diff --git a/artiq/language/environment.py b/artiq/language/environment.py
index c61a1fa79..35654aab4 100644
--- a/artiq/language/environment.py
+++ b/artiq/language/environment.py
@@ -149,13 +149,14 @@ class HasEnvironment:
     """Provides methods to manage the environment of an experiment (devices,
     parameters, results, arguments)."""
     def __init__(self, device_mgr=None, dataset_mgr=None, *, parent=None,
-                 default_arg_none=False, **kwargs):
+                 default_arg_none=False, enable_processors=False, **kwargs):
         self.requested_args = OrderedDict()
 
         self.__device_mgr = device_mgr
         self.__dataset_mgr = dataset_mgr
         self.__parent = parent
         self.__default_arg_none = default_arg_none
+        self.__enable_processors = enable_processors
 
         self.__kwargs = kwargs
         self.__in_build = True
@@ -214,7 +215,10 @@ class HasEnvironment:
                     return None
                 else:
                     raise
-        return processor.process(argval)
+        if self.__enable_processors:
+            return processor.process(argval)
+        else:
+            return argval
 
     def setattr_argument(self, key, processor=None, group=None):
         """Sets an argument as attribute. The names of the argument and of the
diff --git a/artiq/master/worker_impl.py b/artiq/master/worker_impl.py
index e7f3ba8a1..2c06f1220 100644
--- a/artiq/master/worker_impl.py
+++ b/artiq/master/worker_impl.py
@@ -139,7 +139,8 @@ def examine(device_mgr, dataset_mgr, file):
                 if name[-1] == ".":
                     name = name[:-1]
             exp_inst = exp_class(device_mgr, dataset_mgr,
-                                 default_arg_none=True)
+                                 default_arg_none=True,
+                                 enable_processors=True)
             arginfo = OrderedDict(
                 (k, (proc.describe(), group))
                 for k, (proc, group) in exp_inst.requested_args.items())
@@ -209,7 +210,8 @@ def main():
                 device_mgr.virtual_devices["scheduler"].set_run_info(
                     rid, obj["pipeline_name"], expid, obj["priority"])
                 exp_inst = exp(
-                    device_mgr, dataset_mgr, **expid["arguments"])
+                    device_mgr, dataset_mgr, enable_processors=True,
+                    **expid["arguments"])
                 put_object({"action": "completed"})
             elif action == "prepare":
                 exp_inst.prepare()