diff --git a/codegen/genfacet b/codegen/genfacet
index c20689d..8edadc1 100755
--- a/codegen/genfacet
+++ b/codegen/genfacet
@@ -314,6 +314,8 @@ def gen_facet_impl(env,
     router_facet = f'R{facet_name}'
     # RFoo.hpp
     router_facet_hpp_fname = f'{router_facet}.hpp'
+    # user defined content -- whatever you want
+    router_facet_explicit_content = facet_idl['router_facet_explicit_content']
 
     # ================================================================
     # vars for IFacet_DRepr
@@ -384,6 +386,7 @@ def gen_facet_impl(env,
         'router_facet': router_facet,
         'router_facet_hpp_j2': 'router_facet.hpp.j2',
         'router_facet_hpp_fname': router_facet_hpp_fname,
+        'router_facet_explicit_content': router_facet_explicit_content,
         #
         'types': facet_types,
         'local_types': local_types,
diff --git a/codegen/router_facet.hpp.j2 b/codegen/router_facet.hpp.j2
index 5c3f649..ca8d640 100644
--- a/codegen/router_facet.hpp.j2
+++ b/codegen/router_facet.hpp.j2
@@ -56,6 +56,11 @@ public:
     ///@{
     {% endif %}
 
+    // explicit injected content
+    {% for c in router_facet_explicit_content %}
+    {{c}}
+    {% endif %}
+
     // builtin methods
     typeseq _typeseq() const noexcept { return O::iface()->_typeseq(); }
     void _drop() const noexcept { O::iface()->_drop(O::data()); }