diff --git a/README.md b/README.md
index 31c5266..22d5127 100644
--- a/README.md
+++ b/README.md
@@ -16,5 +16,6 @@ using [HTTP API](https://gitea.brno.mraveniste.cc/turbotraktor/ladylilia.com/src
 
 ### Mod-only commands
 * `!syncquotes` - performs synchronization of the quotes database with Twitch VODs
-* `!command set COMMAND TEXT` - adds a new extra command or updates an existing one
+* `!command set COMMAND TEXT` - adds a new extra command or updates an existing one  
+    - instances of `{user}` in `TEXT` will be substituted when the command is executed
 * `!command unset COMMAND` - removes an existing extra command
diff --git a/clients/discord.py b/clients/discord.py
index c09bbb5..ab4e07c 100644
--- a/clients/discord.py
+++ b/clients/discord.py
@@ -60,7 +60,7 @@ class DiscordClient(discord.Client):
                 await action(server, message.author.id, message, **m.groupdict())
         for cmd, resp in self.extra_commands.items():
             if cmd == message.content:
-                await self.send_message(message.channel, resp)
+                await self.send_message(message.channel, resp.format(user=message.author.mention))
 
     async def _cooldown_failure(self, server, user, message, **kwargs):
         await self.send_message(message.channel,
diff --git a/clients/twitch.py b/clients/twitch.py
index 49b4bd5..31b2d91 100644
--- a/clients/twitch.py
+++ b/clients/twitch.py
@@ -106,7 +106,7 @@ class TwitchClient(irc.bot.SingleServerIRCBot):
                 action(tags, send_response, **m.groupdict())
         for cmd, resp in self.extra_commands.items():
             if cmd == message:
-                send_response(resp)
+                send_response(resp.format(user=tags['display-name']))
 
     def _add_quote(self, tags, send_response, user, id, text, game, date, **kwargs):
         if text[0] == text[-1] == '"':