diff --git a/data/event-schemas/schema/m.room.pinned_events.yaml b/data/event-schemas/schema/m.room.pinned_events.yaml
index e4206ade..4e5ea1a9 100644
--- a/data/event-schemas/schema/m.room.pinned_events.yaml
+++ b/data/event-schemas/schema/m.room.pinned_events.yaml
@@ -11,6 +11,8 @@ properties:
         description: An ordered list of event IDs to pin.
         items:
           type: string
+          format: mx-event-id
+          pattern: "^$"
         type: array
     required:
       - pinned