diff --git a/source/exec.tex b/source/exec.tex
index e1870a2de9..c398ceec8a 100644
--- a/source/exec.tex
+++ b/source/exec.tex
@@ -530,6 +530,9 @@
   // \ref{exec.snd}, senders
   struct @\libglobal{sender_t}@ {};
 
+  template<class Sndr>
+    inline constexpr bool enable_sender = @\seebelow@;
+
   template<class Sndr>
     concept @\libconcept{sender}@ = @\seebelow@;