Paper Search MCP Server

Instructions

Implementation Reference

• paper_find_mcp/server.py:892-922 (handler)

  MCP tool handler for 'download_scihub'. Decorated with @mcp.tool(), includes type hints, detailed docstring (schema), and delegates execution to SCIHUB.download_pdf.
  @mcp.tool() async def download_scihub(doi: str, save_path: Optional[str] = None) -> str: """Download paper PDF via Sci-Hub using DOI (for older papers only). USE THIS TOOL WHEN: - You have a DOI and need the full PDF - The paper was published BEFORE 2023 - The paper is behind a paywall and not on arXiv - You first searched CrossRef and got the DOI WORKFLOW: search_crossref(query) -> get DOI -> download_scihub(doi) Args: doi: Paper DOI (e.g., '10.1038/nature12373', '10.1126/science.1234567'). save_path: Directory to save PDF (default: ~/paper_downloads). Returns: Path to downloaded PDF file (e.g., 'downloads/scihub_10.1038_xxx.pdf'), or error message if download fails. Example: download_scihub("10.1038/nature12373") # 2013 Nature paper """ if save_path is None: save_path = get_download_path() try: return SCIHUB.download_pdf(doi, save_path) except Exception as e: logger.error(f"Sci-Hub download failed: {e}") return f"Error: {e}"
• paper_find_mcp/academic_platforms/sci_hub.py:142-221 (helper)

  Core helper method implementing the Sci-Hub PDF download logic: gets PDF URL from Sci-Hub page, downloads preferentially with curl (fallback to requests), validates PDF header and size.
  def download_pdf(self, doi: str, save_path: Optional[str] = None) -> str: """通过 DOI 下载论文 PDF 优先使用 curl（更可靠），失败时回退到 requests。 Args: doi: 论文 DOI（如 "10.1038/nature12373"） save_path: 保存目录（默认 ~/paper_downloads） Returns: 下载的文件路径或错误信息 """ if not doi or not doi.strip(): return "Error: DOI is empty" doi = doi.strip() # 如果未指定路径，使用用户主目录下的 paper_downloads output_dir = Path(save_path) if save_path else Path.home() / "paper_downloads" output_dir.mkdir(parents=True, exist_ok=True) try: # 获取 PDF URL（必须用 requests 解析 HTML） pdf_url = self._get_pdf_url(doi) if not pdf_url: return f"Error: Could not find PDF for DOI {doi} on Sci-Hub" # 生成文件路径 clean_doi = re.sub(r'[^\w\-_.]', '_', doi) file_path = output_dir / f"scihub_{clean_doi}.pdf" # 方法1: 优先使用 curl（更可靠） if self._download_with_curl(pdf_url, str(file_path)): return str(file_path) logger.info("curl failed, falling back to requests...") # 方法2: 回退到 requests（带重试） max_retries = 3 for attempt in range(max_retries): try: response = self.session.get( pdf_url, verify=False, timeout=(30, 180), # 连接 30s，读取 180s stream=True ) if response.status_code != 200: logger.warning(f"Download failed with status {response.status_code}") continue # 流式写入 with open(file_path, 'wb') as f: for chunk in response.iter_content(chunk_size=8192): if chunk: f.write(chunk) # 验证是 PDF with open(file_path, 'rb') as f: header = f.read(4) if header != b'%PDF': logger.warning("Downloaded file is not a PDF") os.remove(file_path) continue logger.info(f"PDF downloaded with requests: {file_path}") return str(file_path) except requests.exceptions.Timeout: logger.warning(f"Timeout (attempt {attempt + 1}/{max_retries})") except Exception as e: logger.warning(f"Download error (attempt {attempt + 1}/{max_retries}): {e}") return f"Error: Could not download PDF for DOI {doi}" except Exception as e: logger.error(f"Download failed for {doi}: {e}") return f"Error downloading PDF: {e}"
• paper_find_mcp/server.py:88-88 (helper)

  Global instance of SciHubFetcher used by the download_scihub handler.
  SCIHUB = SciHubFetcher()
• paper_find_mcp/server.py:36-36 (helper)

  Import of SciHubFetcher class used for the tool implementation.
  from .academic_platforms.sci_hub import SciHubFetcher, check_paper_year