diff --git a/src/game/engine/scenes/headless/claude_player_main.gd b/src/game/engine/scenes/headless/claude_player_main.gd
index c013b34b..d7a9482c 100644
--- a/src/game/engine/scenes/headless/claude_player_main.gd
+++ b/src/game/engine/scenes/headless/claude_player_main.gd
@@ -192,7 +192,16 @@ func _apply_runtime_units_catalog(gs: RefCounted) -> void:
 	dir.list_dir_begin()
 	var fname: String = dir.get_next()
 	while fname != "":
-		if not dir.current_is_dir() and fname.ends_with(".json"):
+		# Skip `*.schema.json` — those are JSON Schema descriptors that
+		# live alongside the unit data files but describe the shape, not
+		# instances of it. Including them would feed the deserializer
+		# `{"$schema": "...", "type": "object", "properties": {...}}`
+		# without an `id` field, which correctly rejects.
+		if (
+			not dir.current_is_dir()
+			and fname.ends_with(".json")
+			and not fname.ends_with(".schema.json")
+		):
 			var path: String = UNITS_DIR + "/" + fname
 			var f: FileAccess = FileAccess.open(path, FileAccess.READ)
 			if f != null: