From my interactions with the community, I think one of the more appreciated features of the Look At Me Sideways (LAMS) LookML linter is the ability to provide concise custom rules.
However, it’s always been a bit of an arcane art, with very limited tooling, and lots of trial and error. And perhaps more error than not.
Today, that changes! I just released LAMS Rule Sandbox, a single-page app that will let you interactively write and test LAMS custom rules:

If you’re using LAMS, or are interested, give this new tool a spin, and let me know what you think!
(If you’re not yet set up with your own rules, you can load a sample project from the “About” section just to kick the tires.)
PS. I’ve also recently released some other features for LAMS, which you can review in the v2.x release notes.