diff --git a/internal/engine.cm b/internal/engine.cm
index d49c9589..af3ad891 100644
--- a/internal/engine.cm
+++ b/internal/engine.cm
@@ -49,9 +49,13 @@ function ends_with(str, suffix) {
   return search(str, suffix, -length(suffix)) != null
 }
 
+print("engine: loading js")
 var js = use_embed('js')
+print("engine: loading fd")
 var fd = use_embed('fd')
+print("engine: loaded fd")
 
+print("engine: getting home")
 // Get the shop path from HOME environment
 var home = os.getenv('HOME') || os.getenv('USERPROFILE')
 if (!home) {
@@ -76,34 +80,49 @@ function use_core(path) {
   if (use_cache[cache_key])
     return use_cache[cache_key];
 
+  print(`engine: use_core('${path}') - embed`)
   var sym = use_embed(replace(path, '/', '_'))
 
   // Core scripts are in packages/core/
   var file_path = core_path + '/' + path + MOD_EXT
 
   if (fd.is_file(file_path)) {
+    print(`engine: use_core('${path}') - loading script`)
     var script_blob = fd.slurp(file_path)
     var script = text(script_blob)
     var mod = `(function setup_module(use){${script}})`
     var fn = mach_eval('core:' + path, mod)
+    if (fn == null) {
+      print(`engine: use_core('${path}') - mach_eval returned null!`)
+      return null
+    }
+    print(`engine: use_core('${path}') - calling (fn type: ${typeof(fn)})`)
     var result = call(fn,sym, [use_core])
+    print(`engine: use_core('${path}') - done`)
     use_cache[cache_key] = result;
     return result;
   }
 
+  print(`engine: use_core('${path}') - using embed directly`)
   use_cache[cache_key] = sym;
   return sym;
 }
 
+print("engine: loading blob")
 var blob = use_core('blob')
+print("engine: loaded blob")
 
 function actor() {
 
 }
 
+print("engine: loading actor")
 var actor_mod = use_core('actor')
+print("engine: loading wota")
 var wota = use_core('wota')
+print("engine: loading nota")
 var nota = use_core('nota')
+print("engine: loaded nota")
 
 function is_actor(value) {
   return is_object(value) && value[ACTORDATA]
@@ -191,10 +210,15 @@ function actor_die(err)
 
 
 
+print("engine: setting up actor_die")
 actor_mod.on_exception(actor_die)
 
+print("engine: setting cell args")
+print(`engine: init is ${init}`)
 _cell.args = init != null ? init : {}
+print("engine: args set")
 _cell.id = "newguy"
+print("engine: id set")
 
 function create_actor(desc = {id:guid()}) {
   var actor = {}
@@ -202,19 +226,25 @@ function create_actor(desc = {id:guid()}) {
   return actor
 }
 
+print("engine: creating $_")
 var $_ = {}
+print("engine: creating self actor")
 $_.self = create_actor()
-
+print("engine: setting os props")
 os.use_cache = use_cache
 os.global_shop_path = shop_path
 os.$_ = $_
+print("engine: os props set")
 
+print("engine: loading shop")
 var shop = use_core('internal/shop')
-
+print("engine: loaded shop, loading json")
 var json = use_core('json')
 var time = use_core('time')
 
+print("engine: loading pronto")
 var pronto = use_core('pronto')
+print("engine: loaded pronto")
 var fallback = pronto.fallback
 var parallel = pronto.parallel
 var race = pronto.race
diff --git a/internal/shop.cm b/internal/shop.cm
index 676e63d5..15bc07f7 100644
--- a/internal/shop.cm
+++ b/internal/shop.cm
@@ -1,5 +1,6 @@
+print("shop: starting")
 var toml = use('toml')
-
+print("shop: loaded toml")
 var json = use('json')
 var fd = use('fd')
 var http = use('http')
diff --git a/source/cell.c b/source/cell.c
index 9eef6894..2828237a 100644
--- a/source/cell.c
+++ b/source/cell.c
@@ -215,22 +215,19 @@ void script_startup(cell_rt *prt)
   JS_PushGCRef(js, &env_ref);
   env_ref.val = JS_NewObject(js);
 
+  // Create modules with GC rooting
   JSGCRef os_ref, json_ref, nota_ref, wota_ref;
   JS_PushGCRef(js, &os_ref);
   JS_PushGCRef(js, &json_ref);
   JS_PushGCRef(js, &nota_ref);
   JS_PushGCRef(js, &wota_ref);
 
-  // Create and stone each module to make them GC-immovable
   os_ref.val = js_os_use(js);
-  os_ref.val = JS_Stone(js, os_ref.val);
   json_ref.val = js_json_use(js);
-  json_ref.val = JS_Stone(js, json_ref.val);
   nota_ref.val = js_nota_use(js);
-  nota_ref.val = JS_Stone(js, nota_ref.val);
   wota_ref.val = js_wota_use(js);
-  wota_ref.val = JS_Stone(js, wota_ref.val);
 
+  // Set properties on env (SetPropertyStr internally roots its args)
   JS_SetPropertyStr(js, env_ref.val, "os", os_ref.val);
   JS_SetPropertyStr(js, env_ref.val, "json", json_ref.val);
   JS_SetPropertyStr(js, env_ref.val, "nota", nota_ref.val);