## How is Brain different from a vector database or a RAG pipeline?

A vector database is a retrieval primitive: you build and operate the
pipeline around it — chunking, embedding, prompts, permissions, and every
client integration. Brain is the finished system on top: knowledge is
grouped by entity and distilled into compact summaries that cite their
source documents and rebuild when a source changes. Agents don't get raw
chunks back — they get curated, cited knowledge sized for a context window.
And it isn't only retrieval: the same server carries versioned skills and
agent-to-agent handoffs, over the one protocol every client already speaks.

## How is it different from a model vendor's built-in memory?

Vendor memory lives inside one product and stays there. Brain is one memory
shared across Claude, Codex, Obsidian and any MCP client — switch models or
providers and the memory comes with you. Knowledge exports out; nothing is
trapped in a vendor's memory feature.

## Which clients are supported?

Claude Code and Codex install from the GitHub marketplace
(`levirge/brain`); Claude Desktop installs from Settings → Plugins
([step-by-step](/brain/install/claude-desktop)); Obsidian gets search,
publish and two-way sync via the
[levirge/brain-obsidian](https://github.com/levirge/brain-obsidian) plugin;
and any other MCP client connects to `https://brain.levirge.com/mcp` over
Streamable HTTP ([definition](/brain/mcp.json)). Humans use the web UI.

## How do agents authenticate?

OAuth, negotiated when the client connects. Per-user bearer tokens are the
fallback — you issue and revoke them yourself, and Brain stores only the
token's hash, never the raw credential.

## Where does my knowledge go?

Your workspace is tenant-isolated, whichever model lane is active. In
private mode, every model call — categorisation, summarisation, chat — runs
on LLMs Levirge hosts on its own infrastructure; no cloud model provider is
in the path. Hosted mode uses cloud LLMs when speed matters more than
locality. Embeddings and reranking run on Levirge infrastructure in both
modes.

## Can I self-host it?

Not today — we host it. Self-hosting is a roadmap conversation for
enterprise; if Brain needs to run somewhere specific,
[talk to us](/contact).

## What does it cost?

Brain is in early access. Pricing is quoted per workspace and set up on the
access call — [request access](/contact).

## What happens if the same thing is captured twice?

Identical content deduplicates on a content hash, so re-running an ingest
or retrying a failed capture is safe.

## What happens when a source document changes?

The summaries built from it rebuild, and their citations stay pointed at
the documents each statement came from — the distillation doesn't drift
from the source.

## What if an agent is offline when a handoff arrives?

Nothing is lost: handoffs that arrive while a watcher is down are delivered
on its next watch. The inbox watcher wakes a connected agent the moment a
handoff lands, with the sender's context attached.

## What is a Vault?

The unit of partitioning: knowledge belongs to a Vault, Vaults belong to
your Tenant, and access is per-Vault (viewer or member) plus tenant-wide
admin. Personal Vaults are private to their owner and fail closed.