diff --git a/apps/bot/src/scheduler/reminder-jobs.test.ts b/apps/bot/src/scheduler/reminder-jobs.test.ts
new file mode 100644
index 0000000..af0360e
--- /dev/null
+++ b/apps/bot/src/scheduler/reminder-jobs.test.ts
@@ -0,0 +1,119 @@
+import { describe, it, expect, vi, beforeEach } from "vitest";
+
+// pg-boss + db mocks. Hoisted so the vi.mock factories below can refer
+// to the spies — see https://vitest.dev/api/vi.html#vi-hoisted.
+const {
+  bossSendMock,
+  dbExecuteMock,
+} = vi.hoisted(() => ({
+  bossSendMock: vi.fn(async (..._args: unknown[]) => "new-job-id"),
+  dbExecuteMock: vi.fn(async (..._args: unknown[]) => ({ rows: [] as unknown[] })),
+}));
+
+vi.mock("../db.js", () => ({
+  db: { execute: (...a: unknown[]) => dbExecuteMock(...a) },
+}));
+vi.mock("../logger.js", () => ({
+  logger: { info: vi.fn(), warn: vi.fn(), error: vi.fn() },
+}));
+
+// We don't import pg-boss directly — scheduleReminderFire receives a
+// PgBoss instance as its first arg. Build a minimal stub that exposes
+// just the .send method (and createQueue / work for registerReminderJobs
+// if we ever wire it here).
+const fakeBoss = {
+  send: bossSendMock,
+} as unknown as Parameters<typeof scheduleReminderFire>[0];
+
+import { scheduleReminderFire } from "./reminder-jobs.js";
+
+const REMINDER_ID = "11111111-1111-1111-1111-111111111111";
+const SINGLETON_KEY = `reminder:${REMINDER_ID}`;
+const FIRE_AT = new Date("2026-05-10T12:20:00.000Z");
+
+beforeEach(() => {
+  bossSendMock.mockReset();
+  bossSendMock.mockResolvedValue("new-job-id");
+  dbExecuteMock.mockReset();
+  dbExecuteMock.mockResolvedValue({ rows: [] });
+});
+
+describe("scheduleReminderFire — pre-send cancel of stale created jobs", () => {
+  it("ALWAYS runs the cancel-stale UPDATE before boss.send (regression: stately dedupe dropped reschedules)", async () => {
+    // Repro of the dropped-fire bug: the queue was on policy=stately
+    // and a prior schedule had left a 'created' job in pg-boss with
+    // the same singletonKey. The new send returned null and the
+    // user's 8:20 PM fire was silently lost. Under the fix, we MUST
+    // tombstone any prior created jobs FIRST so the new send wins
+    // even under standard policy.
+    dbExecuteMock.mockResolvedValueOnce({ rows: [{ id: "stale-1" }] });
+    const result = await scheduleReminderFire(fakeBoss, REMINDER_ID, FIRE_AT);
+    // Order matters: cancel happens before send.
+    expect(dbExecuteMock).toHaveBeenCalledTimes(1);
+    expect(bossSendMock).toHaveBeenCalledTimes(1);
+    expect(dbExecuteMock.mock.invocationCallOrder[0]).toBeLessThan(
+      bossSendMock.mock.invocationCallOrder[0]!,
+    );
+    expect(result).toBe("new-job-id");
+  });
+
+  it("scopes the cancel to state='created' only — active/completed jobs MUST survive", async () => {
+    // The cancel must NOT touch in-flight runs (state='active') nor
+    // historical fires (state='completed'). Otherwise we'd nuke the
+    // run that's currently sending and the user gets phantom 'failed'
+    // rows in the activity feed.
+    await scheduleReminderFire(fakeBoss, REMINDER_ID, FIRE_AT);
+    const sqlStmt = dbExecuteMock.mock.calls[0]![0];
+    // Drizzle's sql template returns an SQL object; serialise to inspect.
+    const text = JSON.stringify(sqlStmt);
+    expect(text).toMatch(/state\s*=\s*'?created'?/);
+    expect(text).not.toMatch(/state\s*=\s*'?active'?/);
+    expect(text).not.toMatch(/state\s*=\s*'?completed'?/);
+  });
+
+  it("targets only THIS reminder's singletonKey (doesn't cross-cancel other reminders)", async () => {
+    await scheduleReminderFire(fakeBoss, REMINDER_ID, FIRE_AT);
+    const sqlStmt = dbExecuteMock.mock.calls[0]![0];
+    const text = JSON.stringify(sqlStmt);
+    // The reminderId must appear in the WHERE clause's bound params
+    // (drizzle stores them in the serialised payload).
+    expect(text).toContain(REMINDER_ID);
+  });
+
+  it("passes the singleton key through to boss.send for diagnostics", async () => {
+    await scheduleReminderFire(fakeBoss, REMINDER_ID, FIRE_AT);
+    const [, , opts] = bossSendMock.mock.calls[0]!;
+    expect(opts).toMatchObject({
+      singletonKey: SINGLETON_KEY,
+      startAfter: FIRE_AT,
+      retryLimit: 3,
+    });
+  });
+
+  it("still sends when the cancel UPDATE returns zero rows (first-time schedule)", async () => {
+    // First time scheduling a reminder — no stale rows exist.
+    dbExecuteMock.mockResolvedValueOnce({ rows: [] });
+    const result = await scheduleReminderFire(fakeBoss, REMINDER_ID, FIRE_AT);
+    expect(bossSendMock).toHaveBeenCalledTimes(1);
+    expect(result).toBe("new-job-id");
+  });
+
+  it("DEGRADES SAFELY: if the cancel UPDATE throws, the send still runs", async () => {
+    // pg connection blip during cancel must not strand the schedule.
+    // Worst case we end up with two created jobs and the
+    // handler-level recent-run dedupe drops the duplicate fire.
+    dbExecuteMock.mockRejectedValueOnce(new Error("connection reset"));
+    const result = await scheduleReminderFire(fakeBoss, REMINDER_ID, FIRE_AT);
+    expect(bossSendMock).toHaveBeenCalledTimes(1);
+    expect(result).toBe("new-job-id");
+  });
+
+  it("returns boss.send's null when pg-boss itself rejects the send", async () => {
+    // Defense check: if pg-boss returns null for any reason (queue
+    // missing, future stately-style policy quirks, etc), surface that
+    // up so the caller's logger captures jobId: null.
+    bossSendMock.mockResolvedValueOnce(null);
+    const result = await scheduleReminderFire(fakeBoss, REMINDER_ID, FIRE_AT);
+    expect(result).toBeNull();
+  });
+});