Application commands are native ways to interact with apps in the Discord client. There are 3 types of commands accessible in different interfaces: the chat input, a message's context menu (top-right menu or right-clicking in a message), and a user's context menu (right-clicking on a user).
CHAT_INPUT
command names and command option names must match the following regex ^[-_\p{L}\p{N}\p{sc=Deva}\p{sc=Thai}]{1,32}$
with the unicode flag set. If there is a lowercase variant of any letters used, you must use those. Characters with no lowercase variants and/or uncased letters are still allowed. USER
and MESSAGE
commands may be mixed case and can include spaces.