diff --git a/lib/libc/sys/open.2 b/lib/libc/sys/open.2
index 41951cefafe..20f0c426b66 100644
--- a/lib/libc/sys/open.2
+++ b/lib/libc/sys/open.2
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: open.2,v 1.56 2026/04/01 02:32:49 jsg Exp $
+.\"	$OpenBSD: open.2,v 1.57 2026/04/08 11:36:40 jsg Exp $
 .\"	$NetBSD: open.2,v 1.8 1995/02/27 12:35:14 cgd Exp $
 .\"
 .\" Copyright (c) 1980, 1991, 1993
@@ -30,7 +30,7 @@
 .\"
 .\"     @(#)open.2	8.2 (Berkeley) 11/16/93
 .\"
-.Dd $Mdocdate: April 1 2026 $
+.Dd $Mdocdate: April 8 2026 $
 .Dt OPEN 2
 .Os
 .Sh NAME
@@ -301,6 +301,8 @@ it is to be opened for writing.
 The
 .Fa flags
 specified for opening the file are not valid.
+.It Bq Er EINVAL
+O_CREAT and O_DIRECTORY were specified.
 .It Bq Er EROFS
 The named file resides on a read-only file system,
 and the file is to be modified.