In the rich text editor:
@gaekey
In a comment:
[gaekey](https://www.chowlings.com/user/gaekey)
For Names and Avatars:
In the rich text editor:
%gaekey
In a comment:
[](https://www.chowlings.com/user/gaekey) [gaekey](https://www.chowlings.com/user/gaekey)