diff --git a/src/blackboard/db.py b/src/blackboard/db.py
index 05c0344..a8ebe5b 100644
--- a/src/blackboard/db.py
+++ b/src/blackboard/db.py
@@ -294,10 +294,12 @@ _SCHEMA_STATEMENTS = [
         agent TEXT,
         event_type TEXT NOT NULL,
         detail TEXT,
+        card_id TEXT DEFAULT 'default',
         created_at TEXT NOT NULL DEFAULT (datetime('now'))
     )""",
     "CREATE INDEX IF NOT EXISTS idx_events_task ON events(task_id)",
     "CREATE INDEX IF NOT EXISTS idx_events_time ON events(created_at)",
+    "CREATE INDEX IF NOT EXISTS idx_events_card ON events(card_id)",
 
     # agents
     """CREATE TABLE IF NOT EXISTS agents (