Fourth Brain Demo vs Unyly Vault
Side-by-side comparison of two Model Context Protocol servers. Pick the right one for Claude Desktop, Claude Code, or Cursor.
An MCP server that connects Claude.ai to a Notion-based marketing knowledge base, enabling search and retrieval across specialized domains like enterprise platf
Your personal markdown knowledge base, accessible to Claude.
Bottom line: Unyly Vault
Unyly Vault is part of Unyly — one-click install across every client (Claude, Cursor, ChatGPT), one account and billing, with your tools and data in a single workspace. Fourth Brain Demo is a mature standalone service with a large audience (more installs); pick it if you're already invested in it. Building a stack from scratch inside Unyly — start with Unyly Vault.
Comparison
| Feature | Fourth Brain Demo | Unyly Vault |
|---|---|---|
| Pricing | Free | Free |
| Installs | — | 2 |
| Rating | — | new |
| Verified | — | |
| Hosted | — | Hosted |
| Tools | — | 6 |
| Unyly ecosystem | — | |
| One account & billing | — | |
| Tools & data in one workspace | — | |
| Category | productivity | productivity |
| Author | Rev4nchist | Unyly |
| Repo | Rev4nchist/fourth-brain-demo | FasadSalatov/unyly |
When to pick Fourth Brain Demo
An MCP server that connects Claude.ai to a Notion-based marketing knowledge base, enabling search and retrieval across specialized domains like enterprise platforms and competitive positioning. It provides tools for RAG-style Q\&A and content browsing to assist with drafting RFPs and value propositions.
When to pick Unyly Vault
# Unyly Vault MCP Connect Claude Desktop / Claude Code / Cursor to your **personal Unyly Vault** — a markdown knowledge base that lives in the cloud, synced to your account at [unyly.org/vault](https://unyly.org/vault). Once installed, Claude gets the following tools: - **vault_search** — full-text search across all your notes - **vault_list** — list notes (filter by tag, pinned, favorite, daily) - **vault_get** — fetch a single note (incl. backlinks) - **vault_create** — create a new markdown note - **vault_update** — edit an existing note - **vault_backlinks** — find every note that links to a slug ## Setup (one command) ```bash curl -fsSL https://unyly.org/install | sh -s -- install unyly-vault ``` The CLI: 1. Detects the `unyly-vault` slug → opens browser → you confirm in-page 2. Issues a personal token bound to your account 3. Writes the right config for **every** MCP-aware IDE on your machine — Claude Desktop, Claude Code, Cursor — with the auth header already filled in Already have the CLI? Just `unyly install unyly-vault`. ## Why bother Unlike a local Obsidian vault, your second brain is now **available to every Claude session** — even on a different machine or via the web app. Notes you write in browser-based Vault are instantly visible to Claude. Notes Claude creates via tools land back in your Vault. It's a true two-way "second brain" backed by the marketplace where you also discover new MCPs.
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