Errors, checks, and cooldowns

Prefix command exceptions are emitted as command_error; application-command callback exceptions are emitted as application_command_error.

bot:on("command_error", function(message, err)
    print("Prefix command failed:", tostring(err))
    message:reply("Command failed.")
end)

bot:on("application_command_error", function(ctx, err)
    print("Application command failed:", tostring(err))
    ctx:respond("Command failed.", { ephemeral = true })
end)

Do not assume a component callback is protected by the application-command handler: the component dispatcher calls callbacks directly. Handle errors inside such callbacks when necessary.

Checks

Checks are tables with a func(ctx) function. Pass an array as checks to register_command, slash-command options, bridge-command options, groups, or context menus.

local checks = require("discord.lua/lib/commands/checks")

bot:slash_command("owner", {
    description = "Owner-only command",
    checks = { checks.user("123456789012345678") },
    callback = function(ctx)
        ctx:respond("Allowed")
    end,
})

The module also exposes owner, admin, staff, mod, guild, bot, and raw. A false result suppresses the callback. The role-based helpers call ctx.bot:get_member and ctx.bot:get_role, whose current Bot implementations are placeholders; do not rely on these helpers until those lookups are implemented.

Cooldowns

lib/commands/cooldown.lua provides check objects and raises CommandOnCooldown with retry_after when a command is still limited. Attach its returned value in the same checks array and handle the raised error in the relevant command-error event.

The public exception base types are in lib/core/errors.lua. Their concrete messages and fields are documented in Enums, errors, and utilities.