diff --git a/paircd/channel.py b/paircd/channel.py
index 5be7818..b99da2d 100644
--- a/paircd/channel.py
+++ b/paircd/channel.py
@@ -1,6 +1,6 @@
 from asyncio import Queue
 from dataclasses import dataclass, field
-from typing import Dict
+from typing import Dict, List
 
 from paircd.client import Client
 from paircd.message import Message
@@ -29,3 +29,6 @@ class Channel:
 
     def write_message(self, msg: Message) -> None:
         self.msg_queue.put_nowait(msg)
+
+    def get_modes(self) -> List[str]:
+        return []
diff --git a/paircd/client.py b/paircd/client.py
index 4df17d9..b7c9550 100644
--- a/paircd/client.py
+++ b/paircd/client.py
@@ -20,7 +20,9 @@ class Client:
     channels: Set[str] = field(default_factory=set)
 
     def id(self) -> str:
-        return f"{self.nickname}!{self.username}@{self.hostname}"
+        nickname = self.nickname or "<unknown>"
+        username = self.username or "<unknown>"
+        return f"{nickname}!{username}@{self.hostname}"
 
     def log(self, msg: str, level: int = INFO) -> None:
         log(level, f"{self.hostname} ({self.id()}) {msg}")
diff --git a/paircd/command_handler.py b/paircd/command_handler.py
index 6fad9f8..7b965be 100644
--- a/paircd/command_handler.py
+++ b/paircd/command_handler.py
@@ -1,4 +1,5 @@
 from abc import abstractmethod, ABC
+from typing import Optional
 
 from paircd.client import Client
 from paircd.message import Message
@@ -7,9 +8,9 @@ from paircd.server import Server
 
 class CommandHandler(ABC):
     cmd: str
-    argc: int
+    argc: Optional[int]
 
-    def __init__(self, cmd: str, argc: int) -> None:
+    def __init__(self, cmd: str, argc: Optional[int] = None) -> None:
         self.cmd = cmd
         self.argc = argc
 
diff --git a/paircd/handler/mode.py b/paircd/handler/mode.py
new file mode 100644
index 0000000..1274c8e
--- /dev/null
+++ b/paircd/handler/mode.py
@@ -0,0 +1,27 @@
+import logging
+from paircd.reply import RPL_CHANNELMODEIS
+
+from paircd.client import Client
+from paircd.command_handler import CommandHandler
+from paircd.message import Message
+from paircd.server import Server
+
+
+class ModeHandler(CommandHandler):
+    def __init__(self) -> None:
+        super().__init__("MODE")
+
+    async def handle(self, server: Server, client: Client, msg: Message) -> None:
+        name = msg.args[0]
+        if not name.startswith("#"):
+            client.log("TODO: implement user mode queries", level=logging.WARN)
+            return
+
+        channel = server.get_channel_by_name(name)
+        modes = "".join(channel.get_modes())
+        if modes != "":
+            modes = f"+{modes}"
+
+        client.log("TODO: implement channel modes", level=logging.WARN)
+        msg = RPL_CHANNELMODEIS(client.nickname, name, modes, "")
+        client.write_message(msg)
diff --git a/paircd/handlers.py b/paircd/handlers.py
index 578e0e5..cc7dfb3 100644
--- a/paircd/handlers.py
+++ b/paircd/handlers.py
@@ -7,6 +7,7 @@ from paircd.message import Message
 from paircd.server import Server
 
 from paircd.handler.join import JoinHandler
+from paircd.handler.mode import ModeHandler
 from paircd.handler.nick import NickHandler
 from paircd.handler.privmsg import PrivmsgHandler
 from paircd.handler.user import UserHandler
@@ -14,6 +15,7 @@ from paircd.handler.who import WhoHandler
 
 HANDLER_CLASSES = [
     JoinHandler,
+    ModeHandler,
     NickHandler,
     PrivmsgHandler,
     UserHandler,
@@ -33,4 +35,13 @@ async def handle_cmd(server: Server, client: Client, msg: Message) -> None:
     if msg.cmd not in CMD_HANDLERS:
         client.log(f"used unknown command {msg.cmd}", level=WARN)
         return
-    await CMD_HANDLERS[msg.cmd].handle(server, client, msg)
+
+    handler = CMD_HANDLERS[msg.cmd]
+    if handler.argc is not None and handler.argc != len(msg.args):
+        client.log(
+            "got {len(msg.args)} arguments for {msg.cmd}, expected {handler.argc}",
+            level=WARN,
+        )
+        return
+
+    await handler.handle(server, client, msg)