Four new brains

Open the model picker in XinYu chat and you'll find four new options:

GPT-6 Luna — the lowest-priced GPT. Plenty for everyday questions and prompt tweaks.
GPT-6 Sol — GPT-6's balanced tier, at about a fifth of GPT-6 Astra's price. It keeps reasoning while it uses canvas tools, which makes it a good default for most creative work.
Claude Fable 5.1 — the newer Claude Fable, with flagship-level reasoning and tool use. On hard problems it decides for itself when to think deeper.
DeepSeek V4.1 Flash — DeepSeek's newer lite brain; it thinks before it acts, and lets you watch it think.

Which one to pick

Cheapest: GPT-6 Luna
Want to see how it reasons: DeepSeek V4.1 Flash
Most work: GPT-6 Sol
Hard problems worth paying a little more for: Claude Fable 5.1 or GPT-6 Astra

Every model's price is shown in the picker — glance at it before you switch. You can switch back any time.