diff --git a/src/lib/notifications/__tests__/reminder-dedup.test.ts b/src/lib/notifications/__tests__/reminder-dedup.test.ts
new file mode 100644
index 000000000..415f0e5b1
--- /dev/null
+++ b/src/lib/notifications/__tests__/reminder-dedup.test.ts
@@ -0,0 +1,66 @@
+import { beforeEach, describe, expect, it, vi } from "vitest";
+
+import { prisma } from "@/lib/db";
+
+const findFirstMock = vi.fn();
+const createMock = vi.fn();
+
+vi.mock("@/lib/db", () => ({
+  prisma: {
+    notificationEvent: {
+      findFirst: (...args: unknown[]) => findFirstMock(...args),
+      create: (...args: unknown[]) => createMock(...args),
+    },
+  },
+}));
+
+import {
+  hasReminderDedupAnchor,
+  writeReminderDedupAnchor,
+} from "../reminder-dedup";
+
+beforeEach(() => {
+  findFirstMock.mockReset().mockResolvedValue(null);
+  createMock.mockReset().mockResolvedValue({ id: "event" });
+});
+
+describe("reminder dedup anchors", () => {
+  it("looks up a record-scoped event rather than a delivery attempt", async () => {
+    const now = new Date("2026-08-06T08:00:00.000Z");
+
+    await expect(
+      hasReminderDedupAnchor(prisma as never, {
+        userId: "managed-record",
+        eventType: "MEDICATION_REMINDER",
+        reason: "med:slot",
+        now,
+      }),
+    ).resolves.toBe(false);
+
+    expect(findFirstMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        where: expect.objectContaining({
+          recordUserId: "managed-record",
+          eventType: "MEDICATION_REMINDER",
+          dedupKey: "med:slot",
+        }),
+      }),
+    );
+  });
+
+  it("writes an append-only record event without inventing a recipient", async () => {
+    await writeReminderDedupAnchor(prisma as never, {
+      userId: "managed-record",
+      eventType: "MEDICATION_REMINDER",
+      reason: "med:slot",
+    });
+
+    expect(createMock).toHaveBeenCalledWith({
+      data: {
+        recordUserId: "managed-record",
+        eventType: "MEDICATION_REMINDER",
+        dedupKey: "med:slot",
+      },
+    });
+  });
+});