diff --git a/apps/api/src/routes/events.ts b/apps/api/src/routes/events.ts
index 3a795cc..e85c19c 100644
--- a/apps/api/src/routes/events.ts
+++ b/apps/api/src/routes/events.ts
@@ -256,11 +256,17 @@ eventsRouter.post('/create', zValidator('json', eventFieldsSchema), async (c) =>
       }
       targetCalendarUrl = calRow.url
     } else {
-      // Default to first personal calendar (D-01)
+      // Default to the member's first personal calendar (D-01).
+      // WR-02: add a deterministic ORDER BY + LIMIT. Without them, a member with
+      // multiple personal calendars gets an arbitrary, query-to-query-unstable "first"
+      // row. Ordering by id (insertion order) gives a stable default; limit(1) avoids
+      // fetching the whole set just to take [0].
       const [calRow] = await db
         .select({ url: calendars.url })
         .from(calendars)
         .where(eq(calendars.userId, currentUserId))
+        .orderBy(calendars.id)
+        .limit(1)
 
       if (!calRow) {
         return c.json({ error: 'No writable calendar found for user' }, 422)