@evan-moon/memex

memex

Local-first second brain with semantic search. Stores notes as Markdown files and indexes them with a local ML model — no cloud, no API keys.

Works as an MCP server for Claude Code and Claude Desktop, and as a standalone CLI.

Features

• Semantic search — multilingual embeddings via paraphrase-multilingual-MiniLM-L12-v2 (Korean + English, runs fully offline)
• Obsidian-compatible — notes saved as .md files in your vault directory
• MCP server — Claude can save and search your second brain mid-conversation, with built-in instructions for proactive search and save behavior
• CLI — add, search, list, show, edit, delete, and index notes from the terminal
• Local DB — SQLite + sqlite-vec stored at ~/.memex/memex.db

Install

npm install -g @evan-moon/memex

On first run the embedding model (~120MB) is downloaded once to ~/.memex/models/.

CLI

# Add notes
memex add                                   # interactive prompt
memex add --title "Note title" --content "..."
memex add --title "Note title" --file ./note.md
memex add --title "Note title" --content "..." --folder "projects/memex"

# Browse
memex list                                  # recent 10 notes
memex list --limit 20
memex show <id>

# Search
memex search "semantic search query"        # multilingual
memex search "지식 관리" --limit 10

# Edit / delete
memex edit <id>
memex delete <id>
memex delete --yes <id>                     # skip confirmation

# Index external directories
memex source add ~/Documents/My\ Notes      # register a directory
memex source list
memex source remove ~/Documents/My\ Notes
memex index                                 # scan vault + all sources
memex index --force                         # re-index everything

# Config
memex config show
memex config set vault-path ~/Documents/Second\ Brain

# MCP
memex mcp install                           # register with Claude Code
memex mcp path                              # print MCP binary path

MCP server

Claude Code

memex mcp install

Or manually:

claude mcp add memex -- node "$(memex mcp path)"

Claude Desktop

Add to ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "memex": {
      "command": "node",
      "args": ["<path from `memex mcp path`>"]
    }
  }
}

Available tools

Tool	Description
save_note	Save a note (title + markdown content + optional folder)
search_notes	Semantic search across all notes
list_notes	List recent notes
get_note	Get full content of a note by ID
update_note	Update title or content of an existing note
delete_note	Delete a note by ID

The MCP server includes built-in instructions that tell Claude to search before answering and save proactively at the end of conversations — no extra CLAUDE.md setup needed.

Configuration

Config is stored at ~/.memex/config.json.

Key	Default	Description
vault_path	~/Documents/Second Brain	Directory where .md files are saved
sources	[]	Additional directories to index (e.g. existing Obsidian vaults)
aliases	{}	Search alias map, e.g. { "js": ["javascript", "자바스크립트"] }

memex config set vault-path ~/my-vault

Architecture

~/.memex/
  config.json       — vault path, sources, and aliases
  memex.db          — SQLite DB (notes + sqlite-vec embeddings)
  models/           — cached embedding model

<vault>/
  *.md              — notes (Obsidian-compatible)

Monorepo packages:

Package	Role
@memex/db	SQLite schema, drizzle queries, sqlite-vec integration
@memex/embed	Local embedder via @huggingface/transformers
@memex/utils	Config, path helpers, shared utilities
@memex/mcp	MCP server (bundled into CLI dist)

Works with Herald

Memex is the memory layer of the Herald ambient voice assistant stack. When connected, Herald can:

• recall past conversations and decisions by voice
• save new insights mid-conversation without typing
• answer "what did I think about X?" with context from your second brain

Herald + Memex + Firma — ambient voice, persistent memory, and financial intelligence in one personal AI stack.

License

MIT