diff --git a/game_api.txt b/game_api.txt
index 4e2bae29..d715312b 100644
--- a/game_api.txt
+++ b/game_api.txt
@@ -1124,6 +1124,8 @@ Logs action of the player with a node at a certain position.
 By default only actions of real players are logged.
 Actions of non-players (usually machines) are logged only when
 setting `enable_non_player_action_log` is enabled.
+A player is considered non-player if `player.is_player()` returns
+`false` or `player.is_fake_player` is truthy.
 
 `default.log_action(player, pos, message)`