diff --git a/packages/backend/src/remote/activitypub/renderer/note.ts b/packages/backend/src/remote/activitypub/renderer/note.ts
index b3bafaa3a..3e802fe03 100644
--- a/packages/backend/src/remote/activitypub/renderer/note.ts
+++ b/packages/backend/src/remote/activitypub/renderer/note.ts
@@ -132,6 +132,7 @@ export default async function renderNote(note: Note, dive = true, isTalk = false
 
 	return {
 		id: `${config.url}/notes/${note.id}`,
+		context: `${config.url}/notes/${note.threadId}`,
 		type: 'Note',
 		attributedTo,
 		summary,