harvard-library-catalog

name	harvard-library-catalog
description	Search Harvard Library's 13M+ bibliographic records via LibraryCloud and retrieve MARC/MODS data via PRESTO. Use this skill whenever the user wants to look up books, manuscripts, finding aids, or other items in Harvard's library catalog, verify bibliographic information (title, author, ISBN, publication date), find digital collections, or retrieve detailed catalog records. Also triggers when a user extracts a book title from a document and wants to find its full bibliographic metadata.
version	1.0.0

Harvard Library API Skill

Search and retrieve bibliographic records from Harvard Library's catalog of 13M+ items.

Critical: Things Claude Won't Know Without This Skill

LibraryCloud field-based search uses query parameters, NOT Solr syntax

The Item API uses field names as query parameters — not q=field:value Solr syntax.

CORRECT:   https://api.lib.harvard.edu/v2/items.json?title=hamlet&name=shakespeare
WRONG:     https://api.lib.harvard.edu/v2/items?q=title:hamlet

The q= parameter is for keyword search across all fields. Field-specific search uses dedicated parameters like title=, name=, subject=, identifier=, etc.

JSON requires .json in the URL path

Responses are XML by default. To get JSON, append .json before the query string:

JSON:        https://api.lib.harvard.edu/v2/items.json?title=hamlet
Dublin Core: https://api.lib.harvard.edu/v2/items.dc.json?title=hamlet
Default XML: https://api.lib.harvard.edu/v2/items?title=hamlet

PRESTO is for direct record lookup by HOLLIS ID

PRESTO returns raw MARC, MODS, or Dublin Core for a single record by its HOLLIS number. It complements LibraryCloud when you need the original catalog record:

MARC: https://webservices.lib.harvard.edu/rest/marc/hollis/{HOLLIS_ID}
MODS: https://webservices.lib.harvard.edu/rest/mods/hollis/{HOLLIS_ID}
DC:   https://webservices.lib.harvard.edu/rest/dc/hollis/{HOLLIS_ID}

PRESTO returns XML only and does not support JSON serialization. ISBN/barcode lookups may not work on all records.

User-Agent header is required

LibraryCloud returns 403 without a User-Agent header. Always include one:

curl -H 'User-Agent: MyApp/1.0' 'https://api.lib.harvard.edu/v2/items.json?title=hamlet'

The Python script includes this automatically.

Rate limit: max 1 request/second, 300 per 5 minutes

Exceeding this triggers a 5-minute lockout. The Python script handles this automatically.

Choosing an Access Method

Need	Method
Search by title, author, subject, date	LibraryCloud Item API (field params)
Full-text keyword search	LibraryCloud Item API (q= param)
Look up by ISBN, LCCN, or other identifier	LibraryCloud identifier= or q= keyword
Browse digital collections	LibraryCloud collectionTitle= or Collections API
Get raw MARC record for a known HOLLIS ID	PRESTO /rest/marc/hollis/{id}
Faceted browsing (by language, date, genre)	LibraryCloud facets= parameter

Typical Workflow: Book Title to Full Bibliography

This is the primary use case — an LLM extracts a book title from a document and needs complete bibliographic data:

from scripts.harvard_api import HarvardLibraryAPI
api = HarvardLibraryAPI()

# 1. Search by title (and optionally author)
results = api.search(title="The Great Gatsby", name="Fitzgerald")

# 2. Get the first match's summary
if results:
    summary = api.summarize(results[0])
    # → title, author, publisher, date, ISBN, subjects, language, physical description

# 3. For deeper data, get MARC via PRESTO
hollis_id = api.get_record_id(results[0])
if hollis_id:
    marc = api.get_presto_record(hollis_id, format="mods")

Key Search Fields

Field	What it searches	Exact match?
q	All fields (keyword)	No
title	Title, subtitle, part name/number	Yes (title_exact)
name	All name fields (author, editor, etc.)	No
subject	All subject fields (topic, geographic, temporal)	Yes (subject_exact)
identifier	ISBN, LCCN, other system IDs	Yes
languageCode	ISO language code (e.g., chi, eng)	Yes
dateIssued	Publication date (YYYY)	Yes
dates.start / dates.end	Date range filter	—
genre	Genre/form (e.g., "Drawings", "Maps")	Yes (genre_exact)
repository	Harvard library name	Yes
isOnline	Has digital version (true/false)	—
recordIdentifier	HOLLIS/Alma record ID	Yes

Combine fields freely: ?title=hamlet&name=shakespeare&languageCode=ger&dates.start=1900

Pagination

• limit=N (default 10, max 250)
• start=N for offset-based pagination (up to ~30K results)
• cursor=* then cursor={nextCursor} for large result sets (up to 100K)

Facets

Add facets=field1,field2 to get value counts. Useful fields: name, subject, languageCode, genre, resourceType, repository, dateIssued.

?title=china&facets=languageCode,genre

Python Script

Use scripts/harvard_api.py for programmatic access (zero dependencies):

from scripts.harvard_api import HarvardLibraryAPI
api = HarvardLibraryAPI()

# Keyword search
results = api.search(q="Chinese porcelain Ming dynasty")

# Field search
results = api.search(title="dream of the red chamber", languageCode="chi")

# With facets
results, facets = api.search_with_facets(subject="astronomy", facets=["genre", "dateIssued"])

# Pagination
all_results = api.search_all(title="peanuts", name="schulz", max_results=500)

# PRESTO lookup
marc_xml = api.get_presto_record("011557057", format="marc")

# Summarize a record
for r in results[:5]:
    print(api.summarize(r))

API Endpoints

Endpoint	URL
LibraryCloud Items	https://api.lib.harvard.edu/v2/items
LibraryCloud Collections	https://api.lib.harvard.edu/v2/collections
PRESTO (MARC/MODS/DC)	https://webservices.lib.harvard.edu/rest/{format}/hollis/{id}

Related Skills

• wikidata-search: Cross-reference Harvard catalog entries with Wikidata for external identifiers (VIAF, LoC, etc.)
• cbdb-api: Look up authors of Chinese historical texts in CBDB for biographical context

Resources

• references/api_reference.md — Complete field reference with all searchable fields, facets, and query examples
• scripts/harvard_api.py — Full-featured Python client with rate limiting, pagination, and record summarization