Google Gemini can answer almost any question, but getting a consistently useful response often means typing the same detailed instructions again and again. Gems are designed to solve that problem.
A Gem is a customized version of Gemini built around a particular job. You give it a role and a set of instructions once, then return to it whenever you need the same kind of help. It is essentially a saved super-prompt that behaves like a dedicated AI assistant. It's a lot like a Claude Skill.