Bukkit

How can I make the command gray and not red? Because when I create a command on 1.16 it stays as red which suggests me it is an invalid command. How can I make it red?

you can add an error message with it like error-message: But if it shows an error message even thou you didn't create any command yet, you can check on your Essentials Plugin or any related plugin to change the unknown command error. You can check it on Essentials plugin

 What, how ?

My command works but it looks red when I type it, how can I make it gray because right now it suggests that it is an invalid command by showing it as red.

register: true

just check in the documentation, it's also the first and only answer in the FAQs