
+        # Prune ENDED sessions inactive for retention_days (activity = freshest of live activity /
+        # latest message / creation) about once per min_interval_hours at startup. Open, pinned, or mid-turn sessions
         # are never deleted; stale automation sessions whose process died are *closed*, then get a
         # full retention window before removal.
         "auto_prune": True,
         # Inactive days of ended-session history to keep (= `hermes sessions prune`).
         # When true, prune ENDED sessions inactive for retention_days once per (roughly) min_interval_hours
-        # at CLI/gateway/cron startup. Activity is the latest message timestamp, falling back to creation
-        # time for empty sessions. Sessions that are still open, pinned, or mid-turn are never deleted — the
+        # at CLI/gateway/cron startup. Activity is the freshest of live activity (last_activity_at) / latest
+        # message timestamp / creation time. Sessions that are still open, pinned, or mid-turn are never deleted — the
         # only open rows the sweep touches are stale automation sessions (cron/kanban/subagent/one-shot CLI)
         # whose process died without closing them; those are *closed*, not deleted, and get a further full
         # retention window before removal. Default true since #54189: without it state.db grows without
diff --git a/hermes_cli/session_filters.py b/hermes_cli/session_filters.py
index ea8693dd6d..ef1649534f 100644
--- a/hermes_cli/session_filters.py
+++ b/hermes_cli/session_filters.py
@@ -96,8 +96,8 @@ _ARG_FILTERS = (
 def build_prune_filters(args: Any) -> Dict[str, Any]:
     """Translate argparse Namespace flags into SessionDB filter kwargs.
 
-    ``--older-than`` / ``--newer-than`` bound last activity (latest message timestamp, falling back
-    to ``started_at`` for empty sessions); ``--before`` / ``--after`` bound session start time.
+    ``--older-than`` / ``--newer-than`` bound last activity (freshest of ``last_activity_at`` /
+    latest message / ``started_at``); ``--before`` / ``--after`` bound session start time.
     """
     bounds: Dict[str, Optional[float]] = {
         key: None if (raw := getattr(args, attr, None)) is None else parse_point_in_time(raw, flag)
diff --git a/hermes_state_maintenance.py b/hermes_state_maintenance.py
index a870470cb0..71f038be1a 100644
--- a/hermes_state_maintenance.py
+++ b/hermes_state_maintenance.py
@@ -209,7 +209,7 @@ class SessionMaintenanceMixin:
     def list_prune_candidates(self, older_than_days: Optional[float] = None, source: str = None,
                               **filters) -> List[Dict[str, Any]]:
         """Dry-run: sessions a matching prune/archive would touch, oldest first (``older_than_days``
-        = inactivity threshold: latest message, else ``started_at``)."""
+        = inactivity threshold: freshest of ``last_activity_at`` / latest message / ``started_at``)."""
         where, params = self._prune_where(older_than_days, source, filters)
         return [dict(row) for row in self._read_all(
             f"""SELECT s.id, s.source, s.title, s.model, s.started_at,
@@ -253,7 +253,7 @@ class SessionMaintenanceMixin:
               AND COALESCE(s.end_reason, '') <> 'compression'
               {pin_clause}
               AND NOT (COALESCE(s.hidden, 0) <> 0 AND COALESCE(s.title, '') = ?)
-              AND {_sql_session_last_active("s")} < ?
+              AND {_LAST_ACTIVE_SQL} < ?
             ORDER BY s.started_at ASC
             """, (self.CANONICAL_BOT_CHAT_TITLE, cutoff))
         for row in rows: