fix(heartbeat): fallback on invalid notify_cooldown values

docs/plans/state.json

@@ -193,7 +193,7 @@
       "status": "completed",
       "date": "2026-02-16",
       "updated": "2026-02-16",
-      "summary": "Implemented operator-focused hardening and onboarding polish: added setup Operator Pack flows in both Automation menu and first-run wizard to preconfigure scheduled backups, heartbeat alerts, daily briefing, and default MinIO sync; added operator-pack prompts for output channel/peer routing; added heartbeat notification throttling via `automation.heartbeat.notify_cooldown`; and added `flynn doctor --strict` to treat warnings as failures. Updated docs/default config examples and onboarding tests accordingly.",
+      "summary": "Implemented operator-focused hardening and onboarding polish: added setup Operator Pack flows in both Automation menu and first-run wizard to preconfigure scheduled backups, heartbeat alerts, daily briefing, and default MinIO sync; added operator-pack prompts for output channel/peer routing; added heartbeat notification throttling via `automation.heartbeat.notify_cooldown` (with invalid-value fallback handling); and added `flynn doctor --strict` to treat warnings as failures. Updated docs/default config examples and onboarding tests accordingly.",
       "files_modified": [
         "src/cli/setup/config.ts",
         "src/cli/setup/config.test.ts",
@@ -3499,7 +3499,7 @@
     }
   },
   "overall_progress": {
-    "total_test_count": 1869,
+    "total_test_count": 1870,
     "all_tests_passing": true,
     "p0_completion": "3/3 (100%)",
     "p1_completion": "4/4 (100%)",

src/automation/heartbeat.test.ts

@@ -307,6 +307,30 @@ describe('HeartbeatMonitor', () => {
     }));
   });
 
+  it('falls back to default cooldown when notify_cooldown is invalid', async () => {
+    const mockSend = vi.fn().mockResolvedValue(undefined);
+    const mockGet = vi.fn().mockReturnValue({ send: mockSend });
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
+
+    const deps = makeDeps({
+      config: makeConfig({
+        checks: ['model'],
+        failure_threshold: 1,
+        notify_cooldown: 'not-a-duration',
+        notify: { channel: 'telegram', peer: '123' },
+      }),
+      modelRouter: undefined,
+      channelLookup: { get: mockGet },
+    });
+    monitor = new HeartbeatMonitor(deps);
+
+    await monitor.runChecks();
+    expect(mockSend).toHaveBeenCalledTimes(1);
+    expect(warnSpy).toHaveBeenCalledWith(expect.stringContaining('invalid notify_cooldown'));
+
+    warnSpy.mockRestore();
+  });
+
   it('recovery notification sent when checks pass after failures', async () => {
     const mockSend = vi.fn().mockResolvedValue(undefined);
     const mockGet = vi.fn().mockReturnValue({ send: mockSend });

src/automation/heartbeat.ts

@@ -485,8 +485,18 @@ export class HeartbeatMonitor {
     return Date.now() - lastAt >= cooldownMs;
   }
 
+  private getNotifyCooldownMs(): number {
+    const raw = this.deps.config.notify_cooldown ?? '30m';
+    try {
+      return parseInterval(raw);
+    } catch {
+      console.warn(`HeartbeatMonitor: invalid notify_cooldown '${raw}', falling back to 30m`);
+      return parseInterval('30m');
+    }
+  }
+
   private async notifyFailureWithCooldown(text: string, signature: string): Promise<boolean> {
-    const cooldownMs = parseInterval(this.deps.config.notify_cooldown ?? '30m');
+    const cooldownMs = this.getNotifyCooldownMs();
     const signatureChanged = signature !== this.lastFailureSignature;
     const cooldownPassed = this.shouldNotifyByCooldown(this.lastFailureNotificationAt, cooldownMs);
     if (!signatureChanged && !cooldownPassed) {
@@ -500,7 +510,7 @@ export class HeartbeatMonitor {
   }
 
   private async notifyRecoveryWithCooldown(text: string): Promise<boolean> {
-    const cooldownMs = parseInterval(this.deps.config.notify_cooldown ?? '30m');
+    const cooldownMs = this.getNotifyCooldownMs();
     const cooldownPassed = this.shouldNotifyByCooldown(this.lastRecoveryNotificationAt, cooldownMs);
     if (!cooldownPassed) {
       return false;