diff --git a/lib/libc/sys/ptrace.2 b/lib/libc/sys/ptrace.2
--- a/lib/libc/sys/ptrace.2
+++ b/lib/libc/sys/ptrace.2
@@ -164,17 +164,22 @@
 .Fn ptrace
 requests from targeting processes with the real user identifier different
 from the real user identifier of the caller.
-The requests return
-.Er ESRCH
-if policy is not met.
+These requests will fail with error
+.Er ESRCH .
 .It Dv security.bsd.see_other_gids
 Setting this sysctl to zero value disallows
 .Fn ptrace
-requests from process belonging to a group that is not also one of
-the group of the target process.
-The requests return
-.Er ESRCH
-if policy is not met.
+requests from processes belonging to a group that is not also one of the group
+of the target process.
+These requests will fail with error
+.Er ESRCH .
+.It Dv security.bsd.see_jail_proc
+Setting this sysctl to zero value disallows
+.Fn ptrace
+requests from processes belonging to a different jail than that of the target
+process, even if the former jail is an ancestor of the latter.
+These requests will fail with error
+.Er ESRCH .
 .It Dv securelevel and init
 The
 .Xr init 1