paper-lookup
Search 11 academic literature APIs for papers, preprints, citations, and open-access full text, and return results with reproducible provenance. Covers PubMed, PMC (full text), Europe PMC (full-text and preprint search), bioRxiv, medRxiv, arXiv, OpenAlex, Crossref, Semantic Scholar, CORE, Unpaywall. Use when searching for papers, citations, DOI/PMID/arXiv lookups, abstracts, full text, open-access PDFs, preprints, citation graphs, author publications, or any scholarly literature query. Triggers on mentions of any supported database or requests like "find papers on X", "look up this DOI", "who
npx skills add K-Dense-AI/scientific-agent-skills --skill paper-lookup --agent claude-code
Same command for any agent — swap --agent for codex, cursor, copilot.
Weekly change comes from our own snapshots, not the repository page — it measures attention, not adoption.
# Paper Lookup This skill gives you 11 academic literature APIs with documented endpoints. Your job is to turn the user's intent into a reproducible retrieval: pick the authoritative database(s), make bounded and rate-limited calls, and return an answer with enough provenance (endpoints, parameters, identifiers, access date) that a human or another agent can repeat it. A literature lookup is only as trustworthy as it is repeatable. Prefer explicit identifiers and documented endpoints over broad guessing, report what you queried, and say plainly when a result is partial or a database came back empty — a silent gap reads as "nothing exists" when it may just mean "not indexed here." **These APIs fail with HTTP 200.** That is the recurring hazard across all eleven, and the reason for most of the rules below. PMC eFetch returns a well-formed article with no `<body>` when the publisher forbids redistribution. arXiv returns `totalResults: 1` and one entry titled `Error` for a malformed parameter, and silently rewrites an unknown field prefix to `all:`. Europe PMC puts `errCode` in a 200 body. bioRxiv accepts an out-of-step pagination cursor and returns the wrong 30 records. None of these
- Core Workflow
- Database Selection Guide
- By Use Case
- Cross-Database Queries
- Common Identifier Formats
- API Keys and Access
- Making API Calls
- Request guidelines
- Error recovery
- Completeness and reproducibility
- Bundled Scripts
- Output Format
- Adding New Databases
- Available Databases
curl -s --get "https://www.ebi.ac.uk/europepmc/webservices/rest/search" \ curl -s -H "Accept: application/json" -H "x-api-key: $S2_API_KEY" \ Exhaustive preprint walk, reconciled against the reported total python3 scripts/paginate.py --api europepmc --query 'SRC:"PPR" AND "organoid"' --max-records 200 Full text, with the non-OA trap caught rather than reported as success curl -s "https://eutils.ncbi.nlm.nih.gov/entrez/eutils/efetch.fcgi?db=pmc&id=7029759&retmode=xml" \ arXiv Atom, with the Error entry and the version suffix handled curl -s "https://export.arxiv.org/api/query?id_list=1706.03762" | python3 scripts/arxiv_atom.py - OpenAlex abstracts, without the duplicate-position bug the naive inversion has curl -s "https://api.openalex.org/works/doi:10.7717/peerj.4375" | python3 scripts/openalex_abstract.py -
What does the paper-lookup skill do?
Search 11 academic literature APIs for papers, preprints, citations, and open-access full text, and return results with reproducible provenance. Covers PubMed, PMC (full text), Europe PMC (full-text and preprint search), bioRxiv, medRxiv, arXiv, OpenAlex, Crossref, Semantic Scholar, CORE, Unpaywall. Use when searching for papers, citations, DOI/PMID/arXiv lookups, abstracts, full text, open-access PDFs, preprints, citation graphs, author publications, or any scholarly literature query. Triggers on mentions of any supported database or requests like "find papers on X", "look up this DOI", "who
How do I install it?
Run `npx skills add K-Dense-AI/scientific-agent-skills --skill paper-lookup --agent claude-code` — it drops the skill into your project so the agent can pick it up. Swap the --agent value for codex, cursor or copilot if you use one of those.
Where does this skill come from?
From K-Dense-AI/scientific-agent-skills, a repository with 32,619 stars. We read it straight from the repository tree rather than a submitted listing, so what you see here is what is actually published.
Is a popular skill a good skill?
Not necessarily. Stars measure attention, not adoption — a repository can trend for a week and be abandoned. That is why we show the weekly change from our own snapshots next to the total, instead of a single flattering number.