Open Library

MCP Open Library

A Model Context Protocol (MCP) server for the Open Library API that enables AI assistants to search for book and author information.

Overview

This project implements an MCP server that provides tools for AI assistants to interact with the Open Library. It allows searching the catalogue by title, author, subject and other fields, searching for authors by name, retrieving detailed author information using their Open Library key, and getting URLs for book covers and author photos. The server returns JSON projections of the Open Library responses rather than the raw payloads.

Features

• Book Search: Search across titles, authors, subjects, places, people, publishers and ISBNs, with sorting and paging (search_books).
• Book Search by Title: Search for books using their title (get_book_by_title).
• Author Search by Name: Search for authors using their name, with paging (get_authors_by_name).
• Get Author Details: Retrieve detailed information for a specific author using their Open Library key (get_author_info).
• Get Author Photo: Get the URL for an author's photo using their Open Library ID (OLID) (get_author_photo).
• Get Book Cover: Get the URL for a book's cover image using various identifiers (ISBN, OCLC, LCCN, OLID, ID) (get_book_cover).
• Get Book by ID: Retrieve detailed book information using various identifiers (ISBN, LCCN, OCLC, OLID) (get_book_by_id).

Search results are paged — every search tool returns at most limit results (default 10, maximum 50) alongside num_found, the total number of matches, which you page through with offset (maximum 1000). The two cover tools check that an image actually exists and say so when it does not, rather than handing back a URL that resolves to a blank placeholder.

Every tool is a read-only lookup and advertises itself as such with the readOnlyHint and openWorldHint annotations, which may allow a client to skip the confirmation prompt it shows for tools that could change something. These are hints: the MCP specification has clients treat annotations as untrusted unless the server is trusted, so the confirmation policy is the client's to decide. Failures — an unreachable API, a rejected argument — come back as a tool result flagged isError, so an assistant can read what went wrong and correct its next call rather than the request failing outright.

Installation

Quick Start

Nothing to install or build. Point an MCP client at the package with npx and it will be fetched on first run:

{

"mcpServers": { "mcp-open-library": { "command": "npx", "args": ["-y", "mcp-open-library"] } } }

In Claude Desktop that goes in claude_desktop_config.json; other clients use the same shape. Restart the client and the seven tools below become available.

MCP Registry

This server publishes to the official MCP Registry as io.github.8enSmith/mcp-open-library from v1.0.3 onwards. Clients that support the registry can install it by that name.

To inspect the published listing:

curl "https://registry.modelcontextprotocol.io/v0.1/servers?search=io.github.8enSmith/mcp-open-library"

Manual Installation

# Clone the repository

git clone https://github.com/8enSmith/mcp-open-library.git cd mcp-open-library

Install dependencies

npm install

Build the project

npm run build

Usage

Running the Server

1. Ensure you are running node v22.23.4 (it'll probably work on a newer version of node but this is what Im using for this test). If you have nvm installed run nvm use.
2. In the mcp-open-library root directory run npm run build
3. Next run npm run inspector. Once built, click the URL with the MCP_PROXY_AUTH_TOKEN query string parameter to open the Inspector.
4. In the Inspector, choose 'STDIO' transport
5. Make sure the command is set to 'build/index.js'
6. Click the 'Connect' button in the Inspector - you'll now connect to the server
7. Click 'Tools' in the top right menu bar
8. Try running a tool e.g. click get_book_by_title
9. Search for a book e.g. In the title box enter 'The Hobbit' and then click 'Run Tool'. Server will then return book details.

Using with an MCP Client

This server implements the Model Context Protocol, which means it can be used by any MCP-compatible AI assistant or client e.g. Claude Desktop. The server exposes the following tools:

• search_books: Search the catalogue by any combination of query, title, author, subject, place, person, publisher and ISBN
• get_book_by_title: Search for book information by title
• get_authors_by_name: Search for author information by name
• get_author_info: Get detailed information for a specific author using their Open Library Author Key
• get_author_photo: Get the URL for an author's photo using their Open Library Author ID (OLID)
• get_book_cover: Get the URL for a book's cover image using a specific identifier (ISBN, OCLC, LCCN, OLID, or ID)
• get_book_by_id: Get detailed book information using a specific identifier (ISBN, LCCN, OCLC, or OLID)

Example `search_books` input:

{

"author": "Ursula K. Le Guin", "subject": "fantasy", "sort": "old", "limit": 2 }

Example `search_books` output:

{

"num_found": 51, "offset": 0, "limit": 2, "results": [ { "title": "A Wizard of Earthsea", "authors": ["Ursula K. Le Guin"], "first_publish_year": 1968, "open_library_work_key": "/works/OL59798W", "edition_count": 87, "author_keys": ["OL31353A"], "best_edition": { "edition_key": "OL5613890M" }, "cover_url": "https://covers.openlibrary.org/b/id/13617691-M.jpg", "ratings_average": 3.95, "ebook_access": "borrowable" } ] }

best_edition is one specific edition of the work — the one Open Library ranks best for your query — carrying that edition's own identifiers. Search results otherwise identify a work (open_library_work_key), which no tool accepts, so this is the route from a search hit to a concrete book.

Its edition_key is an OLID you can pass straight to get_book_by_id for the full edition record, including its complete ISBN arrays:

{ "idType": "olid", "idValue": "OL5613890M" }

The isbn_13 / isbn_10 fields are omitted where Open Library holds no ISBN for that edition — as in the example above, and roughly a third of results — while edition_key is essentially always present. Where an edition lists several ISBNs of one kind, the first is reported; get_book_by_id returns them all.

The search_books tool accepts the following parameters:

• At least one of q, title, author, subject, place, person, publisher or isbn — the request is rejected without one, since an unfiltered search matches the entire catalogue. q takes a free-form Solr query such as subject:cyberpunk AND first_publish_year:[1980 TO 1990]
• language: Optional 3-letter MARC language code (e.g. eng, fre)
• sort: Optional ordering — new, old, random, key, rating, readinglog, want_to_read, currently_reading, already_read or title. Omit for relevance
• limit: Optional, 1–50, defaults to 10
• offset: Optional, 0–1000, defaults to 0

Example `get_book_by_title` input:

{

"title": "The Hobbit", "limit": 1 }

Example `get_book_by_title` output:

{

"num_found": 224, "offset": 0, "limit": 1, "results": [ { "title": "The Hobbit", "authors": ["J.R.R. Tolkien"], "first_publish_year": 1937, "open_library_work_key": "/works/OL27482W", "edition_count": 481, "author_keys": ["OL26320A"], "best_edition": { "edition_key": "OL51709286M", "isbn_13": "9780395520215", "isbn_10": "0395520215" }, "cover_url": "https://covers.openlibrary.org/b/id/14627509-M.jpg", "ratings_average": 4.29, "ebook_access": "borrowable" } ] }

Example `get_authors_by_name` input:

{

"name": "J. R. R. Tolkien", "limit": 2 }

Example `get_authors_by_name` output:

Each result's key can be passed to get_author_info for that author's full record. alternate_names is abridged here.

{

"num_found": 2, "offset": 0, "limit": 2, "results": [ { "key": "OL26320A", "name": "J.R.R. Tolkien", "alternate_names": ["John Ronald Reuel Tolkien", "Tolkien"], "birth_date": "3 January 1892", "top_work": "The Hobbit", "work_count": 355 }, { "key": "OL332676A", "name": "J. R. R. Tolkien Centenary Conference (1992 Keble College, Oxford)", "top_work": "Proceedings of the J.R.R. Tolkien Centenary Conference, 1992", "work_count": 2 } ] }

Example `get_author_info` input:

{

"author_key": "OL26320A" }

Example `get_author_info` output:

{

"name": "J. R. R. Tolkien", "personal_name": "John Ronald Reuel Tolkien", "birth_date": "3 January 1892", "death_date": "2 September 1973", "bio": "John Ronald Reuel Tolkien (1892-1973) was a major scholar of the English language, specializing in Old and Middle English. He served as the Rawlinson and Bosworth Professor of Anglo-Saxon and later the Merton Professor of English Language and Literature at Oxford University.", "alternate_names": ["John Ronald Reuel Tolkien"], "photos": [6791763], "key": "/authors/OL26320A", "remote_ids": { "viaf": "95218067", "wikidata": "Q892" }, "revision": 43, "last_modified": { "type": "/type/datetime", "value": "2023-02-12T05:50:22.881" } }

Example `get_author_photo` input:

{

"olid": "OL26320A" }

Example `get_author_photo` output:

https://covers.openlibrary.org/a/olid/OL26320A-L.jpg

When Open Library has no photo for that author, the tool says so instead of returning a URL:

No author photo available for OLID OL99999999A.

Example `get_book_cover` input:

{

"key": "ISBN", "value": "9780547928227", "size": "L" }

Example `get_book_cover` output:

https://covers.openlibrary.org/b/isbn/9780547928227-L.jpg

As with author photos, a book with no cover produces a message rather than a URL:

No cover image available for OLID OL00000000M.

The get_book_cover tool accepts the following parameters:

• key: The type of identifier (one of: ISBN, OCLC, LCCN, OLID, or ID)
• value: The value of the identifier
• size: Optional cover size (S for small, M for medium, L for large, defaults to L)

Example `get_book_by_id` input:

{

"idType": "isbn", "idValue": "9780547928227" }

**Example `get_book_