search_lcsh
Retrieve official Library of Congress Subject Headings (LCSH) and related terms by querying the public suggest2 API, enabling precise subject-based searches in AI workflows.
Instructions
Search Library of Congress Subject Headings (LCSH) using the public suggest2 API. Returns a dictionary with the top results.
Input Schema
TableJSON Schema
| Name | Required | Description | Default |
|---|---|---|---|
| query | Yes |
Implementation Reference
- src/cataloger_mcp_server/server.py:7-54 (handler)The main handler function for the 'search_lcsh' tool, decorated with @mcp.tool() for registration in FastMCP. It queries the Library of Congress LCSH suggest2 API, parses the response (handling both new 'hits' format and old list format), and returns results as a list of label/uri dicts or error info.
@ mcp.tool() def search_lcsh(query: str) -> dict: """ Search Library of Congress Subject Headings (LCSH) using the public suggest2 API. Returns a dictionary with the top results. """ # Construct the API endpoint for LCSH subject headings url = "https://id.loc.gov/authorities/subjects/suggest2" params = {"q": query, "count": 25} headers = {"User-Agent": "cataloger mcp server/1.0 (contact: your-email@example.com)"} try: response = requests.get(url, params=params, headers=headers, timeout=10) response.raise_for_status() # Try to parse JSON, but handle unexpected formats robustly try: data = response.json() except Exception as json_err: return { "error": f"Failed to parse JSON: {json_err}", "raw_response": response.text, "type": type(json_err).__name__, "traceback": traceback.format_exc() } # Handle new API response format (dict with 'hits') if isinstance(data, dict) and 'hits' in data: results = [] for hit in data['hits']: label = hit.get('aLabel') or hit.get('label') or '' uri = hit.get('uri') or '' results.append({"label": label, "uri": uri}) return {"results": results} # Old format (list with ids/labels) if isinstance(data, list) and len(data) >= 3: results = [] for uri, label in zip(data[1], data[2]): results.append({"label": label, "uri": uri}) return {"results": results} else: return { "error": "Unexpected API response format", "data": data } except Exception as e: return { "error": str(e), "type": type(e).__name__, "traceback": traceback.format_exc() }