diff --git a/doc/guix.texi b/doc/guix.texi
index 9d9d2aa083d..9088cb40d71 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -9433,6 +9433,7 @@ the libraries and header files are assumed to be host tools.
 @defvar asdf-build-system/source
 @defvarx asdf-build-system/sbcl
 @defvarx asdf-build-system/ecl
+@defvarx asdf-build-system/clasp
 
 These variables, exported by @code{(guix build-system asdf)}, implement
 build procedures for Common Lisp packages using