diff --git a/src/seedpass/cli.py b/src/seedpass/cli.py
index 620678c..4b9a917 100644
--- a/src/seedpass/cli.py
+++ b/src/seedpass/cli.py
@@ -455,6 +455,14 @@ def vault_lock(ctx: typer.Context) -> None:
     typer.echo("locked")
 
 
+@app.command("lock")
+def root_lock(ctx: typer.Context) -> None:
+    """Lock the vault for the active profile."""
+    vault_service, _profile, _sync = _get_services(ctx)
+    vault_service.lock()
+    typer.echo("locked")
+
+
 @vault_app.command("stats")
 def vault_stats(ctx: typer.Context) -> None:
     """Display statistics about the current seed profile."""
diff --git a/src/seedpass/core/manager.py b/src/seedpass/core/manager.py
index 74a0da1..a707391 100644
--- a/src/seedpass/core/manager.py
+++ b/src/seedpass/core/manager.py
@@ -109,6 +109,24 @@ class Notification:
     level: str = "INFO"
 
 
+class AuthGuard:
+    """Helper to enforce inactivity timeouts."""
+
+    def __init__(
+        self, manager: "PasswordManager", time_fn: callable = time.time
+    ) -> None:
+        self.manager = manager
+        self._time_fn = time_fn
+
+    def check_timeout(self) -> None:
+        """Lock the vault if the inactivity timeout has been exceeded."""
+        timeout = getattr(self.manager, "inactivity_timeout", 0)
+        if self.manager.locked or timeout <= 0:
+            return
+        if self._time_fn() - self.manager.last_activity > timeout:
+            self.manager.lock_vault()
+
+
 class PasswordManager:
     """
     PasswordManager Class
@@ -161,6 +179,7 @@ class PasswordManager:
         self._suppress_entry_actions_menu: bool = False
         self.last_bip85_idx: int = 0
         self.last_sync_ts: int = 0
+        self.auth_guard = AuthGuard(self)
 
         # Initialize the fingerprint manager first
         self.initialize_fingerprint_manager()
@@ -240,7 +259,12 @@ class PasswordManager:
         return (None, parent_fp, self.current_fingerprint)
 
     def update_activity(self) -> None:
-        """Record the current time as the last user activity."""
+        """Record activity and enforce inactivity timeout."""
+        guard = getattr(self, "auth_guard", None)
+        if guard is None:
+            guard = AuthGuard(self)
+            self.auth_guard = guard
+        guard.check_timeout()
         self.last_activity = time.time()
 
     def notify(self, message: str, level: str = "INFO") -> None:
diff --git a/src/tests/test_inactivity_lock.py b/src/tests/test_inactivity_lock.py
index 32d81da..2befaed 100644
--- a/src/tests/test_inactivity_lock.py
+++ b/src/tests/test_inactivity_lock.py
@@ -91,3 +91,32 @@ def test_input_timeout_triggers_lock(monkeypatch):
 
     assert locked["locked"] == 1
     assert locked["unlocked"] == 1
+
+
+def test_update_activity_checks_timeout(monkeypatch):
+    """AuthGuard in update_activity locks the vault after inactivity."""
+    import seedpass.core.manager as manager
+
+    now = {"val": 0.0}
+    monkeypatch.setattr(manager.time, "time", lambda: now["val"])
+
+    pm = manager.PasswordManager.__new__(manager.PasswordManager)
+    pm.inactivity_timeout = 0.5
+    pm.last_activity = 0.0
+    pm.locked = False
+    called = {}
+
+    def lock():
+        called["locked"] = True
+        pm.locked = True
+
+    pm.lock_vault = lock
+    pm.auth_guard = manager.AuthGuard(pm, time_fn=lambda: now["val"])
+
+    now["val"] = 0.4
+    pm.update_activity()
+    assert not called
+
+    now["val"] = 1.1
+    pm.update_activity()
+    assert called["locked"] is True
diff --git a/src/tests/test_typer_cli.py b/src/tests/test_typer_cli.py
index eb71f62..3d51993 100644
--- a/src/tests/test_typer_cli.py
+++ b/src/tests/test_typer_cli.py
@@ -153,6 +153,23 @@ def test_vault_lock(monkeypatch):
     assert pm.locked is True
 
 
+def test_root_lock(monkeypatch):
+    called = {}
+
+    def lock():
+        called["locked"] = True
+        pm.locked = True
+
+    pm = SimpleNamespace(
+        lock_vault=lock, locked=False, select_fingerprint=lambda fp: None
+    )
+    monkeypatch.setattr(cli, "PasswordManager", lambda: pm)
+    result = runner.invoke(app, ["lock"])
+    assert result.exit_code == 0
+    assert called.get("locked") is True
+    assert pm.locked is True
+
+
 def test_vault_reveal_parent_seed(monkeypatch, tmp_path):
     called = {}