diff --git a/beetsplug/bpd/__init__.py b/beetsplug/bpd/__init__.py
index 0d16e22ca..4f04d01fc 100644
--- a/beetsplug/bpd/__init__.py
+++ b/beetsplug/bpd/__init__.py
@@ -674,7 +674,8 @@ class Command(object):
         # Attempt to get correct command function.
         func_name = 'cmd_' + self.name
         if not hasattr(conn.server, func_name):
-            raise BPDError(ERROR_UNKNOWN, u'unknown command', self.name)
+            raise BPDError(ERROR_UNKNOWN,
+                           u'unknown command "{}"'.format(self.name))
         func = getattr(conn.server, func_name)
 
         # Ensure we have permission for this command.
@@ -690,6 +691,13 @@ class Command(object):
                 for data in results:
                     yield conn.send(data)
 
+        except TypeError:
+            # The client provided too many arguments.
+            raise BPDError(ERROR_ARG,
+                           u'wrong number of arguments for "{}"'
+                           .format(self.name),
+                           self.name)
+
         except BPDError as e:
             # An exposed error. Set the command name and then let
             # the Connection handle it.
diff --git a/test/test_player.py b/test/test_player.py
index d7f65ff3f..d2ea496c4 100644
--- a/test/test_player.py
+++ b/test/test_player.py
@@ -347,6 +347,11 @@ class BPDTest(BPDTestHelper):
             response = client.send_command('notacommand')
         self._assert_failed(response, bpd.ERROR_UNKNOWN)
 
+    def test_unexpected_argument(self):
+        with self.run_bpd() as client:
+            response = client.send_command('clearerror', 'extra argument')
+        self._assert_failed(response, bpd.ERROR_ARG)
+
 
 class BPDQueryTest(BPDTestHelper):
     test_implements_query = implements({