Data Driven Custom Commands for Datapacks

As someone who makes datapacks, one thing that has always felt missing is the ability to create proper custom commands that can accept player input.

Right now, if a non-op player needs to provide information to a datapack, the only real option is /trigger, which is limited to integers. If you want players to enter text, such as passwords, town names, dialogue responses, or anything else, you end up having to use awkward workarounds like renaming items in anvils, writing in books, or building large tellraw-based menus.

These solutions work, but they don't feel natural for players and can be difficult to maintain.

I think it would be great if datapacks could register their own commands through a new data/<namespace>/command/ directory. Minecraft already uses Brigadier for command parsing and has function macros, so this seems like a natural extension of the game's increasingly data-driven systems.

For example, a datapack could register a command like /login <password> and automatically pass the entered value to a function macro. The same system could support strings, integers, player names and other existing Brigadier argument types.

This would open up a lot of possibilities for datapack creators all while staying completely vanilla.

Most importantly, it would remove the need for many of the awkward workarounds datapack creators currently rely on and make datapacks feel much more powerful without requiring mods or plugins.