paper-fetch
自动定位开放获取论文并返回 PDF，节省手工检索时间。
会调用外部 API/网络资源，且可能涉及版权或付费通道。
根据 DOI/标题等优先级检索并获取论文 PDF 的流程说明。
用来帮你找到并下载论文的 PDF，输入 DOI、arXiv id、标题或一堆引用都能处理，优先查开放获取来源再往下检索。常在你需要拿到全文、做文献复现或批量抓论文时用到。特点是按优先级逐步尝试 Unpaywall、Semantic Scholar、arXiv、PMC 等，找不到才当做最后手段才考虑镜像。
▸ 展开 SKILL.md 英文原文
Use whenever the user wants to obtain, download, or fetch a paper's PDF — given a DOI, an arXiv id, a paper title, a citation, or a list of DOIs. Trigger on phrases like "download this paper", "find the PDF for [DOI]", "grab me the [Nature/bioRxiv/arXiv] paper on X", "get the open-access version", "I need this article", or any bulk/batch paper download request, even when the user doesn't explicitly say "PDF" or "DOI". Resolves via Unpaywall → Semantic Scholar → arXiv → PubMed Central → bioRxiv/medRxiv → publisher direct (institutional opt-in) → Sci-Hub mirrors as last-resort fallback.
帮我安装这个 skill：https://raw.githubusercontent.com/Agents365-ai/paper-fetch/main/skills/paper-fetch/SKILL.mdcurl -fsSL "https://raw.githubusercontent.com/Agents365-ai/paper-fetch/main/skills/paper-fetch/SKILL.md"# paper-fetch
Fetch the PDF for a paper given a DOI (or title). Tries multiple sources in priority order and stops at the first hit.
## Resolution order
1. **Unpaywall** — `https://api.unpaywall.org/v2/{doi}?email=$UNPAYWALL_EMAIL`, read `best_oa_location.url_for_pdf` (skipped if `UNPAYWALL_EMAIL` not set)
2. **Semantic Scholar** — `https://api.semanticscholar.org/graph/v1/paper/DOI:{doi}?fields=openAccessPdf,externalIds`
3. **arXiv** — if `externalIds.ArXiv` present, `https://arxiv.org/pdf/{arxiv_id}.pdf`
4. **PubMed Central OA** — if PMCID present, `https://www.ncbi.nlm.nih.gov/pmc/articles/{pmcid}/pdf/`
5. **bioRxiv / medRxiv** — if DOI prefix is `10.1101`, query `https://api.biorxiv.o