check-open-access

# checkOpenAccess Resolves an identifier to a DOI, then looks up its open-access status via Unpaywall. Returns the best legal full-text location (preferring publisher copies, then repository copies), the licence, and the version (preprint, accepted, or published). ## When to use - A user asks "is there a free copy?" or "where can I read this without a paywall?" - An agent is preparing a reading list and wants to surface freely-readable links. - A library or syllabus tool wants to filter recommendations by accessibility. ## Inputs - `id` (string, required) — one identifier per call: DOI (including shortDOI aliases like `10/aabbe`), PMID, PMCID, arXiv ID, ISBN, or ADS bibcode. Pass it verbatim. Items with no DOI return a "no DOI" result. ## Outputs ```json { "ok": true, "doi": "10.1371/journal.pone.0173664", "result": { "isOa": true, "oaStatus": "gold" | "green" | "hybrid" | "bronze" | "closed", "title": "...", "bestLocation": { "url": "https://...", "hostType": "publisher" | "repository", "license": "cc-by" | null, "version": "publishedVersion" | "acceptedVersion" | "submittedVersion" | null }, "locations": [{ "url": "https://...", "hostType": "...", "license": null, "version": null }] } } ``` - `resolvedFrom` (`{ type, value }`) is present only when the input was not already a DOI. - When no DOI can be found, `result` is `null` and `reason` is one of `no_doi` / `timeout` / `upstream`. ## Underlying surfaces - **REST**: `POST /api/oa-check` with `{ "id": "…" }`. - **Web UI**: [`/tools/open-access-checker`](https://scholar-sidekick.com/tools/open-access-checker). - **MCP tool**: `checkOpenAccess`. ## Example ```bash curl -sS -X POST "https://scholar-sidekick.com/api/oa-check" \ -H "Content-Type: application/json" \ -d '{"id":"10.1371/journal.pone.0173664"}' ``` ## See also - `resolveIdentifier` for full metadata. - `checkRetraction` for retraction-awareness on the same identifier.