diff --git a/tanco/driver.py b/tanco/driver.py
index 86f9ac7..56f0b96 100644
--- a/tanco/driver.py
+++ b/tanco/driver.py
@@ -46,7 +46,12 @@ def do_login(self, _arg):
             return
         sid = db.get_server_id(self.client.url)
         pre = self.client.get_pre_token()
-        webbrowser.open(self.client.url + 'auth/login?pre=' + pre)
+        url = self.client.url + 'auth/login?pre=' + pre
+        # Always print the URL so headless / remote users can open it manually.
+        print('Open this URL to log in:')
+        print(url)
+        if not webbrowser.open(url):
+            print('(No browser available; open the URL above in any browser.)')
         jwt = self.client.get_jwt(pre=pre)
         data = jwtlib.JWT().decode(jwt, do_verify=False)  # TODO: verify
         uid = db.uid_from_tokendata(sid, data['authid'], data['username'])
@@ -267,7 +272,16 @@ def do_check(arg):
     def do_show(self, arg=None):
         """Show a description of the current test."""
         cfg = runner.load_config()
-        state = db.current_state(cfg.attempt)
+        if not cfg.attempt:
+            print('No active attempt.')
+            print('Use `tanco init` to start a new attempt.')
+            return
+        try:
+            state = db.current_state(cfg.attempt)
+        except IndexError:
+            print('No active attempt.')
+            print('Use `tanco init` to start a new attempt.')
+            return
         if state == 'start':
             print('You have not started the challenge yet.')
             print('Use `tanco check` to make sure your program runs.')
@@ -321,7 +335,16 @@ def do_next(self, _arg):
         # TODO:  double check that all tests pass and repo is clean
 
         cfg = runner.load_config()
-        state = db.current_state(cfg.attempt)
+        if not cfg.attempt:
+            print('No active attempt.')
+            print('Use `tanco init` to start a new attempt.')
+            return
+        try:
+            state = db.current_state(cfg.attempt)
+        except IndexError:
+            print('No active attempt.')
+            print('Use `tanco init` to start a new attempt.')
+            return
         if state == 'done':
             print('You have already completed the challenge!')
             return
@@ -359,6 +382,7 @@ def do_next(self, _arg):
         self.do_show()
 
     def do_spawn(self, _arg):
+        """Spawn the target program as a persistent process"""
         self.target = runner.spawn(runner.load_config())
 
     def ensure_target(self):
@@ -366,6 +390,7 @@ def ensure_target(self):
             self.do_spawn('')
 
     def do_send(self, msg, suppress=False):
+        """Send a message to the target program and print its output"""
         self.ensure_target()
         if msg.endswith(self.end_cmd): msg = msg[:-1]
         self.target.stdin.write(msg + f'\n{self.end_cmd}\n')
diff --git a/tests/test_basic.py b/tests/test_basic.py
index 31aefa7..0a03f52 100644
--- a/tests/test_basic.py
+++ b/tests/test_basic.py
@@ -73,3 +73,79 @@ def test_valid_test_names_accepted(self):
         self.assertEqual(len(c.tests), 2)
         self.assertEqual(c.tests[0].name, 'foo.bar-1')
         self.assertEqual(c.tests[1].name, 'baz_2.A')
+
+
+
+class DriverNextTest(unittest.TestCase):
+    """Regression: tanco next/show must not IndexError when no attempt is active."""
+
+    def setUp(self) -> None:
+        TANCO_SDB_PATH.unlink(missing_ok=True)
+        tanco.database.ensure_sdb()
+        with tanco.database.begin() as conn:
+            cur = conn.execute(
+                'insert into servers (url, name, info) values (?, ?, ?)',
+                (TANCO_SERVER, 'fakeserver', 'fake'))
+            sid = cur.lastrowid
+            cur = conn.execute(
+                'insert into users (sid, authid, username) values (?, ?, ?)',
+                (sid, 'fakeauthid', 'fakeuser'))
+            uid = cur.lastrowid
+            conn.execute('insert into tokens (uid, jwt) values (?, ?)', (uid, 'fakejwt'))
+        self._old_cwd = os.getcwd()
+
+    def tearDown(self) -> None:
+        os.chdir(self._old_cwd)
+        TANCO_SDB_PATH.unlink(missing_ok=True)
+
+    def _run_in_empty_project(self, method_name: str) -> str:
+        import io
+        from contextlib import redirect_stdout
+
+        import tanco.driver
+
+        buf = io.StringIO()
+        with tempfile.TemporaryDirectory() as tmp:
+            os.chdir(tmp)
+            d = tanco.driver.TancoDriver()
+            with redirect_stdout(buf):
+                getattr(d, method_name)('')
+            os.chdir(self._old_cwd)
+        return buf.getvalue()
+
+    def test_next_no_active_attempt_prints_friendly_message(self) -> None:
+        out = self._run_in_empty_project('do_next')
+        self.assertIn('No active attempt', out)
+        self.assertIn('tanco init', out)
+
+    def test_show_no_active_attempt_prints_friendly_message(self) -> None:
+        out = self._run_in_empty_project('do_show')
+        self.assertIn('No active attempt', out)
+        self.assertIn('tanco init', out)
+
+    def test_login_prints_oauth_url(self) -> None:
+        import io
+        from contextlib import redirect_stdout
+        from unittest.mock import MagicMock, patch
+
+        import tanco.driver
+
+        d = tanco.driver.TancoDriver()
+        d.client = MagicMock()
+        d.client.whoami.return_value = None
+        d.client.url = 'https://example.test/'
+        d.client.get_pre_token.return_value = 'PRETOKEN'
+        d.client.get_jwt.side_effect = RuntimeError('stop-after-print')
+
+        buf = io.StringIO()
+        with patch('tanco.driver.webbrowser.open', return_value=False) as open_mock, \
+             patch('tanco.driver.db.get_server_id', return_value=1):
+            with redirect_stdout(buf):
+                try:
+                    d.do_login('')
+                except RuntimeError as e:
+                    self.assertEqual(str(e), 'stop-after-print')
+
+        out = buf.getvalue()
+        self.assertIn('https://example.test/auth/login?pre=PRETOKEN', out)
+        open_mock.assert_called_once_with('https://example.test/auth/login?pre=PRETOKEN')