Calibre Manager MCP

An MCP server to manage and organize a Calibre library from an AI assistant (Claude Desktop, Cursor, etc.).

Unlike other Calibre MCPs —which are read-only— this one is built to write and inject metadata and keep your library spotless: tags, authors, series, covers, duplicates, conversion to AZW3 for Kindle, and more.

All writing goes through the official calibredb command, which is the supported, safe way to modify the library: it never touches metadata.db directly, avoiding corruption and conflicts.

Tools

Related MCP server: calibre-mcp

Requirements

• Calibre installed (includes calibredb, ebook-convert and fetch-ebook-metadata).

• Node.js 18 or newer.

Installation

git clone https://github.com/ericknavarro/calibre-manager-mcp.git
cd calibre-manager-mcp
npm install      # installs dependencies and builds (the "prepare" script)

To rebuild after a change:

npm run build

The compiled server lives at dist/index.js.

Configuration in Claude Desktop

Edit claude_desktop_config.json (on Windows: %APPDATA%\Claude\claude_desktop_config.json) and add:

{
  "mcpServers": {
    "calibre-manager": {
      "command": "node",
      "args": ["C:\\Users\\<your-username>\\repos\\calibre-manager-mcp\\dist\\index.js"],
      "env": {
        "CALIBRE_LIBRARY_PATH": "C:\\Users\\<your-username>\\calibre",
        "CALIBREDB_PATH": "C:\\Program Files\\Calibre2\\calibredb.exe",
        "EBOOK_CONVERT_PATH": "C:\\Program Files\\Calibre2\\ebook-convert.exe",
        "FETCH_EBOOK_METADATA_PATH": "C:\\Program Files\\Calibre2\\fetch-ebook-metadata.exe"
      }
    }
  }
}

Restart Claude Desktop. To check it works, ask it: "Run a health_check on Calibre".

Where is my library?

It's the folder that contains metadata.db (in Calibre: top-right, over the library name → "Switch/create library" shows the path). If you omit it, Calibre's default library is used.

Environment variables

Important note: library locking

While the Calibre app is open using that same library, calibredb cannot open it — for reading or writing — because the app holds a lock (you get an error like "Another calibre program is running"). You have two options:

1. Close Calibre before write operations. (simplest)

2. Start Calibre's Content Server and point CALIBRE_LIBRARY_PATH at its URL (http://localhost:8080#library) with a username/password.

In short: keep Calibre closed while you use this MCP, or run the Content Server (which lets multiple programs share the library safely).

Usage examples

Once configured, you can ask Claude things like:

• "Tag book 5 with Philosophy and Stoicism without removing its tags."

• "Set the series 'Greek Classics' on all books by Plato and Aristotle."

• "Find duplicates in my library."

• "Which books have no cover?"

• "Convert book 12 to AZW3 for my Kindle."

• "Fetch the online metadata for 'The Name of the Rose' by Umberto Eco and apply it to book 8."

License

MIT © Erick Navarro