How to use the Calibre E-book Library CLI agent skill

What the skill lets the agent do

The skill wraps the real Calibre tools already on your computer: calibredb, ebook-convert and ebook-meta. Rather than reimplementing them, the CLI calls these tools and returns results in a structured form.

Commands are grouped into Library, Books, Meta, Formats, Custom columns and Catalog. Together they cover connecting to a library, listing and searching books, setting fields such as title, authors, tags, series and rating, converting between formats, exporting books or chapters, and generating a catalog in EPUB, CSV or OPDS.

• Library: connect to a library, show statistics, check integrity
• Books: list, search, add, remove, show, export, export chapters as PDF
• Meta: get, set and embed metadata
• Formats: list, add, remove and convert formats
• Custom: list, add, remove and set custom columns
• Catalog: generate a library catalog

Install the skill

There are two ways to add the skill as a folder of files. Download the ZIP from this page and unzip it into ~/.claude/skills/ for personal use, or into a project's .claude/skills/ folder to limit it to that project. In the Claude apps you can instead upload the ZIP under Settings, then Capabilities, then Skills.

The skill's own instructions also describe installing the CLI itself as a Python package from the CLI-Anything repository. Calibre must already be installed, because the CLI depends on it.

• Python 3.10 or newer is required.
• Calibre must be installed. The source gives sudo apt-get install calibre for Debian/Ubuntu and brew install --cask calibre for macOS.
• Confirm the tools are on your PATH with which calibredb, which ebook-convert and which ebook-meta.

Connect the CLI to your library

Point the CLI at your Calibre library folder once, and it saves the path for later sessions. You can also set the CALIBRE_LIBRARY environment variable, or pass the --library flag on each command. The skill's session state is stored in ~/.cli-anything-calibre/session.json.

Calling the CLI with no subcommand opens an interactive session with tab-completion and history. Type help to list commands and quit or exit to leave.

How to trigger the skill with natural requests

You do not need to type commands yourself. Once the skill is installed, ask the agent for an outcome in plain language, and name Calibre so it knows which tool to use. Mention the book, author, tag or format you care about, and say what should change.

Good requests are specific about the scope. Before any change, ask the agent to list or search first, so you can confirm which books it will touch.

• Find every book by Asimov tagged scifi in my Calibre library and list the titles.
• Set the rating to 5 and series to Foundation for book 42, then show me its metadata.
• Convert book 42 from EPUB to MOBI and tell me where the file is.
• Export each chapter of book 42 as a PDF into ./pdfs, using only chapters 1 to 5.

Search and edit metadata safely

Searches use the Calibre query language. Common patterns include author:, title:, tags:, rating:>3, series:, pubdate: date ranges, identifiers:isbn: and has:cover. You can combine them with and, and negate with not:.

Metadata edits change the book itself. The source lists meta set for single fields, meta embed to write metadata into book files, and books remove, which either moves books to the trash or deletes them permanently. Check the results with show or meta get afterwards.

• Key fields include title, authors, tags, series, series_index, rating (1 to 5), publisher, pubdate, comments, languages and identifiers.
• Use --json when you want the agent to parse output.

Convert formats and export chapters

Conversion uses ebook-convert underneath. Supported inputs in the source include EPUB, MOBI, AZW, AZW3, PDF, HTML, DOCX, ODT, FB2, TXT, RTF and LIT. Supported conversion outputs include EPUB, MOBI, AZW3, PDF, HTML, DOCX and TXT.

Chapter export only works on EPUB files, so convert the book to EPUB first if it is in another format. Each chapter is written as a separate PDF.

Safety, back-ups and tips

The skill runs scripts on your machine and the item's listing says it does not use the network. Metadata edits, removals and format changes modify files directly, so back up your Calibre library before the agent runs anything that writes to it. Run a check with the library check command first to confirm the library is in good shape.

For agent use, the source recommends always using --json, checking return codes (0 means success), parsing stderr on failure, and verifying that output files exist after exports or conversions.

• Back up the library folder before bulk edits or removals.
• Start with read-only commands such as list, search and show.
• Use --json and check return codes when scripting.
• Verify output files exist after export or conversion.
• Calibre must be closed or the library accessed only through these tools if you see conflicts; the source does not cover this, so check Calibre's own guidance.