For Developers & AI
Search, read, and cite rare historical texts via MCP, CLI, or REST. No API key needed.
Request an API Key
For bulk access to OCR text, translations, and page-level data. Keys are reviewed within 24 hours.
What you can build
A researcher studying Renaissance natural philosophy wants to trace how the concept of “spiritus mundi” evolves from Ficino through Agrippa to Fludd. With the MCP server connected to Claude, they search across all three authors' translated works in a single conversation, pull exact passages with page citations, and compile a comparative analysis with DOI-backed references — work that would take days in a physical archive.
The same tools work for building research apps, enriching datasets with primary source references, or giving AI systems grounded access to pre-modern texts that aren't in their training data.
MCP Server
Gives Claude (and any MCP client) direct access to the full collection — search, read, quote, and browse 50,000+ illustrations. One command to install.
claude mcp add source-library -- npx -y @source-library/mcp-server
{
"mcpServers": {
"source-library": {
"command": "npx",
"args": ["-y", "@source-library/mcp-server"]
}
}
}Tools
| search_library | Full-text search across books and page content |
| search_translations | Search inside translated text across the whole library |
| search_within_book | Search inside a specific book's pages |
| list_books | Browse with filters — language, year, category, translation status |
| get_book | Book metadata: summary, chapters, edition info, DOI |
| get_book_text | Read 50+ pages in one call — OCR, translation, or both |
| get_quote | Exact text of a single page with citation URL |
| search_images | Search 50,000+ historical illustrations by subject, symbol, type |
Try asking Claude
“Search for references to ‘prima materia’ across the collection. Which authors discuss it, and how do their treatments differ?”
“Read the full translation of Fludd's History of Both Worlds, pages 1–50. Summarize the cosmological framework.”
“What does Copernicus say about the Sun's centrality in De Revolutionibus? Find the key passages with citation URLs.”
“Find all alchemical emblems depicting the ouroboros. What texts are they from?”
Command Line
Same tools as the MCP server, but standalone with colored terminal output. Add --json for scripts.
# Install npm install -g @source-library/mcp-server # Search the collection source-library search "Paracelsus" --language=German # Search inside translations source-library translations "harmony of the spheres" # Read a book source-library text fludd-utriusque --from=1 --to=50 # Get exact text for quoting source-library quote fludd-utriusque 57 # Browse illustrations source-library images --subject=alchemy --type=emblem # JSON output for piping source-library search "alchemy" --json | jq .results
REST API
Direct HTTP access, no authentication. The MCP server and CLI use these same endpoints.
Base URL: https://sourcelibrary.org/api/searchFull-text search across books and page content
| q | string | Search query (required) |
| language | string | Filter by language |
| year_from / year_to | number | Publication year range |
| sort | string | relevance, date_asc, date_desc, title |
GET /search?q=philosopher's stone&language=Latin/books/:id/textGet full book text (OCR, translation, or both) in a single call
| content | string | ocr, translation, or both (default) |
| from / to | number | Page range (inclusive) |
| format | string | json (structured) or plain (concatenated text) |
GET /books/fludd-utriusque/text?content=translation&from=1&to=50| GET | /books/:id | Book metadata, summary, DOI |
| GET | /books/library | Browse with language/category/collection filters |
| GET | /books/:id/search | Search within a book's pages |
| GET | /books/:id/quote | Single-page text for verbatim quoting |
| GET | /gallery | Search 50,000+ historical illustrations |
| GET | /catalog/csv | Download the full catalog as CSV |
Dataset API
For bulk access to OCR text, translations, and page-level data, request an API key. Keys are reviewed within 24 hours.
Request an API Key
Citation URLs
Every page includes a citation URL linking directly to the source. Published editions have DOIs via Zenodo.
https://sourcelibrary.org/book/fludd-utriusque?page=57
https://sourcelibrary.org/book/fludd-utriusque
Author, Title, trans. Source Library (Year), p. N. DOI: 10.5281/zenodo.xxxxx
/llms.txt
Complete API documentation formatted for LLM consumption.
Pipeline Architecture
How books flow through 10 processing stages: Lambda workers, SQS queues, Gemini AI, backpressure controls. Live counts, diagrams, cost breakdowns.