brain — MCP server for your second brain

Give any AI agent a fully searchable, self-organizing knowledge base.

Brain is an MCP (Model Context Protocol) server that connects AI agents to your Obsidian vault. Full-text search, semantic embeddings, voice memo transcription, calendar sync — all exposed as tools your agent can call.

Runs as a sidecar to Hermes Agent or any MCP-compatible client. Powers my second-brain vault with 4,000+ notes.

Why this exists

AI agents have no long-term memory. They forget everything between sessions. Brain gives them persistent, searchable memory — your Obsidian vault becomes their knowledge base. They can read, search, write, and connect ideas across sessions.

Architecture

┌──────────────────────────────────────────┐
│  AI Agent (Hermes / Claude / any MCP)    │
└──────────────┬───────────────────────────┘
               │ MCP (stdio)
┌──────────────▼───────────────────────────┐
│  Brain MCP Server (FastMCP)              │
│                                           │
│  ┌─────────┐ ┌──────────┐ ┌───────────┐  │
│  │  Vault  │ │ Calendar │ │  Whisper   │  │
│  │  Ops    │ │   Ops    │ │  Server    │  │
│  │         │ │          │ │            │  │
│  │ search  │ │ CRUD     │ │ local ≤4m  │  │
│  │ embed   │ │ sync     │ │ Groq >4m   │  │
│  │ ingest  │ │ queue    │ │            │  │
│  │ write   │ │          │ │            │  │
│  └────┬────┘ └────┬─────┘ └─────┬──────┘  │
└───────┼───────────┼─────────────┼─────────┘
        │           │             │
┌───────▼───┐ ┌─────▼──────┐ ┌───▼─────────┐
│ Obsidian  │ │  Google    │ │ Audio Files  │
│ Vault     │ │  Calendar  │ │ (.mp3, .wav) │
└───────────┘ └────────────┘ └──────────────┘

Features

Feature	Tool	Description
Full-text search	search_vault	Regex search across all markdown files
Semantic search	semantic_search	ONNX embeddings, meaning-based retrieval
Audio ingestion	ingest_audio	Voice memo → transcribed → vault (whisper + Groq)
Document ingestion	ingest_document	PDF/text → auto-chunked → vault
Calendar	list_calendar_events	Google Calendar CRUD + sync queue
Dashboard	update_dashboard	Safe task management via dashboard.md
Server health	get_server_status	CPU, RAM, disk, PM2 process health
Telegram bridge	send_telegram_question	Dual-channel ask (CLI + Telegram buttons)

Quick Start

# 1. Clone
git clone https://github.com/jacquesmyo/brain.git
cd brain

# 2. Install
pip install -e .

# 3. Point at your vault
export BRAIN_VAULT_PATH=~/vault

# 4. Start the server
python src/brain/server.py

Then configure your MCP client:

{
  "mcpServers": {
    "brain": {
      "command": "python",
      "args": ["/path/to/brain/src/brain/server.py"]
    }
  }
}

Your agent now has a persistent knowledge base.

Dependencies

• Python 3.12+
• FastMCP — MCP server framework
• ONNX Runtime — embeddings (all-MiniLM-L6-v2, 80MB)
• whisper — local transcription (≤4 min audio)
• Groq API — remote transcription (>4 min audio)
• Google Calendar API — calendar sync

Real-world usage

Brain runs 24/7 on a single Linux box alongside Hermes Agent. It handles:

• 4,000+ markdown notes in the vault
• Hourly calendar sync cron jobs
• Daily physics arxiv paper ingestion
• Voice memo capture → auto-filing
• Automated vault review at 04:00 daily

All CPU-only. No GPU needed.

Related

• second-brain — The vault this server indexes
• moe-tools — AI research framework documented in the vault
• Hermes Agent — Primary MCP client

License

MIT — use it, fork it, ship it. Attribution appreciated.