Gemini Gems (https://gemini.google.com/gems/view) are custom agents, and can now be created via a free account.

5 already configured gems are available. The Gems can be used with the 3 available models: Flash 2.0, Flash 2.0 Thinking and Deep research. Once configured, it is possible to add documents and images to the instructions.

Source used for the test: Teaching sheet for the video The fundamentals “Drawing a square” https://lesfondamentaux.reseau-canope.fr/video/mathematiques/geometrie-du-plan/carres/tracer-un-carre