Paperlib MCP

Instructions

Implementation Reference

• src/paperlib_mcp/tools/fetch.py:439-579 (handler)

  Handler function that implements the logic for updating document metadata in the database. Decorated with @mcp.tool() to register it as an MCP tool.

  @mcp.tool()
  def update_document(
      doc_id: str,
      title: str | None = None,
      authors: str | None = None,
      year: int | None = None,
      venue: str | None = None,
      doi: str | None = None,
      url: str | None = None,
  ) -> dict[str, Any]:
      """更新指定文档的元数据
      
      根据 doc_id 更新文档的元数据信息。只有提供的字段会被更新，
      未提供的字段保持原值不变。
      
      Args:
          doc_id: 文档的唯一标识符（SHA256 哈希）
          title: 新的论文标题
          authors: 新的作者列表
          year: 新的发表年份
          venue: 新的期刊/会议名称
          doi: 新的 DOI 标识符
          url: 新的论文链接
          
      Returns:
          更新结果，包含：
          - success: 是否成功
          - doc_id: 文档 ID
          - updated_fields: 更新的字段列表
          - document: 更新后的文档信息
      """
      try:
          # 检查文档是否存在
          existing = query_one(
              "SELECT doc_id FROM documents WHERE doc_id = %s",
              (doc_id,)
          )
          
          if not existing:
              return {
                  "success": False,
                  "error": f"Document not found: {doc_id}",
                  "doc_id": doc_id,
              }
          
          # 收集要更新的字段
          update_fields = []
          update_values = []
          updated_field_names = []
          
          if title is not None:
              update_fields.append("title = %s")
              update_values.append(title)
              updated_field_names.append("title")
          
          if authors is not None:
              update_fields.append("authors = %s")
              update_values.append(authors)
              updated_field_names.append("authors")
          
          if year is not None:
              update_fields.append("year = %s")
              update_values.append(year)
              updated_field_names.append("year")
          
          if venue is not None:
              update_fields.append("venue = %s")
              update_values.append(venue)
              updated_field_names.append("venue")
          
          if doi is not None:
              update_fields.append("doi = %s")
              update_values.append(doi)
              updated_field_names.append("doi")
          
          if url is not None:
              update_fields.append("url = %s")
              update_values.append(url)
              updated_field_names.append("url")
          
          if not update_fields:
              return {
                  "success": False,
                  "error": "No fields to update. Please provide at least one field.",
                  "doc_id": doc_id,
              }
          
          # 添加 updated_at
          update_fields.append("updated_at = now()")
          
          # 构建并执行 UPDATE 语句
          update_sql = f"""
              UPDATE documents
              SET {', '.join(update_fields)}
              WHERE doc_id = %s
              RETURNING 
                  doc_id, title, authors, year, venue, doi, url,
                  pdf_bucket, pdf_key, pdf_sha256,
                  created_at::text, updated_at::text
          """
          update_values.append(doc_id)
          
          with get_db() as conn:
              with conn.cursor() as cur:
                  cur.execute(update_sql, tuple(update_values))
                  updated_doc = cur.fetchone()
          
          if not updated_doc:
              return {
                  "success": False,
                  "error": f"Failed to update document: {doc_id}",
                  "doc_id": doc_id,
              }
          
          return {
              "success": True,
              "doc_id": doc_id,
              "updated_fields": updated_field_names,
              "document": {
                  "doc_id": updated_doc["doc_id"],
                  "title": updated_doc["title"],
                  "authors": updated_doc["authors"],
                  "year": updated_doc["year"],
                  "venue": updated_doc["venue"],
                  "doi": updated_doc["doi"],
                  "url": updated_doc["url"],
                  "pdf_bucket": updated_doc["pdf_bucket"],
                  "pdf_key": updated_doc["pdf_key"],
                  "pdf_sha256": updated_doc["pdf_sha256"],
                  "created_at": updated_doc["created_at"],
                  "updated_at": updated_doc["updated_at"],
              },
          }
          
      except Exception as e:
          return {
              "success": False,
              "error": str(e),
              "doc_id": doc_id,
          }

• src/paperlib_mcp/server.py:36-36 (registration)

  Invocation of register_fetch_tools(mcp) which registers the update_document tool (and other fetch tools) with the MCP server.

  register_fetch_tools(mcp)