diff --git a/xo-interpreter2/include/xo/interpreter2/VirtualSchematikaMachine.hpp b/xo-interpreter2/include/xo/interpreter2/VirtualSchematikaMachine.hpp
index 6663538e..290eaf09 100644
--- a/xo-interpreter2/include/xo/interpreter2/VirtualSchematikaMachine.hpp
+++ b/xo-interpreter2/include/xo/interpreter2/VirtualSchematikaMachine.hpp
@@ -100,9 +100,6 @@ namespace xo {
             /** visit vsm-owned memory pools; call visitor(info) for each **/
             void visit_pools(const MemorySizeVisitor & visitor) const;
 
-            /** install hardwired functions into global {symtab,env} **/
-            void install_core_primitives();
-
             /** begin interactive session. **/
             void begin_interactive_session();
             /** begin batch session **/
diff --git a/xo-interpreter2/src/interpreter2/VirtualSchematikaMachine.cpp b/xo-interpreter2/src/interpreter2/VirtualSchematikaMachine.cpp
index 74612aa6..d459622a 100644
--- a/xo-interpreter2/src/interpreter2/VirtualSchematikaMachine.cpp
+++ b/xo-interpreter2/src/interpreter2/VirtualSchematikaMachine.cpp
@@ -86,8 +86,6 @@ namespace xo {
             }
 
             this->global_env_ = reader_.global_env();
-
-            this->install_core_primitives();
         }
 
         obj<AAllocator>
@@ -875,45 +873,6 @@ namespace xo {
             }
          }
 
-        // ----- primitive: fn_n_args() -----
-
-        obj<AGCObject>
-        xfer_fn_n_args(obj<ARuntimeContext> rcx,
-                       obj<AGCObject> fn_gco)
-        {
-            scope log(XO_DEBUG(true));
-
-            log && log(xtag("fn_gco.tseq", fn_gco._typeseq()));
-            log && log(xtag("fn_gco.tname", TypeRegistry::id2name(fn_gco._typeseq())));
-
-            auto fn_proc = FacetRegistry::instance().try_variant<AProcedure,AGCObject>(fn_gco);
-
-            assert(fn_proc);
-
-            return DInteger::box<AGCObject>(rcx.allocator(), fn_proc.n_args());
-        }
-
-        static DPrimitive_gco_1_gco s_fn_n_args_pm("_fn_n_args",
-                                                   &xfer_fn_n_args);
-
-        // ----- install primitives -----
-
-        void
-        VirtualSchematikaMachine::install_core_primitives()
-        {
-            /* fn_n_args */
-            {
-                const DUniqueString * name
-                    = reader_.intern_string("fn_n_args");
-
-                global_env_->_upsert_value
-                    (mm_.to_op(),
-                     name,
-                     Reflect::require<DPrimitive_gco_1_gco>(),
-                     obj<AGCObject,DPrimitive_gco_1_gco>(&s_fn_n_args_pm));
-            }
-        }
-
     } /*namespace scm*/
 } /*namespace xo*/
 
diff --git a/xo-procedure2/include/xo/procedure2/ObjectPrimitives.hpp b/xo-procedure2/include/xo/procedure2/ObjectPrimitives.hpp
index ee2dfae0..1de2fd2d 100644
--- a/xo-procedure2/include/xo/procedure2/ObjectPrimitives.hpp
+++ b/xo-procedure2/include/xo/procedure2/ObjectPrimitives.hpp
@@ -6,6 +6,7 @@
 #pragma once
 
 #include "Primitive_gco_0.hpp"
+#include "Primitive_gco_1_gco.hpp"
 #include "Primitive_gco_2_gco_gco.hpp"
 #include "Primitive_gco_3_dict_string_gco.hpp"
 
@@ -35,6 +36,9 @@ namespace xo {
 
             /** create primitive that upserts a key,value pair into a dictionary **/
             static DPrimitive_gco_3_dict_string_gco * make_dict_upsert_pm(obj<AAllocator> mm);
+
+            /** create primitive: get fixed number of args for function **/
+            static DPrimitive_gco_1_gco * make_fn_n_args_pm(obj<AAllocator> mm);
         };
 
     } /*namespace scm*/
diff --git a/xo-procedure2/src/procedure2/ObjectPrimitives.cpp b/xo-procedure2/src/procedure2/ObjectPrimitives.cpp
index f5d7ab15..29e9e9bb 100644
--- a/xo-procedure2/src/procedure2/ObjectPrimitives.cpp
+++ b/xo-procedure2/src/procedure2/ObjectPrimitives.cpp
@@ -133,6 +133,30 @@ namespace xo {
             return DPrimitive_gco_3_dict_string_gco::_make(mm, "dict_upsert", &xfer_dict_upsert);
         }
 
+        // ----- fn_n_args -----
+
+        obj<AGCObject>
+        xfer_fn_n_args(obj<ARuntimeContext> rcx,
+                       obj<AGCObject> fn_gco)
+        {
+            scope log(XO_DEBUG(true));
+
+            log && log(xtag("fn_gco.tseq", fn_gco._typeseq()));
+            log && log(xtag("fn_gco.tname", TypeRegistry::id2name(fn_gco._typeseq())));
+
+            auto fn_proc = FacetRegistry::instance().try_variant<AProcedure,AGCObject>(fn_gco);
+
+            assert(fn_proc);
+
+            return DInteger::box<AGCObject>(rcx.allocator(), fn_proc.n_args());
+        }
+
+        DPrimitive_gco_1_gco *
+        ObjectPrimitives::make_fn_n_args_pm(obj<AAllocator> mm)
+        {
+            return DPrimitive_gco_1_gco::_make(mm, "fn_n_args", &xfer_fn_n_args);
+        }
+
     } /*namespace scm*/
 } /*namespace xo*/
 
diff --git a/xo-procedure2/src/procedure2/procedure2_register_primitives.cpp b/xo-procedure2/src/procedure2/procedure2_register_primitives.cpp
index a5502d68..2585457b 100644
--- a/xo-procedure2/src/procedure2/procedure2_register_primitives.cpp
+++ b/xo-procedure2/src/procedure2/procedure2_register_primitives.cpp
@@ -66,6 +66,7 @@ namespace xo {
             ok = ok & install_aux(sink, ObjectPrimitives::make_cons_pm(mm), flags);
             ok = ok & install_aux(sink, ObjectPrimitives::make_dict_make_pm(mm), flags);
             ok = ok & install_aux(sink, ObjectPrimitives::make_dict_upsert_pm(mm), flags);
+            ok = ok & install_aux(sink, ObjectPrimitives::make_fn_n_args_pm(mm), flags);
 
             return ok;
         }