diff --git a/src/game/engine/scenes/headless/claude_player_main.gd b/src/game/engine/scenes/headless/claude_player_main.gd
index 1298e44a..0c40d039 100644
--- a/src/game/engine/scenes/headless/claude_player_main.gd
+++ b/src/game/engine/scenes/headless/claude_player_main.gd
@@ -190,15 +190,23 @@ func _apply_runtime_units_catalog(gs: RefCounted) -> void:
 				# Per-unit file is either a single object or a single-element
 				# array (canonical post-data-architecture migration is array-
 				# rooted; pre-migration is object-rooted). Accept both shapes.
-				# Rust loader accepts an array; we always ship one.
-				var parsed_arr: Array = JSON.parse_string(raw) as Array
-				if parsed_arr != null:
+				# Rust loader takes an array; we always ship one.
+				#
+				# Discriminate by first non-whitespace character of the raw
+				# JSON: `[` → array shape, `{` → object shape. Avoids the
+				# strict-typed-cast trap where `as Array` on a Dictionary
+				# value throws an "Invalid cast" runtime error instead of
+				# returning null.
+				var stripped: String = raw.strip_edges()
+				var head: String = stripped.substr(0, 1)
+				if head == "[":
+					var parsed_arr: Array = JSON.parse_string(stripped) as Array
 					for item: Dictionary in parsed_arr:
 						if not item.is_empty():
 							entries.append(item)
-				else:
-					var parsed_obj: Dictionary = JSON.parse_string(raw) as Dictionary
-					if parsed_obj != null and not parsed_obj.is_empty():
+				elif head == "{":
+					var parsed_obj: Dictionary = JSON.parse_string(stripped) as Dictionary
+					if not parsed_obj.is_empty():
 						entries.append(parsed_obj)
 		fname = dir.get_next()
 	dir.list_dir_end()