Paper Search MCP Server

Instructions

Args:
    paper_id: arXiv ID (e.g., '2106.12345', '2312.00001v2').
    save_path: Directory to save PDF (default: ~/paper_downloads).

Returns:
    Path to downloaded PDF file.

Example:
    download_arxiv("2106.12345")

Implementation Reference

• paper_find_mcp/server.py:194-208 (handler)

  MCP tool handler and registration for 'download_arxiv'. This is the entry point decorated with @mcp.tool(), defining input schema via args/docstring and delegating to the generic _download helper using the 'arxiv' searcher.

  @mcp.tool()
  async def download_arxiv(paper_id: str, save_path: Optional[str] = None) -> str:
      """Download PDF from arXiv (always free and available).
      
      Args:
          paper_id: arXiv ID (e.g., '2106.12345', '2312.00001v2').
          save_path: Directory to save PDF (default: ~/paper_downloads).
      
      Returns:
          Path to downloaded PDF file.
      
      Example:
          download_arxiv("2106.12345")
      """
      return await _download('arxiv', paper_id, save_path)

• paper_find_mcp/server.py:115-135 (helper)

  Generic download helper function used by all platform-specific download tools, including download_arxiv. Retrieves the searcher instance and calls its download_pdf method.

  async def _download(
      searcher_name: str, 
      paper_id: str, 
      save_path: Optional[str] = None
  ) -> str:
      """通用下载函数"""
      if save_path is None:
          save_path = get_download_path()
      
      searcher = SEARCHERS.get(searcher_name)
      if not searcher:
          return f"Error: Unknown searcher {searcher_name}"
      
      try:
          return searcher.download_pdf(paper_id, save_path)
      except NotImplementedError as e:
          return str(e)
      except Exception as e:
          logger.error(f"Download failed for {searcher_name}: {e}")
          return f"Error downloading: {str(e)}"

• paper_find_mcp/academic_platforms/arxiv.py:116-157 (helper)

  Core implementation of PDF download in ArxivSearcher.download_pdf method. Downloads from https://arxiv.org/pdf/{paper_id}.pdf, handles caching, sanitizes filename, and saves to specified directory.

  def download_pdf(self, paper_id: str, save_path: str) -> str:
      """下载 arXiv 论文 PDF
      
      Args:
          paper_id: arXiv 论文 ID (例如 '2106.12345')
          save_path: 保存目录
          
      Returns:
          str: PDF 文件路径
          
      Raises:
          RuntimeError: 下载失败时抛出
      """
      # 确保目录存在
      os.makedirs(save_path, exist_ok=True)
      
      # 构建文件路径
      # 处理带版本号的 ID (例如 2106.12345v2)
      safe_id = paper_id.replace('/', '_').replace(':', '_')
      output_file = os.path.join(save_path, f"{safe_id}.pdf")
      
      # 检查文件是否已存在
      if os.path.exists(output_file):
          logger.info(f"PDF already exists: {output_file}")
          return output_file
      
      # 下载 PDF
      pdf_url = f"https://arxiv.org/pdf/{paper_id}.pdf"
      
      try:
          response = requests.get(pdf_url, timeout=60)
          response.raise_for_status()
          
          with open(output_file, 'wb') as f:
              f.write(response.content)
          
          logger.info(f"PDF downloaded: {output_file}")
          return output_file
          
      except requests.RequestException as e:
          raise RuntimeError(f"Failed to download PDF: {e}")

• paper_find_mcp/server.py:75-85 (registration)

  Registration of searcher instances, including 'arxiv': ArxivSearcher(), which provides the download_pdf implementation used by download_arxiv.

  SEARCHERS = {
      'arxiv': ArxivSearcher(),
      'pubmed': PubMedSearcher(),
      'biorxiv': BioRxivSearcher(),
      'medrxiv': MedRxivSearcher(),
      'google_scholar': GoogleScholarSearcher(),
      'iacr': IACRSearcher(),
      'semantic': SemanticSearcher(),
      'crossref': CrossRefSearcher(),
      'repec': RePECSearcher(),
  }