sru-mcp

sru-mcp

An MCP server that searches library catalogs worldwide using the SRU (Search/Retrieve via URL) protocol. No API keys required — SRU is an open standard supported by national libraries, university catalogs, and consortia.

Features

• 5 tools for LLM-driven bibliographic search
• 7 pre-configured servers including Library of Congress, BnF, DNB, and more
• Parses MARCXML and Dublin Core record formats
• Supports any SRU-compliant server — pass a URL or use a built-in server ID
• Raw CQL queries or high-level field-based search (title, author, ISBN, subject, etc.)

Quick Start

Install

pip install mcp[cli] httpx xmltodict

Run

python server.py

Claude Desktop

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json):

{
  "mcpServers": {
    "sru": {
      "command": "python",
      "args": ["/path/to/sru-mcp/server.py"]
    }
  }
}

Tools

| Tool | Description | |------|-------------| | sru_list_servers | List all pre-configured library catalog servers | | sru_explain | Get a server's capabilities, supported schemas, and indexes | | sru_list_indexes | List available search indexes on a server | | sru_search | Execute a raw CQL query | | sru_search_books | Search by title, author, ISBN, subject, publisher, year, or keyword |

Example Usage

Search the Library of Congress for books by Melville:

sru_search_books(server="loc", author="Melville", title="Moby Dick")

Search the French national library with a raw CQL query:

sru_search(server="bnf", cql_query='dc.title = "Les Misérables"')

Pre-configured Servers

| ID | Name | Notes | |----|------|-------| | loc | Library of Congress | US national catalog | | loc-names | LC Name Authority | Personal and corporate names | | loc-subjects | LC Subject Authority | Subject headings and genre terms | | bnf | Bibliothèque nationale de France | French national library | | dnb | Deutsche Nationalbibliothek | German national library | | kb | Koninklijke Bibliotheek | Netherlands national library | | bibsys | BIBSYS | Norwegian academic libraries |

To add a server, edit servers.json.

Development

# Install dev dependencies
pip install pytest pytest-asyncio respx

# Run tests
python3 -m pytest test_sru.py test_server.py -v

# Test with MCP Inspector
npx @modelcontextprotocol/inspector python server.py

Project Structure

server.py       FastMCP server — tool definitions
sru.py          SRU protocol client — HTTP, parsing, formatting
servers.json    Server registry
test_sru.py     Tests for sru.py (92 tests total)
test_server.py  Tests for server.py

License

MIT