{"sources":[{"id":"openalex","name":"OpenAlex","host":"api.openalex.org","role":"core","needs_key":null,"key_optional":false,"configured":true,"status":"live","cache_ttl_seconds":21600,"rate_limit":"100k calls/day, 10 req/s; polite pool via a mailto contact param.","license":"OpenAlex data is CC0 (public domain); commercial use explicitly permitted.","attribution":"OpenAlex (openalex.org), CC0"},{"id":"crossref","name":"Crossref","host":"api.crossref.org","role":"enrich","needs_key":null,"key_optional":false,"configured":true,"status":"live","cache_ttl_seconds":21600,"rate_limit":"Polite pool via a mailto contact param; be reasonable, cache.","license":"Crossref metadata are open facts (not copyrightable); free REST API.","attribution":"Crossref (crossref.org)"},{"id":"arxiv","name":"arXiv","host":"export.arxiv.org","role":"enrich","needs_key":null,"key_optional":false,"configured":true,"status":"live","cache_ttl_seconds":86400,"rate_limit":"Be polite: ~1 request per 3 seconds (enforced by our throttle).","license":"arXiv metadata are CC0; we link to the abstract page, never rehost PDFs.","attribution":"arXiv (arxiv.org)"},{"id":"unpaywall","name":"Unpaywall","host":"api.unpaywall.org","role":"oa","needs_key":null,"key_optional":false,"configured":true,"status":"live","cache_ttl_seconds":43200,"rate_limit":"100k calls/day; REQUIRES an email contact param on every request.","license":"Unpaywall open data; attribution 'Data from Unpaywall' is REQUIRED.","attribution":"Data from Unpaywall (unpaywall.org)"},{"id":"pubmed","name":"PubMed / NCBI E-utilities","host":"eutils.ncbi.nlm.nih.gov","role":"biomed","needs_key":"NCBI_API_KEY","key_optional":true,"configured":true,"status":"live","cache_ttl_seconds":86400,"rate_limit":"3 req/s keyless, 10 req/s with an optional free NCBI_API_KEY; requires tool and email params.","license":"PubMed records are US public domain; metadata + linkouts only.","attribution":"PubMed / NCBI E-utilities (ncbi.nlm.nih.gov)"},{"id":"semanticscholar","name":"Semantic Scholar","host":"api.semanticscholar.org","role":"enrich","needs_key":"X402_S2_API_KEY","key_optional":true,"configured":true,"status":"live","cache_ttl_seconds":43200,"rate_limit":"Shared unauthenticated pool is heavily throttled (429s live); a free API key gives a private quota.","license":"Semantic Scholar Open Research Corpus; free API, metadata only.","attribution":"Semantic Scholar (semanticscholar.org)"}],"id_schemes":["doi","arxiv","pmid","pmcid","openalex","orcid","ror"],"dedup_key":"doi","contact_email":"contact@agentstools.dev","note":"Provenance, licensing and rate-limits of the open scholarly-metadata sources the paid /scholar/* routes fuse. All permit commercial use; we return metadata and links to legally-hosted open-access copies only, never rehosted full-text.","disclaimer":"Scholarly metadata fused from public/open registries (OpenAlex, Crossref, arXiv, Unpaywall, PubMed, Semantic Scholar). Metadata and links to legally-hosted open-access copies only; we never rehost restricted full-text. Counts may lag registry updates."}