diff --git a/Jellyfin.Plugin.SmartPlaylist/Lisp/Interpreter.cs b/Jellyfin.Plugin.SmartPlaylist/Lisp/Interpreter.cs
index df40feb..265ecd5 100644
--- a/Jellyfin.Plugin.SmartPlaylist/Lisp/Interpreter.cs
+++ b/Jellyfin.Plugin.SmartPlaylist/Lisp/Interpreter.cs
@@ -113,7 +113,7 @@ namespace Jellyfin.Plugin.SmartPlaylist.Lisp {
 
     public class Builtins : Dictionary<string, Function> {
 
-        private static Dictionary<string, Assembly> AssemblyMapping = new Dictionary<string, Assembly>();
+        private static Dictionary<string, Type?> ResolvedTypes = new Dictionary<string, Type?>();
 
         public Builtins() : base() {
             this["atom"] = _atom;
@@ -261,12 +261,17 @@ namespace Jellyfin.Plugin.SmartPlaylist.Lisp {
         }
 
         private static Type? GetType(string name) {
-            return Type.GetType(
+            if (ResolvedTypes.ContainsKey(name)) {
+                return ResolvedTypes[name];
+            }
+            var t = Type.GetType(
                 name,
                 (name) => { return AppDomain.CurrentDomain.GetAssemblies().Where(z => (z.FullName != null) && z.FullName.StartsWith(name.FullName)).FirstOrDefault(); },
                 null,
                 true
             );
+            ResolvedTypes[name] = t;
+            return t;
         }
 
         private static Expression _invoke_generic(IEnumerable<Expression> args) {