diff --git a/bindings/ldk_node.udl b/bindings/ldk_node.udl
index db6a127c4..8ffafff2c 100644
--- a/bindings/ldk_node.udl
+++ b/bindings/ldk_node.udl
@@ -237,6 +237,7 @@ interface PaymentKind {
 	Onchain();
 	Bolt11(PaymentHash hash, PaymentPreimage? preimage, PaymentSecret? secret, string? bolt11_invoice);
 	Bolt11Jit(PaymentHash hash, PaymentPreimage? preimage, PaymentSecret? secret, LSPFeeLimits lsp_fee_limits);
+	// TODO: add custom_tlvs here as sequence<TlvEntry> custom_tlvs
 	Spontaneous(PaymentHash hash, PaymentPreimage? preimage);
 };