# Brain

> The LLM powering a Mind's reasoning — swappable without replacing the Soul.

The Brain is the LLM layer that powers a Mind's thoughts and reasoning. Tasks are auto-routed to the most appropriate model — reasoning, coding, fast response, and so on — with no single-vendor lock-in.

The Brain is separate from the [Soul](/docs/concepts/soul). If the underlying model is swapped or upgraded, the Mind's identity, [Memory](/docs/concepts/memory), [Tenets](/docs/concepts/tenet), and history remain intact. The Soul persists; only the Brain changes.