diff --git a/npa/src/npa-tool.ggo.in b/npa/src/npa-tool.ggo.in
index 2df8c08..6883877 100644
--- a/npa/src/npa-tool.ggo.in
+++ b/npa/src/npa-tool.ggo.in
@@ -43,6 +43,7 @@ section "PIN management"
 option "new-pin"        N
     "Install a new PIN"
     string
+    argoptional
     optional
 option "resume"         R
     "Resume eID-PIN (uses CAN to activate last retry)"