Install from the plugin marketplace:

```bash
codex plugin marketplace add https://github.com/levirge/brain
```

Or add the MCP server directly to `~/.codex/config.toml`:

```toml
[mcp_servers.brain]
url = "https://brain.levirge.com/mcp"
# Token fallback — env var holding your workspace token:
bearer_token_env_var = "BRAIN_TOKEN"
```

OAuth is negotiated on connect; the `BRAIN_TOKEN` env var is only needed for
the bearer-token fallback. Restart Codex after installing, then verify with a
read-only call — `kb_overview` returns your workspace's knowledge summary.

## Sharing a workspace across clients

The same Vault answers to every client you connect. An agent in Codex reads
what an agent in Claude Code captured an hour earlier, and both see what a
person wrote in [Obsidian](/brain/docs/install/obsidian) — the knowledge base is
the shared substrate, not a per-client store.

## Other clients

[Claude Code](/brain/docs/install/claude-code),
[Claude Desktop](/brain/docs/install/claude-desktop),
[Obsidian](/brain/docs/install/obsidian), or
[any MCP client](/brain/docs/install/mcp). No workspace yet?
[Request access](/contact).