diff --git a/src/artist_tracker/tracker.py b/src/artist_tracker/tracker.py
index 3c31a8f..fce5f1c 100644
--- a/src/artist_tracker/tracker.py
+++ b/src/artist_tracker/tracker.py
@@ -978,8 +978,24 @@ def cmd_track(args, tracker: SpotifyReleaseTracker):
         # Check for redirect URI (required for OAuth)
         if not os.getenv('SPOTIPY_REDIRECT_URI'):
              # If running in a headless env without redirect URI, we can't easily do OAuth flow
-             # But let's try anyway, maybe the user has a cached token
-             pass
+             # Check if we have a valid token (or can refresh one)
+             token_valid = False
+             try:
+                 auth_manager = tracker.sp.auth_manager
+                 token_info = auth_manager.get_cached_token()
+                 if auth_manager.validate_token(token_info):
+                     token_valid = True
+             except Exception:
+                 token_valid = False
+
+             if not token_valid:
+                 logger.warning("SPOTIPY_REDIRECT_URI not set and no valid cached session found.")
+                 logger.warning("Authentication will attempt to use default: http://localhost:8888/callback")
+
+                 print("⚠️  Warning: SPOTIPY_REDIRECT_URI is not set and no valid cached session found.", file=sys.stderr)
+                 print("   Authentication will default to 'http://localhost:8888/callback'.", file=sys.stderr)
+                 print("   If your Spotify App is configured differently, please set SPOTIPY_REDIRECT_URI.", file=sys.stderr)
+                 print("   You will need to copy the URL below to a browser to authorize.", file=sys.stderr)
 
         results = tracker.track_liked_songs(args.max_per_artist)
 
diff --git a/tests/test_cli_oauth.py b/tests/test_cli_oauth.py
new file mode 100644
index 0000000..fa566ec
--- /dev/null
+++ b/tests/test_cli_oauth.py
@@ -0,0 +1,92 @@
+#!/usr/bin/env python3
+"""
+Unit tests for CLI OAuth handling.
+"""
+
+import unittest
+from unittest.mock import Mock, patch
+import os
+import sys
+from io import StringIO
+from artist_tracker.tracker import cmd_track
+
+class TestCmdTrackOAuth(unittest.TestCase):
+    def setUp(self):
+        self.tracker = Mock()
+        self.args = Mock()
+        self.args.liked = True
+        self.args.artist = None
+        self.args.playlists = None
+        self.args.max_per_artist = 10
+        self.args.format = 'tsv'
+
+        # Mock auth_manager on tracker.sp
+        self.tracker.sp = Mock()
+        self.auth_manager = Mock()
+        self.tracker.sp.auth_manager = self.auth_manager
+
+        # Mock track_liked_songs to return valid result structure
+        self.tracker.track_liked_songs.return_value = {
+            'releases': [],
+            'total_releases': 0,
+            'artists_processed': 0
+        }
+
+    @patch('artist_tracker.tracker.os.getenv')
+    def test_warnings_on_missing_redirect_uri_and_no_token(self, mock_getenv):
+        # Simulate missing SPOTIPY_REDIRECT_URI
+        def getenv_side_effect(key, default=None):
+            if key == 'SPOTIPY_REDIRECT_URI':
+                return None
+            return default
+        mock_getenv.side_effect = getenv_side_effect
+
+        # Mock auth_manager to return invalid token
+        self.auth_manager.get_cached_token.return_value = None
+        self.auth_manager.validate_token.return_value = None
+
+        # Capture stderr
+        captured_stderr = StringIO()
+        sys.stderr = captured_stderr
+
+        try:
+            cmd_track(self.args, self.tracker)
+        finally:
+            sys.stderr = sys.__stderr__
+
+        output = captured_stderr.getvalue()
+        self.assertIn("Warning: SPOTIPY_REDIRECT_URI is not set", output)
+        self.assertIn("default to 'http://localhost:8888/callback'", output)
+
+        # It should still try to track
+        self.tracker.track_liked_songs.assert_called_once()
+
+    @patch('artist_tracker.tracker.os.getenv')
+    def test_no_warning_if_token_valid(self, mock_getenv):
+        # Simulate missing SPOTIPY_REDIRECT_URI
+        def getenv_side_effect(key, default=None):
+            if key == 'SPOTIPY_REDIRECT_URI':
+                return None
+            return default
+        mock_getenv.side_effect = getenv_side_effect
+
+        # Mock auth_manager to return VALID token
+        self.auth_manager.get_cached_token.return_value = {'access_token': 'valid'}
+        self.auth_manager.validate_token.return_value = {'access_token': 'valid'}
+
+        # Capture stderr
+        captured_stderr = StringIO()
+        sys.stderr = captured_stderr
+
+        try:
+            cmd_track(self.args, self.tracker)
+        finally:
+            sys.stderr = sys.__stderr__
+
+        output = captured_stderr.getvalue()
+        self.assertNotIn("Warning: SPOTIPY_REDIRECT_URI is not set", output)
+
+        self.tracker.track_liked_songs.assert_called_once()
+
+if __name__ == '__main__':
+    unittest.main()