diff --git a/src/game/engine/scenes/tests/auto_play.gd b/src/game/engine/scenes/tests/auto_play.gd
index a267d4ee..b8aaabc2 100644
--- a/src/game/engine/scenes/tests/auto_play.gd
+++ b/src/game/engine/scenes/tests/auto_play.gd
@@ -1424,6 +1424,64 @@ func _next_building(city: Variant, player: Variant, city_count: int, has_founder
 				best_wonder = bid
 		if not best_wonder.is_empty():
 			return best_wonder
+	# p0-39: upgrade `warrior` to the highest-tier buildable melee unit for
+	# this player. Makes tier progression emergent — pikeman replaces warrior
+	# once bronze_working unlocks; cavalry replaces pikeman once steelworking
+	# AND iron_ore both land; berserker/ironwarden/forge_titan/mithril_vanguard
+	# for dwarf clans as their tech chain progresses.
+	if best_id == "warrior":
+		var upgrade: String = _best_melee_for_player(player, city)
+		if not upgrade.is_empty() and upgrade != "warrior":
+			best_id = upgrade
+	return best_id
+
+
+func _best_melee_for_player(player: RefCounted, city: Variant) -> String:
+	# Highest-tier buildable melee unit per p0-39 rules:
+	# - unit_type == "military" AND not in the ranged-specialist set
+	# - tech_required satisfied (player.has_tech) if set
+	# - requires_resource satisfied (BuildableHelper) if set
+	# - race_required matches player.race_id if set
+	# Returns "warrior" when no higher-tier candidate qualifies.
+	var best_id: String = "warrior"
+	var best_tier: int = 1
+	var ranged_keywords: Array[String] = [
+		"archer", "ranger", "arbalest", "crossbow", "flying", "catapult", "ballista",
+	]
+	for u: Dictionary in DataLoader.get_all_units():
+		var uid: String = str(u.get("id", ""))
+		if uid.is_empty():
+			continue
+		var unit_type: String = str(u.get("unit_type", ""))
+		if unit_type != "military":
+			continue
+		var is_ranged: bool = false
+		for kw: String in ranged_keywords:
+			if uid.contains(kw):
+				is_ranged = true
+				break
+		if is_ranged:
+			continue
+		var tier: int = int(u.get("tier", 1))
+		if tier <= best_tier:
+			continue
+		var tech_req: String = str(u.get("tech_required", ""))
+		if not tech_req.is_empty() and tech_req != "<null>" and not player.has_tech(tech_req):
+			continue
+		var race_req: String = str(u.get("race_required", ""))
+		if not race_req.is_empty() and race_req != "<null>":
+			var player_race: String = str(player.race_id) if "race_id" in player else ""
+			if race_req != player_race:
+				continue
+		var res_req: String = str(u.get("requires_resource", ""))
+		if not res_req.is_empty() and res_req != "<null>":
+			if not BuildableHelperScript.player_owns_resource(player, res_req):
+				continue
+		# Also require the engine agrees this city can build it.
+		if not city.can_build(uid, player):
+			continue
+		best_tier = tier
+		best_id = uid
 	return best_id