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discord.py 2.0+ slash command info and examples

Slash Commands and you

This short example will cover how to make slash commands within an ext.commands.Bot's extension and Cog ecosystem.

This will cover most slash situations within discord.py

I added how this command would be invoked in the doc strings.

This does not account for the fact you still need to sync Bot.tree somewhere, please remember to do this.

N.B: Ping Umbra#0009 in the d.py server if you want to suggest edits/improvements.

# This an App command group.
# You can nest these down a few levels, like so:-
# /group subcommand (up to 25)
# /group subcommand group
# /group subcommand group subcommand (up to 25).
# this example shows one way to do this, subclassing
# the other is constructing an instance of app_commands.Group()
# that one is shown in "free_function_commands-py"
import discord
from discord import app_commands
# the @app_commands.guilds and @app_commands.default_permissions decorators (also including checks) can be used above the class.
# these will apply to ALL subcommands, subcommands cannot have invidual perms!
@app_commands.guild_only()
class Group(app_commands.Group):
# subcommand of Group
@app_commands.command()
async def my_subcommand(self, interaction: discord.Interaction) -> None:
await interaction.response.send_message("hello from the subcommand!")
# nested group command
group2 = app_commands.Group(name="group2", description="This a nested group!")
# subcommand of group2
@group2.command()
async def my_second_group_command(self, interaction: discord.Interaction) -> None:
await interaction.response.send_message("hello from the second subcommand!")
# unlike commands.GroupCog, you need to add this class to your tree yourself.
tree.add_command(Group())

Syncing the command tree in discord.py

This seems to be a common "gotcha" with users new to the library. As such I have been asked to cover it a bit more here.

CommandTree.sync is how we make Discord aware of our command definitions. This means that we use an API request to send them a copy of what our commands look like and act like, so they can display it to your users in the client. If you do not sync your tree, the commands will not show up, or update them if you make changes locally.

I cover some more items relating to this in the next file below. But for now let's cover the basics and what you can do here.

Common caveats

In my time as Helper, I see people syncing their CommandTree in the on_ready_event or in the new setup_hook entrypoint method. I do not advise this personally, it can lead to footguns if you aren't prepared. For examples, if you sync your tree before you load your extensions (which have your application commands), then you're effectively syncing an empty tree to Discord, which will wipe your commands. If you sync your tree and then make changes, you rely on the autosync and forget to sync changes, resulting in errors and failing commands.

This is why it is strongly recommended to sync on demand with a command (ideally with a message command) and know when to do such things. I cover that later too.

I'll add more things when I can think of them.

Sync examples and details

What I've been recommending to people, is to maintain a sync command as a Message Command (@bot.command()) or some sort of message invoke. Bots without the message content intent will still receive content of messages that mention them or are in DMs.

It's not like you can use a slash command to sync... when that command isn't synced.

Syncing gotchas

There is a ratelimit on syncing global commands which add commands. Updating commands (currently) has no ratelimit.

It is still recommended to sync your commands to a test guild before syncing them globally. Discord.py has added a helper method to do just that: CommandTree.copy_global_to

This util is used as follows:

# you have a defined Bot, with a tree and have commands added to it that are global.

guild = ctx.guild or discord.Object(id=...)  # you can use a full discord.Guild as the method accepts a Snowflake
Bot.tree.copy_global_to(guild=guild)

All this method does is copy your defined global commands (so ones without a guild or guilds kwarg, or without the @app_commands.guilds() decorator) to the specified guild within the CommandTree. When you use this method you must sync afterward still, you can refer to when_to_sync.md for details there.

Sync command example


from typing import Literal, Optional
from discord.ext import commands
from discord.ext.commands import Greedy, Context # or a subclass of yours

@bot.command()
@commands.guild_only()
@commands.is_owner()
async def sync(
  ctx: Context, guilds: Greedy[discord.Object], spec: Optional[Literal["~", "*", "^"]] = None) -> None:
    if not guilds:
        if spec == "~":
            synced = await ctx.bot.tree.sync(guild=ctx.guild)
        elif spec == "*":
            ctx.bot.tree.copy_global_to(guild=ctx.guild)
            synced = await ctx.bot.tree.sync(guild=ctx.guild)
        elif spec == "^":
            ctx.bot.tree.clear_commands(guild=ctx.guild)
            await ctx.bot.tree.sync(guild=ctx.guild)
            synced = []
        else:
            synced = await ctx.bot.tree.sync()

        await ctx.send(
            f"Synced {len(synced)} commands {'globally' if spec is None else 'to the current guild.'}"
        )
        return

    ret = 0
    for guild in guilds:
        try:
            await ctx.bot.tree.sync(guild=guild)
        except discord.HTTPException:
            pass
        else:
            ret += 1

    await ctx.send(f"Synced the tree to {ret}/{len(guilds)}.")

Syncing your commands

At the time of writing this, it's still mostly unclear to most users when they should be syncing their commands to Discord.

Let's try and write up some bullet points:-

When to sync

  • When you add a new command.
  • When you remove a command.
  • When a command's name or description changes.
  • When the callback's parameters change.
    • This includes parameter names, types or descriptions.
    • Also when you add or remove a parameter.
  • If you change a global to a guild command, or vice versa.
    • NOTE: If you do this, you will need to sync both global and to that guild to reflect the change.

These are currently the only times you should re-sync.

import discord
from discord import app_commands
from discord.ext import commands
class MyCog(commands.Cog):
def __init__(self, bot: commands.Bot) -> None:
self.bot = bot
@app_commands.command(name="command-1")
async def my_command(self, interaction: discord.Interaction) -> None:
""" /command-1 """
await interaction.response.send_message("Hello from command 1!", ephemeral=True)
@app_commands.command(name="command-2")
@app_commands.guilds(discord.Object(id=...), ...)
async def my_private_command(self, interaction: discord.Interaction) -> None:
""" /command-2 """
await interaction.response.send_message("Hello from private command!", ephemeral=True)
async def setup(bot: commands.Bot) -> None:
await bot.add_cog(MyCog(bot))
# for simplicity, these commands are all global. You can add `guild=` or `guilds=` to `Bot.add_cog` in `setup` to add them to a guild.
import discord
from discord import app_commands
from discord.ext import commands
class MyCog(commands.GroupCog, name="parent"):
def __init__(self, bot: commands.Bot) -> None:
self.bot = bot
super().__init__() # this is now required in this context.
@app_commands.command(name="sub-1")
async def my_sub_command_1(self, interaction: discord.Interaction) -> None:
""" /parent sub-1 """
await interaction.response.send_message("Hello from sub command 1", ephemeral=True)
@app_commands.command(name="sub-2")
async def my_sub_command_2(self, interaction: discord.Interaction) -> None:
""" /parent sub-2 """
await interaction.response.send_message("Hello from sub command 2", ephemeral=True)
async def setup(bot: commands.Bot) -> None:
await bot.add_cog(MyCog(bot))
# or if you want guild/guilds only...
await bot.add_cog(MyCog(bot), guilds=[discord.Object(id=...)])
import discord
from discord import app_commands
from discord.ext import commands
class MyCog(commands.Cog):
def __init__(self, bot: commands.Bot) -> None:
self.bot = bot
group = app_commands.Group(name="parent", description="...")
# Above, we declare a command Group, in discord terms this is a parent command
# We define it within the class scope (not an instance scope) so we can use it as a decorator.
# This does have namespace caveats but i don't believe they're worth outlining in our needs.
@app_commands.command(name="top-command")
async def my_top_command(self, interaction: discord.Interaction) -> None:
""" /top-command """
await interaction.response.send_message("Hello from top level command!", ephemeral=True)
@group.command(name="sub-command") # we use the declared group to make a command.
async def my_sub_command(self, interaction: discord.Interaction) -> None:
""" /parent sub-command """
await interaction.response.send_message("Hello from the sub command!", ephemeral=True)
async def setup(bot: commands.Bot) -> None:
await bot.add_cog(MyCog(bot))
import asyncio
from discord.ext import commands
from discord import app_commands
# define Bot with **needed** parameters
bot = commands.Bot(command_prefix="some_prefix", intents=some_intents_definition)
# You can now use `@bot.tree.command()` as a decorator:
@bot.tree.command()
async def my_command(interaction: discord.Interaction) -> None:
await interaction.response.send_message("Hello from my command!")
### NOTE: the above is a global command, see the `main()` func below:
# we can even use Groups
group = app_commands.Group(name="some-parent", description="description")
@group.command()
async def my_subcommand(interaction: discord.Interaction) -> None:
await interaction.response.send_message("hello from the subcommand!")
bot.tree.add_command(group, guild=discord.Object(id=...))
async def main():
async with bot:
# do you setup stuff if you need it here, then:
bot.tree.copy_global_to(guild=discord.Object(id=...)) # we copy the global commands we have to a guild, this is optional
await bot.start(MY_TOKEN)
# We still need to sync this tree somehow, but you can make a command as discussed already.
# discord.py recently added full hybrid commands. They work as follows:
## Note: as I don't see a reason not to, I will present an example using a commands.Cog.
## IMPORTANT: hybrid commands only work if the signature is compatible with app commands.
# this means that all parameters must have a type annotation, even if it is just `str`.
# this also means that you must use `Transformers` not `Coverters` in these cases.
import discord
from discord.ext import commands
class MyCog(commands.Cog):
def __init__(self, bot: commands.Bot) -> None:
self.bot: commands.Bot = bot
@commands.hybrid_command(name="ping")
async def ping_command(self, ctx: commands.Context) -> None:
"""
This command is actually used as an app command AND a message command.
This means it is invoked with `?ping` and `/ping` (once synced, of course).
"""
await ctx.send("Hello!")
# we use ctx.send and this will handle both the message command and app command of sending.
# added note: you can check if this command is invoked as an app command by checking the `ctx.interaction` attribute.
@commands.hybrid_group(name="parent")
async def parent_command(self, ctx: commands.Context) -> None:
"""
We even have the use of parents. This will work as usual for ext.commands but will be un-invokable for app commands.
This is a discord limitation as groups are un-invokable.
"""
... # nothing we want to do in here, I guess!
@parent_command.command(name="sub")
async def sub_command(self, ctx: commands.Context, argument: str) -> None:
"""
This subcommand can now be invoked with `?parent sub <arg>` or `/parent sub <arg>` (once synced).
"""
await ctx.send(f"Hello, you sent {argument}!")
async def setup(bot: commands.Bot) -> None:
await bot.add_cog(MyCog(bot))
@AbstractUmbra
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Author

AbstractUmbra commented Oct 6, 2022

Hello Umbra, want to suggest some changes for #file-9-subclassing_group-py...

- # this a app command group
+ # this is an App command group
- # you can nest these up 1: 
- # `/group group` = VALID
+ # Valid combinations:
+ # /group subcommand (up to 25)
+ # /group subcommand group
+ # /group subcommand group subcommand (up to 25)
- # /group group group` = INVALID
- # etc... all invalid.

# this example shows one way to do this, subclassing
# the other is constructing an instance of app_commands.Group()
# that one is shown in "free_function_commands-py"

import discord
from discord import app_commands

- # the @app_commands.guilds and others (including checks) can be used above the class
+ # checks like @app_commands.guilds and @app_commands.default_permissions can be used above the class
- # these will apply to ALL subcommand, subcommands cannot have invidual perms!
+ # these will apply to all subcommands, subcommands cannot have individual perms.
@app_commands.guild_only()
class Group(app_commands.Group):

Done.

@MrDragonBoi
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MrDragonBoi commented Nov 18, 2022

I know this is old, but do you have anything to add an input in the command, like /ban user:<user> reason:[reason] with <> being required and [] is optional?

@DoubleF3lix
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DoubleF3lix commented Nov 28, 2022

I know this is old, but do you have anything to add an input in the command, like /ban user:<user> reason:[reason] with <> being required and [] is optional?

You can give it a default value of something like None and check that in your function accordingly.

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