Callosium

Overview

Callosium is a Model Context Protocol server that gives you one shared memory across every AI you use, stored in plain Markdown files you own and control. Any MCP-compatible AI assistant can access Callosium's tools directly during conversations and agent runs, deciding when to read from or write to your knowledge base.

It runs locally as an npm package via npx -y callosium, communicating over stdio with no authentication required. Version v0.1.18 is available now under the Apache-2.0 license, with full source code at callosium/callosium on GitHub.

Callosium appears in the Memory category on mcp.site and works with MCP clients including Claude Desktop, Claude Code, Cursor, VS Code, Windsurf, and Zed. If you maintain Callosium, claim this listing to verify ownership and keep information up to date.

Installation

// claude_desktop_config.json
{
  "mcpServers": {
    "callosium": {
      "command": "npx",
      "args": [
        "-y",
        "callosium"
      ]
    }
  }
}