Search open catalogs (OpenAlex + arXiv) for academic papers.

Use this first when the user needs papers, citations, or a reading list. Does not download PDFs. Prefer hits with pdf_url for the next step.

Ranking: pass sort=cited_by when the user wants the most cited / famous / popular papers. Pass sort=relevance (default) for topical match. Aliases like "most cited" are accepted; unknown values fall back to relevance.

A doi or arxiv_id looks up that paper (query may be empty). If query itself is a DOI or arXiv id, it is treated as a lookup, not keywords. Identifier filters win over a keyword query.

cited_by ranks on OpenAlex citation counts. arXiv keyword hits are skipped in that mode because they have no citation counts.

Possible error_code values: source_unavailable (one or both catalogs failed; remaining hits may still be useful). Empty papers is still status=ok.

Download an open-access PDF. Does not create Markdown files.

Accepts a DOI or arXiv id. Resolves legal OA copies via OpenAlex locations, Unpaywall (preprints / accepted manuscripts), arXiv/PMC, and a few curated public URLs (e.g. the Bitcoin whitepaper on bitcoin.org). Does not bypass paywalls: publisher HTML is skipped.

Status values: ok, not_found, no_open_pdf, download_failed, invalid_path.

Fetch the official Crossref/DOI BibTeX entry and append it locally.

Skips the write when the DOI or cite key is already in the file (status=duplicate). Failures leave the .bib unchanged.

Status values: added, duplicate, not_found, error, invalid_path.

Return named sections from a local PDF using heading heuristics.

Not a trained parser: headings are matched case-insensitively with aliases (e.g. Methodology ≡ Methods ≡ Materiais and Methods; Abstract ≡ Resumo). Missing sections are listed in unmatched; they do not fail the tool.

Status values: ok, file_not_found, parse_error, invalid_path. Does not fetch URLs — pdf_path must already exist in the workspace.