Search academic papers by relevance via OpenAlex. Returns a compact list with DOI, title, authors, year, venue, citation count, OA status, and top concepts. Use year_from/year_to to constrain the publication year.

Fetch full metadata for a single paper by DOI, including the abstract (reconstructed from OpenAlex), authors with ORCID/affiliations, concepts, and references (enriched from CrossRef).

Find a legal Open Access PDF for a DOI via Unpaywall. Returns the OA status, the best OA location (with direct PDF URL if available), and a list of all OA locations (repository vs publisher, version, license).

Download a PDF to the local PDF directory. Use find_oa_pdf first to obtain a URL. The URL is validated for SSRF safety (private/loopback/metadata IPs are refused) and the bytes are verified to start with the %PDF- magic marker. Downloads are capped at PDF_MAX_BYTES (default 100 MB) and written atomically — a failed download never leaves a partial file at the final path.

Convenience workflow: search OpenAlex for query, then for each top result fetch OA status (Unpaywall). Returns a compact overview suitable for quickly assessing a research area. Abstracts are taken from the search response itself — no extra OpenAlex calls.