diff --git a/parsers/src/sm.rs b/parsers/src/sm.rs
index e018e6fde5f24b6a5602dd12428f055d0acbc6ef..d9e1996250cd7a40b5bcb827ca7f60cb7f6c5cf8 100644
--- a/parsers/src/sm.rs
+++ b/parsers/src/sm.rs
@@ -139,7 +139,7 @@ pub struct Resumed {
 #[xml(namespace = ns::SM, name = "sm")]
 pub struct StreamManagement {
     /// `<optional/>` flag.
-    #[xml(flag(name = "optional"))]
+    #[xml(flag)]
     pub optional: bool,
 }
 
diff --git a/parsers/src/starttls.rs b/parsers/src/starttls.rs
index 182537ac1a0e43d35260da10e53ac9a57a22f392..92b156f2d1235856002a79af11b6f3382ba0bea5 100644
--- a/parsers/src/starttls.rs
+++ b/parsers/src/starttls.rs
@@ -25,7 +25,7 @@ pub struct Proceed;
 #[xml(namespace = ns::TLS, name = "starttls")]
 pub struct StartTls {
     /// Marker for mandatory StartTLS.
-    #[xml(flag(name = "required"))]
+    #[xml(flag)]
     pub required: bool,
 }
 
diff --git a/parsers/src/util/macro_tests.rs b/parsers/src/util/macro_tests.rs
index 98bc0a8ea199f510f88ac30430f58d7c519517ac..918f00b4b1d411955d55ace8da5130919a822681 100644
--- a/parsers/src/util/macro_tests.rs
+++ b/parsers/src/util/macro_tests.rs
@@ -1977,7 +1977,7 @@ fn extract_ignore_unknown_stuff_roundtrip() {
 #[derive(FromXml, AsXml, PartialEq, Debug, Clone)]
 #[xml(namespace = NS1, name = "foo")]
 struct Flag {
-    #[xml(flag(namespace = NS1, name = "flag"))]
+    #[xml(flag)]
     flag: bool,
 }
 
diff --git a/xso-proc/src/meta.rs b/xso-proc/src/meta.rs
index 43e7af5489a6bd4acba5e7c07f12ea6e5f40afe5..8018d15a4e8d15fa8db141469d92c7aec7611f96 100644
--- a/xso-proc/src/meta.rs
+++ b/xso-proc/src/meta.rs
@@ -1055,10 +1055,12 @@ impl XmlFieldMeta {
     /// Parse a `#[xml(flag)]` meta.
     fn flag_from_meta(meta: ParseNestedMeta<'_>) -> Result<Self> {
         let mut qname = QNameRef::default();
-        meta.parse_nested_meta(|meta| match qname.parse_incremental_from_meta(meta)? {
-            None => Ok(()),
-            Some(meta) => Err(Error::new_spanned(meta.path, "unsupported key")),
-        })?;
+        if meta.input.peek(syn::token::Paren) {
+            meta.parse_nested_meta(|meta| match qname.parse_incremental_from_meta(meta)? {
+                None => Ok(()),
+                Some(meta) => Err(Error::new_spanned(meta.path, "unsupported key")),
+            })?;
+        }
         Ok(Self::Flag {
             span: meta.path.span(),
             qname,