Paper Finder in Claude
Find papers, get abstracts. The MCP server is https://papers.openkrill.app/mcp. No key. The steps below are only for Claude. A call to get_paper was checked against that server on 2026-10-01.
What this server answers
Find research papers on a topic, search arXiv preprints, and get a paper's abstract and free full-text link from its DOI, PubMed id or arXiv id.
Ask "find recent open-access papers on retrieval-augmented generation evaluation", "search arXiv for speculative decoding papers from this year" or "get the abstract and open-access link for DOI 10.1038/s41586-021-03819-2".
It reads three public indexes: Europe PMC (life sciences and biomedicine, with PubMed and PubMed Central), Crossref (publisher records from all fields) and arXiv (preprints in physics, mathematics, computer science and more). A topic search asks Europe PMC and Crossref together and returns one merged list, each paper with its authors, year, venue, DOI, citation count and the index it came from.
A paper's open-access link is shown only when the index confirms a free full text: a Europe PMC or PubMed Central copy, an arXiv PDF, or a Crossref record that lists a Creative Commons or public-domain license. A missing link means the index does not confirm one, not that none exists.
It does not check whether a paper was retracted and does not verify reference lists: use the Citation Checker plugin for that. It lists papers and abstracts only. It does not read or summarize full texts, and it gives no medical advice.
It stores nothing about you: answers are cached for a few hours and the only lasting record is a daily count of calls per tool.
What it can do
- Searches Europe PMC and Crossref together for papers on a topic, with an optional start year and an open-access filter
- Searches arXiv preprints by topic, with optional category, start year and newest-first order
- Returns authors, year, venue, DOI, citation count and the index each paper came from
- Shows a free full-text link only when the index confirms one, with its license when stated
- Gets one paper's abstract by DOI, PubMed id or arXiv id
- Names the sources and the date they were read in every answer
Tools
search_papers, Search papers. Use this when the user wants papers on a topic, such as "find recent open-access papers on retrieval-augmented generation evaluation" or "systematic reviews on intermittent fasting". Pass topic words, and optionally from_year, open_access_only and a limit of up to 10. Asks Europe PMC and Crossref together and returns one merged list with each paper's authors, year, venue, DOI, citation count, free full-text link when the index confirms one, and the index it came from. Does not search arXiv: use search_arxiv for preprints. Not for retraction or reference checks: use the Citation Checker plugin.search_arxiv, Search arXiv. Use this when the user wants preprints from arXiv, such as "search arXiv for speculative decoding" or "newest cs.CL papers on tokenization". Pass topic words, and optionally an arXiv category such as cs.CL, from_year, sort (relevance or newest) and a limit of up to 10. Returns each preprint's title, authors, year, the start of its abstract, its arXiv page and its PDF link. Preprints are not peer reviewed.get_paper, Get a paper. Use this when the user gives a DOI, PubMed id or arXiv id and wants the paper's abstract or a free full-text link, such as "get the abstract for DOI 10.1038/s41586-021-03819-2". Pass exactly one of doi, pmid or arxiv_id. Returns the title, authors, year, venue, the start of the abstract, the free full-text link and license when the index confirms them, and the index it came from. It does not say whether the paper was retracted or whether a reference is correct: use the Citation Checker plugin for that.
Add Paper Finder in Claude
Claude connects to a remote MCP server as a custom connector. The connection is made from Anthropic's cloud, not from your laptop, so the server must be on the public internet. Paper Finder is. These steps were checked against Claude's custom-connector article (updated 2026-08-11) and the Claude Code MCP docs on 2026-10-01.
On a Pro or Max plan:
- Open Customize, then Connectors.
- Select the plus button, then Add custom connector.
- Paste
https://papers.openkrill.app/mcp. Leave Advanced settings empty: this server does not need an OAuth client id or secret. - Select Add. The connector is yours. Anthropic has not reviewed it, and it is not a Directory listing.
- In a conversation, open the plus button, then Connectors, and enable Paper Finder. Ask: Find recent open-access papers on retrieval-augmented generation evaluation
On Team and Enterprise, an Owner adds the connector first at Organization settings, then Connectors, then Add, then Custom, then Web, and pastes the same URL. Members then connect it from Customize. A Free plan can add one custom connector.
In Claude Code, add it from the project directory:
claude mcp add --transport http papers https://papers.openkrill.app/mcpThat writes a local or user config. A JSON entry needs "type": "http" (or streamable-http) plus the url. An entry with a url and no type is skipped. Confirm with claude mcp get papers. The tools you should see are search_papers, search_arxiv, get_paper.
Enable the connector only in conversations that need it. Claude can call the tools while you work, including during research, so turn off any tool you do not want invoked. Paper Finder does not write to your accounts. It still receives the arguments of each call. Read the privacy page before you paste anything that is not public.
A call checked on 2026-10-01
This DOI is the paper in the plugin's starter prompts. A missing full-text link is not proof that no free copy exists. The request below was posted to https://papers.openkrill.app/mcp as tools/call. HTTP 200. Source: the Paper Finder server, read 2026-10-01.
{
"method": "tools/call",
"params": {
"name": "get_paper",
"arguments": {
"doi": "10.1038/s41586-021-03819-2"
}
}
}- status. ok
- asOf. 2026-10-01
- source. Europe PMC (https://europepmc.org)
- notice. These are records from public indexes, not endorsements. To check whether a paper was retracted or to verify a reference list, use the Citation Checker plugin.
Repeat the call yourself if you need a newer reading. Cached answers expire. A rate limit is not a result: wait and try again. Nothing in the call is a ranking, a filing, or advice.