Check Open Access
checkOpenAccessCheck if a scholarly work is openly accessible and locate a legal version to read. Resolves identifiers like DOI, PMID, or arXiv to determine OA status and gives access URLs.
Instructions
Check whether a single scholarly work is openly accessible and where to find the best legal version. Use when the user asks 'is this open access?', 'where can I read this for free?', or wants the OA license/version before reusing or redistributing. Sourced from Unpaywall. Resolves DOI/PMID/PMCID/arXiv/ISBN/ADS inputs to a DOI before lookup; inputs that don't map to a DOI return doi=null and reason='no_doi'. Single identifier per call — does NOT accept comma/newline batches; loop one call per identifier for multiple papers. Returns: { doi, resolvedFrom?, reason?, result } where result has isOa (boolean), oaStatus ('gold' | 'green' | 'hybrid' | 'bronze' | 'closed'), title, bestLocation ({url, hostType: 'publisher' | 'repository', license, version: 'submittedVersion' | 'acceptedVersion' | 'publishedVersion'} or null), and locations (array of the same shape); result is null when no DOI could be resolved and reason explains why ('no_doi'). No sibling tool overlaps this — resolveIdentifier returns metadata but not OA status. Read-only and idempotent — safe to retry. Works anonymously against the public Scholar Sidekick API (rate-limited free tier); set SCHOLAR_API_KEY (a free ssk_ key from https://scholar-sidekick.com/account) for higher limits, or RAPIDAPI_KEY for paid RapidAPI tiers. Rate limits follow your tier; Unpaywall is queried server-side with its own caching.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| id | Yes | A single scholarly identifier to check. 1–500 characters. Non-DOI inputs are resolved to a DOI server-side before the lookup; if no DOI can be derived, the tool returns doi=null with reason='no_doi'. Pass exactly one identifier — comma/newline batches are NOT accepted by this tool; loop one call per identifier for multiple papers. Accepted: DOI, PMID, PMCID, arXiv ID, ISBN, or NASA ADS bibcode (with or without prefixes). |