Second MCP Server

Second brain en Obsidian: notas, conceptos como nodos, resurfacing y salud del grafo. En castellano.

Local serverstdio

What is the Second MCP server?

Second MCP server exists for a simple reason — assistants are far more useful when they can act on Second directly instead of describing what you should do. Second brain en Obsidian: notas, conceptos como nodos, resurfacing y salud del grafo. En castellano.

What you get

Tu segundo cerebro, en tu Obsidian, hablando con tu asistente.

What the assistant can call

Once Second is connected, these are the calls the assistant has available:

  • Variable — Qué hace
  • BRAIN_VAULT — La ruta de tu vault (obligatoria; también vale como primer argumento)
  • BRAIN_MODO — Motor de resurgir: lexico o rag
  • BRAIN_RAG_UMBRAL — A partir de cuántas notas puede sugerirse el modo rag

Configuration and credentials

You will need one environment variable: BRAIN_VAULT. Keep credentials in your client's env block or a secrets manager rather than in a file you might commit.

Setting it up

@toportal/second-brain-mcp on npm is all you need. Most clients run it directly, so configuration is a few lines and a restart.

Choosing this one

Plenty of AI and media services servers cover similar ground. The differences that matter in practice are scope of access and how much setup stands between you and a working tool call. Second's toolset — Variable, BRAIN_VAULT, BRAIN_MODO and 1 more — is a fair guide to whether it matches your workflow. It is maintained by Portaltocoding; worth a glance at recent repository activity before you build anything load-bearing on it.

We check each listing at SyncDev against the project's documentation before it goes live — if something here drifts out of date, it is a bug worth reporting.

Before you rely on it

  • It runs with your machine's permissions. That is convenient and also the reason to think about what you point it at before you approve a tool call.
  • MCP clients confirm each tool call by default. Leave that on until you have watched what the second mcp server does with a few real requests.

Available tools

ToolWhat it does
VariableQué hace
BRAIN_VAULTLa ruta de tu vault (obligatoria; también vale como primer argumento)
BRAIN_MODOMotor de resurgir: lexico o rag
BRAIN_RAG_UMBRALA partir de cuántas notas puede sugerirse el modo rag

How to install the Second MCP server

Con cualquier otro cliente MCP:

```json
{
  "mcpServers": {
    "second-brain": {
      "command": "npx",
      "args": ["-y", "@toportal/second-brain-mcp"],
      "env": { "BRAIN_VAULT": "/ruta/a/tu/vault" }
    }
  }
}

Configuration as documented by the project. Restart the client after saving.

Configuration

VariableDescriptionRequired
BRAIN_VAULTConfiguration value read at startup.Optional

Example prompts to try

  • Use Second to Variable.
  • Use Second to BRAIN VAULT.
  • Use Second to BRAIN MODO.

Frequently asked questions

It connects Second to MCP-compatible AI assistants such as Claude and Cursor, exposing 4 tools (Variable, BRAIN_VAULT, BRAIN_MODO, and more) that the assistant can call on your behalf. Instead of copying data back and forth by hand, the assistant works with Second directly.