diff --git a/src/lib/nostrUtils.test.ts b/src/lib/nostrUtils.test.ts
index b18c721..afe93c8 100644
--- a/src/lib/nostrUtils.test.ts
+++ b/src/lib/nostrUtils.test.ts
@@ -26,6 +26,21 @@ describe('isReply', () => {
   it('is true for a note using the deprecated positional e tag', () => {
     expect(isReply(note([['e', 'parent-id']]))).toBe(true);
   });
+
+  it('is false for a note that only mentions another event', () => {
+    expect(isReply(note([['e', 'mentioned-id', '', 'mention']]))).toBe(false);
+  });
+
+  it('is true for a note with a mention alongside a marked reply', () => {
+    expect(
+      isReply(
+        note([
+          ['e', 'root-id', '', 'root'],
+          ['e', 'mentioned-id', '', 'mention'],
+        ]),
+      ),
+    ).toBe(true);
+  });
 });
 
 describe('rootReference', () => {
diff --git a/src/lib/nostrUtils.ts b/src/lib/nostrUtils.ts
index 7b1247d..7477925 100644
--- a/src/lib/nostrUtils.ts
+++ b/src/lib/nostrUtils.ts
@@ -93,7 +93,8 @@ export function tagValues(event: NostrEvent, name: string): string[] {
 
 /**
  * The event a reply points at, following NIP-10: prefer an explicit `root`
- * marker, fall back to the last positional `e` tag.
+ * marker, fall back to the first positional `e` tag (the deprecated scheme
+ * puts the root id first: `["e", <root-id>], ["e", <reply-id>]`).
  */
 export function rootReference(event: NostrEvent): string | undefined {
   const marked = event.tags.find(([name, , , marker]) => name === 'e' && marker === 'root');
@@ -102,6 +103,12 @@ export function rootReference(event: NostrEvent): string | undefined {
   return positional[0]?.[1];
 }
 
+/**
+ * True for a reply per NIP-10: a marked `root`/`reply` `e` tag, or an
+ * unmarked one (the deprecated positional scheme). An `e` tag marked
+ * `mention` alone does not make an event a reply — it cites another event
+ * without being part of its thread.
+ */
 export function isReply(event: NostrEvent): boolean {
-  return event.tags.some(([name]) => name === 'e');
+  return event.tags.some(([name, , , marker]) => name === 'e' && marker !== 'mention');
 }