diff --git a/cmd/tailscale/cli/up.go b/cmd/tailscale/cli/up.go
index 5d2916f27..e7586690e 100644
--- a/cmd/tailscale/cli/up.go
+++ b/cmd/tailscale/cli/up.go
@@ -46,8 +46,10 @@
 
 If flags are specified, the flags must be the complete set of desired
 settings. An error is returned if any setting would be changed as a
-result of an unspecified flag's default value, unless the --reset
-flag is also used.
+result of an unspecified flag's default value, unless the --reset flag
+is also used. (The flags --authkey, --force-reauth, and --qr are not
+considered settings that need to be re-specified when modifying
+settings.)
 `),
 	FlagSet: upFlagSet,
 	Exec:    runUp,