Bookstore MCP Server

Instructions

Implementation Reference

• src/bookstore_mcp/server.py:60-84 (handler)

  The buy_book tool handler function, decorated with @mcp.tool() for registration. It handles purchasing books by checking stock, updating count, and saving to JSON.

  @mcp.tool()
  def buy_book(book_id: int, quantity: int = 1):
      """Buy a book."""
      if quantity <= 0:
          return {"success": False, "error": "Quantity must be > 0"}
  
      books = load_books()
      book = next((b for b in books if b["id"] == book_id), None)
  
      if not book:
          return {"success": False, "error": f"Book {book_id} not found"}
  
      if book["count"] < quantity:
          return {"success": False, "error": f"Only {book['count']} available"}
  
      book["count"] -= quantity
  
      if save_books(books):
          return {
              "success": True,
              "message": f"Purchased {quantity} of '{book['title']}'",
          }
      else:
          return {"success": False, "error": "Save failed"}