diff --git a/tests/setup.js b/tests/setup.js
index 4e4467b..c31a654 100644
--- a/tests/setup.js
+++ b/tests/setup.js
@@ -10,11 +10,25 @@
  * @see docs/ARCHITECT_PLAN.md - Phase 0, Task 0.3
  */
 
-import { beforeAll, afterAll, beforeEach, afterEach } from 'bun:test';
+import { beforeAll, afterAll, beforeEach, afterEach, mock } from 'bun:test';
 import fs from 'fs';
 import os from 'os';
 import path from 'path';
 
+// Mock node-notifier globally
+mock.module('node-notifier', () => {
+  return {
+    default: {
+      notify: (options, callback) => {
+        if (callback) callback(null, 'ok');
+      }
+    },
+    notify: (options, callback) => {
+      if (callback) callback(null, 'ok');
+    }
+  };
+});
+
 // ============================================================
 // TEST ENVIRONMENT CONFIGURATION
 // ============================================================
diff --git a/tests/unit/ai-messages.test.js b/tests/unit/ai-messages.test.js
index 9f7570c..30e2d12 100644
--- a/tests/unit/ai-messages.test.js
+++ b/tests/unit/ai-messages.test.js
@@ -127,7 +127,7 @@ describe('AI Message Generation Module', () => {
         json: () => Promise.resolve({
           choices: [{
             message: {
-              content: 'a'.repeat(201)
+              content: 'a'.repeat(501)
             }
           }]
         })
diff --git a/tests/unit/desktop-notify.test.js b/tests/unit/desktop-notify.test.js
index 1107b39..be8fe99 100644
--- a/tests/unit/desktop-notify.test.js
+++ b/tests/unit/desktop-notify.test.js
@@ -18,29 +18,6 @@ import {
 // Store original os.platform for restoration
 let originalPlatform;
 
-// Mock notifier at module level
-let mockNotify;
-let mockNotifyCallback;
-
-/**
- * Sets up a mock for node-notifier.
- * We need to use dynamic import and module mocking.
- */
-const setupNotifierMock = () => {
-  mockNotifyCallback = null;
-  mockNotify = mock((options, callback) => {
-    mockNotifyCallback = callback;
-    // By default, simulate successful notification
-    if (callback) {
-      callback(null, 'ok');
-    }
-  });
-  
-  return {
-    notify: mockNotify
-  };
-};
-
 describe('desktop-notify module', () => {
   // Import the module fresh for each test
   let desktopNotify;