Index: src/routes/posts.js
===================================================================
--- src/routes/posts.js	(revision 328d83725a5461bae2e5639ede37cbe4cf206b67)
+++ src/routes/posts.js	(revision 69b509deb1cd2e740430a5032713f538d22e90d9)
@@ -169,4 +169,33 @@
 
 // ==================== CREATE POST ====================
+// ── Per-post audio federation ──────────────────────────────────────────────
+// "Share audio on the fediverse" is a per-post choice in the editor, but the underlying
+// flag is per track (audio_tracks.fedi_open — it gates the file + drives the AS2 Audio
+// attachment). NB: the file gate is per file, so opening a track in one post makes its file
+// fetchable for every post that reuses it.
+function setAudioFediOpen(siteId, content, open) {
+  const val = open ? 1 : 0;
+  const c = content || '';
+  try {
+    for (const m of c.matchAll(/\[\[track:([A-Za-z0-9_-]+)\]\]/g)) db.prepare('UPDATE audio_tracks SET fedi_open = ? WHERE id = ? AND site_id = ?').run(val, m[1], siteId);
+    for (const m of c.matchAll(/\[\[album:([^\]]+)\]\]/g)) db.prepare('UPDATE audio_tracks SET fedi_open = ? WHERE site_id = ? AND album = ?').run(val, siteId, m[1].trim());
+    for (const m of c.matchAll(/\[\[playlist:([A-Za-z0-9_-]+)\]\]/g)) db.prepare('UPDATE audio_tracks SET fedi_open = ? WHERE id IN (SELECT track_id FROM playlist_tracks WHERE playlist_id = ?)').run(val, m[1]);
+  } catch { /* non-fatal */ }
+}
+// True when the post references hosted audio AND all of it is currently fedi_open (drives the
+// editor checkbox's initial state).
+function postAudioFediOpen(siteId, content) {
+  const c = content || '';
+  if (!/\[\[(track|album|playlist):/i.test(c)) return false;
+  let total = 0, open = 0;
+  const tally = (r) => { if (r && r.media_id) { total++; if (r.fedi_open) open++; } };
+  try {
+    for (const m of c.matchAll(/\[\[track:([A-Za-z0-9_-]+)\]\]/g)) tally(db.prepare('SELECT fedi_open, media_id FROM audio_tracks WHERE id = ? AND site_id = ?').get(m[1], siteId));
+    for (const m of c.matchAll(/\[\[album:([^\]]+)\]\]/g)) for (const r of db.prepare('SELECT fedi_open, media_id FROM audio_tracks WHERE site_id = ? AND album = ? AND media_id IS NOT NULL').all(siteId, m[1].trim())) tally(r);
+    for (const m of c.matchAll(/\[\[playlist:([A-Za-z0-9_-]+)\]\]/g)) for (const r of db.prepare('SELECT t.fedi_open, t.media_id FROM playlist_tracks pt JOIN audio_tracks t ON t.id = pt.track_id WHERE pt.playlist_id = ? AND t.media_id IS NOT NULL').all(m[1])) tally(r);
+  } catch { /* non-fatal */ }
+  return total > 0 && open === total;
+}
+
 router.post('/posts/create', requireAuth, (req, res) => {
   const site = res.locals.site;
@@ -228,4 +257,8 @@
   );
 
+  // Per-post "share audio on the fediverse" → set fedi_open on this post's hosted tracks
+  // BEFORE federating, so the Create note carries the right Audio attachments.
+  setAudioFediOpen(site.id, cleanContent, req.body.fedi_open_audio);
+
   if (finalStatus === 'published') {
     try {
@@ -278,4 +311,5 @@
     post,
     isNew: false,
+    fediOpenAudio: postAudioFediOpen(site.id, post.content),
     pageTitle: 'Edit: ' + (post.title || 'Untitled'),
     bodyClass: 'on-special',
@@ -349,4 +383,8 @@
     finalSlug, publishedAt, now, post.id
   );
+
+  // Per-post "share audio on the fediverse" → set fedi_open on this post's hosted tracks
+  // BEFORE federating, so the Update/Create note carries the right Audio attachments.
+  setAudioFediOpen(site.id, cleanContent, req.body.fedi_open_audio);
 
   // Update FTS