Ask an AI app what Spurgeon preached on Psalm 23 or what Matthew Henry said about Romans 8:28, and it may answer from memory, wording included. Christian Open Library exists to give that app something better to answer from: a free collection of about 4,800 public-domain Christian books and the historic records of more than 80 denominations, which you can search from Claude, ChatGPT or Gemini.^1
You add one address, https://mcp.christianopenlibrary.org/mcp, as a connector in your AI app and sign in with your email address; no GitHub account is needed.^2 The connector's six tools are all read-only: it searches by meaning and by exact words, reads passages and Scripture, finds which historic writers cited a verse, looks up words in older Bible dictionaries, and checks quotations.^3 The corpus holds the Church Fathers, the Reformers, the Puritans, Edwards, historic creeds and confessions, commentaries from Calvin, Matthew Henry, Gill and others, Spurgeon's sermons, the Princeton Review, and the constitutions, disciplines and minutes of more than 80 church bodies up to 1930. You can also scope a question to your own denomination and the bodies it came from, and each answer is labeled with the body, the edition and its year.^1
The library is built for checking. Every passage comes with its source; search results are graded exact, close, partial or loose; when the library has nothing close, the result says NOT FOUND and tells the AI not to quote from memory; and a dedicated tool checks whether an author really wrote the words attributed to him.^3 Quotations from scanned books link straight to the printed page, and passages from scans are marked as uncorrected OCR.^1
The library is the personal project of Matt Miller, a teaching elder in the Presbyterian Church in America at First Presbyterian Church in Louisville, Mississippi. He states plainly that it is not a ministry of his church, his presbytery or the PCA, and that none of them directs or endorses it.^1 Many texts come from the Christian Classics Ethereal Library at Calvin University, the Text Creation Partnership, the Internet Archive, Project Gutenberg and Standard Ebooks.^1
It is free, with no ads and no trackers, and nothing is sold; readers who find it useful can give through GitHub Sponsors, and the gifts go to Miller personally and are not tax-deductible.^1 The connector keeps no copy of your conversations and does not log what you search for.^4
Notable:
- The connector's complete source code is public under the MIT license, published so anyone can see exactly what it does with their questions^3
- A published 75-question test of the search finds the right book in the top 8 results about 87 percent of the time^3
- Scripture reading covers seven public-domain translations, with the Berean Standard Bible by default^3
