diff --git a/src/callint.c b/src/callint.c
index 04bd64535c9..d8d2b278458 100644
--- a/src/callint.c
+++ b/src/callint.c
@@ -105,13 +105,12 @@ If the string begins with `^' and `shift-select-mode' is non-nil,
 You may use `@', `*', and `^' together.  They are processed in the
  order that they appear, before reading any arguments.
 
-If MODES is present, it should be a list of mode names (symbols) that
-this command is applicable for.  The main effect of this is that
-`M-x TAB' will be able to exclude this command from the list of
-completion candidates if the current buffer's mode doesn't match the list.
-That is, if either the major mode isn't derived from them, or (when it's
-a minor mode) the mode isn't in effect.  Which commands are excluded
-from the list of completion candidates is controlled by the value
+If MODES is present, it should be one or more mode names (symbols)
+for which this command is applicable.  This is so that `M-x TAB'
+will be able to exclude this command from the list of completion
+candidates if the current buffer's mode doesn't match the list.
+Which commands are excluded from the list of completion
+candidates based on this information is controlled by the value
 of `read-extended-command-predicate', which see.
 
 usage: (interactive &optional ARG-DESCRIPTOR &rest MODES)  */