Index: binaries/data/mods/public/gamesettings/attributes/PlayerAI.js
===================================================================
--- binaries/data/mods/public/gamesettings/attributes/PlayerAI.js
+++ binaries/data/mods/public/gamesettings/attributes/PlayerAI.js
@@ -48,7 +48,7 @@
 			}
 			this.set(+i, {
 				"bot": pData[i].AI,
-				"difficulty": pData[i].AIDiff || +Engine.ConfigDB_GetValue("user", "gui.gamesetup.aidifficulty"),
+				"difficulty": pData[i].AIDiff ?? +Engine.ConfigDB_GetValue("user", "gui.gamesetup.aidifficulty"),
 				"behavior": pData[i].AIBehavior || Engine.ConfigDB_GetValue("user", "gui.gamesetup.aibehavior"),
 			});
 		}
Index: binaries/system/readme.txt
===================================================================
--- binaries/system/readme.txt
+++ binaries/system/readme.txt
@@ -10,7 +10,7 @@
 -autostart="TYPEDIR/MAPNAME"    enables autostart and sets MAPNAME; TYPEDIR is skirmishes, scenarios, or random
 -autostart-seed=SEED            sets randomization seed value (default 0, use -1 for random)
 -autostart-ai=PLAYER:AI         sets the AI for PLAYER (e.g. 2:petra)
--autostart-aidiff=PLAYER:DIFF   sets the DIFFiculty of PLAYER's AI (0: sandbox, 5: very hard)
+-autostart-aidiff=PLAYER:DIFF   sets the DIFFiculty of PLAYER's AI (default 3, 0: sandbox, 5: very hard)
 -autostart-aiseed=AISEED        sets the seed used for the AI random generator (default 0, use -1 for random)
 -autostart-player=NUMBER        sets the playerID in non-networked games (default 1, use -1 for observer)
 -autostart-civ=PLAYER:CIV       sets PLAYER's civilisation to CIV (skirmish and random maps only). Use random for a random civ.