diff --git a/cmd/root.go b/cmd/root.go
index 4915e2b..44dc095 100644
--- a/cmd/root.go
+++ b/cmd/root.go
@@ -72,7 +72,8 @@ func maybeDefaultToSpeak() {
 
 func isCobraBuiltin(name string) bool {
 	name = strings.ToLower(name)
-	return name == "help" || name == "completion"
+	return name == "help" || name == "completion" ||
+		name == "__complete" || name == "__completenodesc"
 }
 
 func isKnownSubcommand(name string) bool {
diff --git a/cmd/root_test.go b/cmd/root_test.go
index 2ad30c8..8536da1 100644
--- a/cmd/root_test.go
+++ b/cmd/root_test.go
@@ -43,6 +43,8 @@ func TestMaybeDefaultToSpeak_Builtins(t *testing.T) {
 	cases := [][]string{
 		{"sag", "help"},
 		{"sag", "completion"},
+		{"sag", "__complete"},
+		{"sag", "__completeNoDesc"},
 	}
 	for _, args := range cases {
 		t.Run(args[1], func(t *testing.T) {