diff --git a/module/ice-9/session.scm b/module/ice-9/session.scm
index fbb03d2..dc2c927 100644
--- a/module/ice-9/session.scm
+++ b/module/ice-9/session.scm
@@ -504,13 +504,14 @@ It is an image under the mapping EXTRACT."
 if the information cannot be obtained.
 
 The alist keys that are currently defined are `required', `optional',
-`keyword', and `rest'."
+`keyword', allow-other-keys? and `rest'."
   (cond
    ((procedure-property proc 'arglist)
     => (lambda (arglist)
          `((required . ,(car arglist))
            (optional . ,(cadr arglist))
            (keyword . ,(caddr arglist))
+           (allow-other-keys? . ,(cadddr arglist))
            (rest . ,(car (cddddr arglist))))))
    ((procedure-source proc)
     => cadr)