diff --git a/modules/lang/common-lisp/doctor.el b/modules/lang/common-lisp/doctor.el
new file mode 100644
index 000000000..891f5ae8e
--- /dev/null
+++ b/modules/lang/common-lisp/doctor.el
@@ -0,0 +1,6 @@
+;;; lang/common-lisp/doctor.el -*- lexical-binding: t; -*-
+
+(when (require 'sly nil t)
+  (unless (executable-find inferior-lisp-program)
+    (warn! "Couldn't find your `inferior-lisp-program' (%s). Is it installed?"
+           inferior-lisp-program)))