diff --git a/qutebrowser/commands/command.py b/qutebrowser/commands/command.py
index 8dd830495..5c5ab1311 100644
--- a/qutebrowser/commands/command.py
+++ b/qutebrowser/commands/command.py
@@ -123,6 +123,7 @@ class Command:
         self.pos_args = []
         self.desc = None
         self.flags_with_args = []
+        self._has_vararg = False
 
         # This is checked by future @cmdutils.argument calls so they fail
         # (as they'd be silently ignored otherwise)
@@ -170,6 +171,8 @@ class Command:
 
     def get_pos_arg_info(self, pos):
         """Get an ArgInfo tuple for the given positional parameter."""
+        if pos >= len(self.pos_args) and self._has_vararg:
+            pos = len(self.pos_args) - 1
         name = self.pos_args[pos][0]
         return self._qute_args.get(name, ArgInfo())
 
@@ -233,6 +236,8 @@ class Command:
             log.commands.vdebug('Adding arg {} of type {} -> {}'.format(
                 param.name, typ, callsig))
             self.parser.add_argument(*args, **kwargs)
+            if param.kind == inspect.Parameter.VAR_POSITIONAL:
+                self._has_vararg = True
         return signature.parameters.values()
 
     def _param_to_argparse_kwargs(self, param, is_bool):
diff --git a/qutebrowser/completion/completer.py b/qutebrowser/completion/completer.py
index 8506f3aa7..4cbdc4724 100644
--- a/qutebrowser/completion/completer.py
+++ b/qutebrowser/completion/completer.py
@@ -49,7 +49,7 @@ class Completer(QObject):
         _last_cursor_pos: The old cursor position so we avoid double completion
                           updates.
         _last_text: The old command text so we avoid double completion updates.
-        _last_completion_func: The completion function used for the last text.
+        _last_before_cursor: The prior value of before_cursor.
     """
 
     def __init__(self, *, cmd, win_id, parent=None):
@@ -62,7 +62,7 @@ class Completer(QObject):
         self._timer.timeout.connect(self._update_completion)
         self._last_cursor_pos = -1
         self._last_text = None
-        self._last_completion_func = None
+        self._last_before_cursor = None
         self._cmd.update_completion.connect(self.schedule_completion_update)
 
     def __repr__(self):
@@ -228,7 +228,7 @@ class Completer(QObject):
             # FIXME complete searches
             # https://github.com/qutebrowser/qutebrowser/issues/32
             completion.set_model(None)
-            self._last_completion_func = None
+            self._last_before_cursor = None
             return
 
         before_cursor, pattern, after_cursor = self._partition()
@@ -242,11 +242,11 @@ class Completer(QObject):
         if func is None:
             log.completion.debug('Clearing completion')
             completion.set_model(None)
-            self._last_completion_func = None
+            self._last_before_cursor = None
             return
 
-        if func != self._last_completion_func:
-            self._last_completion_func = func
+        if before_cursor != self._last_before_cursor:
+            self._last_before_cursor = before_cursor
             args = (x for x in before_cursor[1:] if not x.startswith('-'))
             with debug.log_time(log.completion, 'Starting {} completion'
                                 .format(func.__name__)):
diff --git a/qutebrowser/completion/models/configmodel.py b/qutebrowser/completion/models/configmodel.py
index b462442a0..6ee2f9566 100644
--- a/qutebrowser/completion/models/configmodel.py
+++ b/qutebrowser/completion/models/configmodel.py
@@ -47,12 +47,12 @@ def customized_option(*, info):
     return model
 
 
-def value(optname, *_values, info):
+def value(optname, *values, info):
     """A CompletionModel filled with setting values.
 
     Args:
         optname: The name of the config option this model shows.
-        _values: The values already provided on the command line.
+        values: The values already provided on the command line.
         info: A CompletionInfo instance.
     """
     model = completionmodel.CompletionModel(column_widths=(30, 70, 0))
@@ -64,13 +64,18 @@ def value(optname, *_values, info):
 
     opt = info.config.get_opt(optname)
     default = opt.typ.to_str(opt.default)
-    cur_cat = listcategory.ListCategory(
-        "Current/Default",
-        [(current, "Current value"), (default, "Default value")])
-    model.add_category(cur_cat)
+    cur_def = []
+    if current not in values:
+        cur_def.append((current, "Current value"))
+    if default not in values:
+        cur_def.append((default, "Default value"))
+    if cur_def:
+        cur_cat = listcategory.ListCategory("Current/Default", cur_def)
+        model.add_category(cur_cat)
 
-    vals = opt.typ.complete()
-    if vals is not None:
+    vals = opt.typ.complete() or []
+    vals = [x for x in vals if x[0] not in values]
+    if vals:
         model.add_category(listcategory.ListCategory("Completions", vals))
     return model
 
diff --git a/tests/unit/completion/test_completer.py b/tests/unit/completion/test_completer.py
index 51aa091b9..bdc0c1cf5 100644
--- a/tests/unit/completion/test_completer.py
+++ b/tests/unit/completion/test_completer.py
@@ -129,12 +129,20 @@ def cmdutils_patch(monkeypatch, stubs, miscmodels_patch):
         """docstring."""
         pass
 
+    @cmdutils.argument('option', completion=miscmodels_patch.option)
+    @cmdutils.argument('values', completion=miscmodels_patch.value)
+    def config_cycle(option, *values):
+        """For testing varargs."""
+        pass
+
     cmd_utils = stubs.FakeCmdUtils({
         'set': command.Command(name='set', handler=set_command),
         'help': command.Command(name='help', handler=show_help),
         'open': command.Command(name='open', handler=openurl, maxsplit=0),
         'bind': command.Command(name='bind', handler=bind),
         'tab-detach': command.Command(name='tab-detach', handler=tab_detach),
+        'config-cycle': command.Command(name='config-cycle',
+                                        handler=config_cycle),
     })
     monkeypatch.setattr(completer, 'cmdutils', cmd_utils)
 
@@ -191,6 +199,10 @@ def _set_cmd_prompt(cmd, txt):
     ('/:help|', None, '', []),
     ('::bind|', 'command', ':bind', []),
     (':-w open |', None, '', []),
+    # varargs
+    (':config-cycle option |', 'value', '', ['option']),
+    (':config-cycle option one |', 'value', '', ['option', 'one']),
+    (':config-cycle option one two |', 'value', '', ['option', 'one', 'two']),
 ])
 def test_update_completion(txt, kind, pattern, pos_args, status_command_stub,
                            completer_obj, completion_widget_stub, config_stub,
@@ -211,6 +223,32 @@ def test_update_completion(txt, kind, pattern, pos_args, status_command_stub,
         completion_widget_stub.set_pattern.assert_called_once_with(pattern)
 
 
+@pytest.mark.parametrize('txt1, txt2, regen', [
+    (':config-cycle |', ':config-cycle a|', False),
+    (':config-cycle abc|', ':config-cycle abc |', True),
+    (':config-cycle abc |', ':config-cycle abc d|', False),
+    (':config-cycle abc def|', ':config-cycle abc def |', True),
+    # open has maxsplit=0, so all args just set the pattern, not the model
+    (':open |', ':open a|', False),
+    (':open abc|', ':open abc |', False),
+    (':open abc |', ':open abc d|', False),
+    (':open abc def|', ':open abc def |', False),
+])
+def test_regen_completion(txt1, txt2, regen, status_command_stub,
+                          completer_obj, completion_widget_stub, config_stub,
+                          key_config_stub):
+    """Test that the completion function is only called as needed."""
+    # set the initial state
+    _set_cmd_prompt(status_command_stub, txt1)
+    completer_obj.schedule_completion_update()
+    completion_widget_stub.set_model.reset_mock()
+
+    # "move" the cursor and check if the completion function was called
+    _set_cmd_prompt(status_command_stub, txt2)
+    completer_obj.schedule_completion_update()
+    assert completion_widget_stub.set_model.called == regen
+
+
 @pytest.mark.parametrize('before, newtxt, after', [
     (':|', 'set', ':set|'),
     (':| ', 'set', ':set|'),
diff --git a/tests/unit/completion/test_models.py b/tests/unit/completion/test_models.py
index af0a1ca62..a8c7d9425 100644
--- a/tests/unit/completion/test_models.py
+++ b/tests/unit/completion/test_models.py
@@ -739,6 +739,44 @@ def test_setting_value_completion_invalid(info):
     assert configmodel.value(optname='foobarbaz', info=info) is None
 
 
+@pytest.mark.parametrize('args, expected', [
+    ([], {
+        "Current/Default": [
+            ('true', 'Current value', None),
+            ('true', 'Default value', None),
+        ],
+        "Completions": [
+            ('false', '', None),
+            ('true', '', None),
+        ],
+    }),
+    (['false'], {
+        "Current/Default": [
+            ('true', 'Current value', None),
+            ('true', 'Default value', None),
+        ],
+        "Completions": [
+            ('true', '', None),
+        ],
+    }),
+    (['true'], {
+        "Completions": [
+            ('false', '', None),
+        ],
+    }),
+    (['false', 'true'], {}),
+])
+def test_setting_value_cycle(qtmodeltester, config_stub, configdata_stub,
+                             info, args, expected):
+    opt = 'content.javascript.enabled'
+
+    model = configmodel.value(opt, *args, info=info)
+    model.set_pattern('')
+    qtmodeltester.data_display_may_return_none = True
+    qtmodeltester.check(model)
+    _check_completions(model, expected)
+
+
 def test_bind_completion(qtmodeltester, cmdutils_stub, config_stub,
                          key_config_stub, configdata_stub, info):
     """Test the results of keybinding command completion.