# sru-mcp

An MCP server that searches library catalogs worldwide using the [SRU (Search/Retrieve via URL)](https://www.loc.gov/standards/sru/) 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

```bash
pip install mcp[cli] httpx xmltodict
```

### Run

```bash
python server.py
```

### Claude Desktop

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

```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

```bash
# 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