Mnemosyne OS

For people who work with Claude

Claude is brilliant.
And it forgets everything.

Every conversation starts from zero — Claude Desktop, Claude Code, all of them. Mnemosyne OS runs on your machine and keeps what you've already thought: notes, decisions, sessions, years of writing. One MCP connection later, Claude can ask your memory — and it answers locally, from your vaults.

Download — free How it works

One command, no cloud between you

A real MCP server, published, MIT.

Mnemosyne OS publishes @mnemosyne_os/mcp, an open-source MCP server on npm. Claude Desktop and Claude Code speak MCP natively: plug it in and your assistant gains tools to search your memory by meaning, ask for answers grounded in your chronicles, and — if you allow it — write new memories into them.

Claude Code, one line:

claude mcp add mnemosyne -- npx -y @mnemosyne_os/mcp

Claude Desktop, in claude_desktop_config.json:

{
  "mcpServers": {
    "mnemosyne": {
      "command": "npx",
      "args": ["-y", "@mnemosyne_os/mcp"]
    }
  }
}

Beyond recall

Talk with your memory. Ideas come out.

Recall is the floor, not the point. Through MCP, Claude can hold a real working dialogue with your memory: query it, ask it for grounded syntheses, surface resonances — chronicles from distant domains that answer each other. A note from March, a session from last year, a half-buried decision: put in the same room, they start suggesting things.

That's where it gets interesting for builders: original dev ideas don't come out of a blank prompt — they come out of your own corpus colliding with itself. Claude does the walking; the ground is yours.

Governed, not vacuumed

Claude sees the vaults you grant. Nothing else.

Your memory is organized in vaults — one per domain of your life. Each has a scope and a protection level; a vault marked private stays out of reach, even for a well-meaning agent. Mnemosyne never deletes silently and never blends your domains without you.

And one honest sentence, because sovereignty is a matter of precision: the engine runs locally, but what Claude reads through MCP enters your Claude conversation, wherever that runs. You choose what crosses — that is exactly the point.

What it plugs into

Your memory, as Claude reaches it.

Memory rendered as a navigable map of linked nodes
The memory Claude queries: each node a chronicle, each edge a measured link of meaning — on your disk.

Your assistant stops starting from zero.
And its memory stays in your house.

Download — free Why the relationship