Index: src/routes/activitypub.js
===================================================================
--- src/routes/activitypub.js	(revision f3caf194e5257640279bb1d13500358ff4965402)
+++ src/routes/activitypub.js	(revision 6bc2e31be027c19ca280d49b79711d4e4a1952db)
@@ -191,4 +191,8 @@
         emojis: (() => { try { return t.reblog_emoji_json ? JSON.parse(t.reblog_emoji_json) : undefined; } catch { return undefined; } })(),
       } : undefined,
+      // Whether THIS account already liked/boosted the note, so the app's
+      // detail-view buttons show the current state (and can toggle/undo).
+      'shaer:liked': !!t.liked,
+      'shaer:boosted': !!t.boosted,
     },
   }));