diff --git a/CMakeLists.txt b/CMakeLists.txt
index a0e0b1df..592bf697 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -102,9 +102,9 @@ add_subdirectory(xo-alloc2)   # experiment w/ facet object model
 add_subdirectory(xo-gc)
 add_subdirectory(xo-object)
 add_subdirectory(xo-object2)  # experiment w/ facet object model
+add_subdirectory(xo-procedure2)  # schematika procedure abstraction + runtime context (fomo)
 add_subdirectory(xo-ordinaltree)
 #
-add_subdirectory(xo-procedure2)  # schematika procedure abstraction + runtime context (fomo)
 add_subdirectory(xo-tokenizer2)  # schematika tokenizer (fomo)
 add_subdirectory(xo-expression2)  # schematika expressions (fomo)
 add_subdirectory(xo-reader2)       # schematika expression parser (fomo)
diff --git a/xo-procedure2/CMakeLists.txt b/xo-procedure2/CMakeLists.txt
index acb0bad9..be7909a5 100644
--- a/xo-procedure2/CMakeLists.txt
+++ b/xo-procedure2/CMakeLists.txt
@@ -53,6 +53,18 @@ xo_add_genfacetimpl(
     OUTPUT_CPP_DIR src/procedure2
 )
 
+# note: manual target; generated code committed to git
+xo_add_genfacetimpl(
+    TARGET xo-procedure2-facetimpl-gcobject-primitive_gco_2_gco_gco
+    FACET_PKG xo_gc
+    FACET GCObject
+    REPR Primitive_gco_2_gco_gco
+    INPUT idl/IGCObject_DPrimitive_gco_2_gco_gco.json5
+    OUTPUT_HPP_DIR include/xo/procedure2
+    OUTPUT_IMPL_SUBDIR detail
+    OUTPUT_CPP_DIR src/procedure2
+)
+
 add_subdirectory(src/procedure2)
 #add_subdirectory(utest)
 
diff --git a/xo-procedure2/cmake/xo_procedure2Config.cmake.in b/xo-procedure2/cmake/xo_procedure2Config.cmake.in
index 0229c033..867a3535 100644
--- a/xo-procedure2/cmake/xo_procedure2Config.cmake.in
+++ b/xo-procedure2/cmake/xo_procedure2Config.cmake.in
@@ -6,6 +6,7 @@ include(CMakeFindDependencyMacro)
 #       must coordinate with xo_dependency() calls
 #       in CMakeLists.txt
 #
+find_dependency(xo_object2)
 find_dependency(xo_gc)
 find_dependency(subsys)
 
diff --git a/xo-procedure2/idl/IGCObject_DPrimitive_gco_2_gco_gco.json5 b/xo-procedure2/idl/IGCObject_DPrimitive_gco_2_gco_gco.json5
new file mode 100644
index 00000000..b2fb4014
--- /dev/null
+++ b/xo-procedure2/idl/IGCObject_DPrimitive_gco_2_gco_gco.json5
@@ -0,0 +1,16 @@
+{
+    mode: "implementation",
+    includes: [
+        //<xo/procedure2/GCObjectConversion_DPrimitive_gco_2_gco_gco.hpp>
+        "<xo/gc/GCObject.hpp>",
+        "<xo/alloc2/Allocator.hpp>",
+    ],
+    local_types: [ ],
+    namespace1: "xo",
+    namespace2: "scm",
+    facet_idl: "idl/GCObject.json5",
+    brief: "provide AGCobject interface for Primitive (gco x gco) -> gco",
+    using_doxygen: true,
+    repr: "DPrimitive_gco_2_gco_gco",
+    doc: [ "implement AGCObject for DPrimitive (gco x gco) -> gco" ],
+}
diff --git a/xo-procedure2/include/xo/procedure2/DPrimitive.hpp b/xo-procedure2/include/xo/procedure2/DPrimitive.hpp
index afd2ada2..c225246d 100644
--- a/xo-procedure2/include/xo/procedure2/DPrimitive.hpp
+++ b/xo-procedure2/include/xo/procedure2/DPrimitive.hpp
@@ -58,6 +58,7 @@ namespace xo {
         template <typename Fn>
         class Primitive {
         public:
+            using ACollector = xo::mm::ACollector;
             using AAllocator = xo::mm::AAllocator;
             using AGCObject = xo::mm::AGCObject;
             using DArray = xo::scm::DArray;
@@ -74,6 +75,13 @@ namespace xo {
                                       std::make_index_sequence<Traits::n_args>{});
             }
 
+            /** @defgroup scm-primitive-gcobject-facet **/
+            ///@{
+            std::size_t shallow_size() const noexcept;
+            Primitive * shallow_copy(obj<AAllocator> mm) const noexcept;
+            std::size_t forward_children(obj<ACollector> gc) noexcept;
+            ///@}
+
         private:
             template <std::size_t... Is>
             obj<AGCObject> _apply_nocheck(obj<ARuntimeContext> rcx,
@@ -103,6 +111,31 @@ namespace xo {
             Fn fn_;
         }; /*Primitive*/
 
+        template <typename Fn>
+        std::size_t
+        Primitive<Fn>::shallow_size() const noexcept {
+            return sizeof(*this);
+        }
+
+        template <typename Fn>
+        Primitive<Fn> *
+        Primitive<Fn>::shallow_copy(obj<AAllocator> mm) const noexcept {
+            void * mem = mm.alloc_copy((std::byte *)this);
+
+            if (mem) {
+                return new (mem) Primitive(*this);
+            }
+
+            return nullptr;
+        }
+
+        template <typename Fn>
+        std::size_t
+        Primitive<Fn>::forward_children(obj<ACollector>) noexcept {
+            // Primitive holds no GC refs (just string_view + function pointer)
+            return this->shallow_size();
+        }
+
     } /*namespace scm*/
 } /*namespace xo*/
 
diff --git a/xo-procedure2/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_gco_gco.hpp b/xo-procedure2/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_gco_gco.hpp
new file mode 100644
index 00000000..344aa6c1
--- /dev/null
+++ b/xo-procedure2/include/xo/procedure2/detail/IGCObject_DPrimitive_gco_2_gco_gco.hpp
@@ -0,0 +1,67 @@
+/** @file IGCObject_DPrimitive_gco_2_gco_gco.hpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [/home/roland/proj/xo-umbrella2-claude1/xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/IGCObject_DPrimitive_gco_2_gco_gco.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_repr.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/IGCObject_DPrimitive_gco_2_gco_gco.json5]
+ **/
+
+#pragma once
+
+#include "GCObject.hpp"
+#include <xo/gc/GCObject.hpp>
+#include <xo/alloc2/Allocator.hpp>
+#include "DPrimitive_gco_2_gco_gco.hpp"
+
+namespace xo { namespace scm { class IGCObject_DPrimitive_gco_2_gco_gco; } }
+
+namespace xo {
+    namespace facet {
+        template <>
+        struct FacetImplementation<xo::mm::AGCObject,
+                                   xo::scm::DPrimitive_gco_2_gco_gco>
+        {
+            using ImplType = xo::mm::IGCObject_Xfer
+              <xo::scm::DPrimitive_gco_2_gco_gco,
+               xo::scm::IGCObject_DPrimitive_gco_2_gco_gco>;
+        };
+    }
+}
+
+namespace xo {
+    namespace scm {
+        /** @class IGCObject_DPrimitive_gco_2_gco_gco
+         **/
+        class IGCObject_DPrimitive_gco_2_gco_gco {
+        public:
+            /** @defgroup scm-gcobject-dprimitive_gco_2_gco_gco-type-traits **/
+            ///@{
+            using size_type = xo::mm::AGCObject::size_type;
+            using AAllocator = xo::mm::AGCObject::AAllocator;
+            using ACollector = xo::mm::AGCObject::ACollector;
+            using Copaque = xo::mm::AGCObject::Copaque;
+            using Opaque = xo::mm::AGCObject::Opaque;
+            ///@}
+            /** @defgroup scm-gcobject-dprimitive_gco_2_gco_gco-methods **/
+            ///@{
+            // const methods
+            /** memory consumption for this instance **/
+            static size_type shallow_size(const DPrimitive_gco_2_gco_gco & self) noexcept;
+            /** copy instance using allocator **/
+            static Opaque shallow_copy(const DPrimitive_gco_2_gco_gco & self, obj<AAllocator> mm) noexcept;
+
+            // non-const methods
+            /** during GC: forward immdiate children **/
+            static size_type forward_children(DPrimitive_gco_2_gco_gco & self, obj<ACollector> gc) noexcept;
+            ///@}
+        };
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end */
\ No newline at end of file
diff --git a/xo-procedure2/include/xo/procedure2/init_primitives.hpp b/xo-procedure2/include/xo/procedure2/init_primitives.hpp
index 5e2d08e8..48b733df 100644
--- a/xo-procedure2/include/xo/procedure2/init_primitives.hpp
+++ b/xo-procedure2/include/xo/procedure2/init_primitives.hpp
@@ -7,12 +7,19 @@
 
 namespace xo {
     namespace scm {
+/** TODO: move this into xo-reader2 ? **/
+
 #ifdef NOT_YET
         using Primitive_f64_1_f64 = Primitive<double (*)(double)>;
         using Primitive_f64_2_f64_f64 = Primitive<double (*)(double, double)>;
 #endif
 
         struct Primitives {
+            /** polymorphich multiply
+             *
+             *  TODO: this will want to move to xo-numeric/
+             *        so we can dispatch on vector, matrix, function types
+             **/
             static DPrimitive_gco_2_gco_gco s_mul_gco_gco_pm;
 
 #ifdef NOT_YET
diff --git a/xo-procedure2/src/procedure2/CMakeLists.txt b/xo-procedure2/src/procedure2/CMakeLists.txt
index 11a9c305..c127b760 100644
--- a/xo-procedure2/src/procedure2/CMakeLists.txt
+++ b/xo-procedure2/src/procedure2/CMakeLists.txt
@@ -7,6 +7,7 @@ set(SELF_SRCS
     DPrimitive.cpp
     IRuntimeContext_Any.cpp
     IProcedure_Any.cpp
+    IGCObject_DPrimitive_gco_2_gco_gco.cpp
     IProcedure_DPrimitive_gco_2_gco_gco.cpp
     # Add source files here, e.g.:
     # procedure2.cpp
diff --git a/xo-procedure2/src/procedure2/IGCObject_DPrimitive_gco_2_gco_gco.cpp b/xo-procedure2/src/procedure2/IGCObject_DPrimitive_gco_2_gco_gco.cpp
new file mode 100644
index 00000000..bd88e9ff
--- /dev/null
+++ b/xo-procedure2/src/procedure2/IGCObject_DPrimitive_gco_2_gco_gco.cpp
@@ -0,0 +1,39 @@
+/** @file IGCObject_DPrimitive_gco_2_gco_gco.cpp
+ *
+ *  Generated automagically from ingredients:
+ *  1. code generator:
+ *       [/home/roland/proj/xo-umbrella2-claude1/xo-facet/codegen/genfacet]
+ *     arguments:
+ *       --input [idl/IGCObject_DPrimitive_gco_2_gco_gco.json5]
+ *  2. jinja2 template for abstract facet .hpp file:
+ *       [iface_facet_any.hpp.j2]
+ *  3. idl for facet methods
+ *       [idl/IGCObject_DPrimitive_gco_2_gco_gco.json5]
+**/
+
+#include "detail/IGCObject_DPrimitive_gco_2_gco_gco.hpp"
+
+namespace xo {
+    namespace scm {
+        auto
+        IGCObject_DPrimitive_gco_2_gco_gco::shallow_size(const DPrimitive_gco_2_gco_gco & self) noexcept -> size_type
+        {
+            return self.shallow_size();
+        }
+
+        auto
+        IGCObject_DPrimitive_gco_2_gco_gco::shallow_copy(const DPrimitive_gco_2_gco_gco & self, obj<AAllocator> mm) noexcept -> Opaque
+        {
+            return self.shallow_copy(mm);
+        }
+
+        auto
+        IGCObject_DPrimitive_gco_2_gco_gco::forward_children(DPrimitive_gco_2_gco_gco & self, obj<ACollector> gc) noexcept -> size_type
+        {
+            return self.forward_children(gc);
+        }
+
+    } /*namespace scm*/
+} /*namespace xo*/
+
+/* end IGCObject_DPrimitive_gco_2_gco_gco.cpp */
\ No newline at end of file