LibraLM MCP Server

Instructions

Implementation Reference

• libralm_mcp_server.py:130-156 (handler)

  The main handler function for the 'list_books' tool. It fetches the list of books from the LibraLM API endpoint '/books', parses the response into BookInfo models, sorts them by title, and returns the list. Includes error handling and debug logging.

  @mcp.tool()
  def list_books() -> List[BookInfo]:
      """List all available books with their basic information"""
      try:
          # Debug: Check what API key and URL we're using
          api_key = get_api_key()
          api_url = get_api_base_url()
          print(f"DEBUG: Using API URL: {api_url}")
          print(f"DEBUG: API key present: {bool(api_key)}, length: {len(api_key) if api_key else 0}")
  
          data = _make_api_request("/books")
          print(f"DEBUG: Received data: {data}")
  
          books = []
  
          for book_data in data.get("books", []):
              books.append(BookInfo(**book_data))
  
          print(f"DEBUG: Returning {len(books)} books")
          return sorted(books, key=lambda x: x.title)
      except Exception as e:
          print(f"ERROR listing books: {str(e)}")
          import traceback
          traceback.print_exc()
          # Raise the error instead of silently returning empty list
          raise ValueError(f"Error listing books: {str(e)}")

• libralm_mcp_server.py:86-101 (schema)

  Pydantic BaseModel defining the structure of BookInfo objects returned by the list_books tool, including fields like book_id, title, author, and flags for available content.

  class BookInfo(BaseModel):
      """Book information structure"""
  
      book_id: str
      title: str
      author: Optional[str] = None
      category: Optional[str] = None
      subtitle: Optional[str] = None
      summary: Optional[str] = None
      length: Optional[str] = None
      release_date: Optional[str] = None
      tier: Optional[str] = None
      has_summary: bool
      has_chapter_summaries: bool
      has_table_of_contents: bool

• libralm_mcp_server.py:103-128 (helper)

  Helper function used by list_books to make authenticated GET requests to the LibraLM API, handling authentication, errors, and response parsing.

  def _make_api_request(endpoint: str) -> dict:
      """Make an authenticated request to the LibraLM API"""
      # Get API key and base URL from request context or environment
      api_key = get_api_key()
      base_url = get_api_base_url()
  
      headers = {"x-api-key": api_key, "Content-Type": "application/json"}
  
      url = f"{base_url}{endpoint}"
      response = requests.get(url, headers=headers)
  
      if response.status_code == 401:
          raise ValueError("Invalid API key. Please check your LibraLM API key.")
      elif response.status_code == 404:
          raise ValueError(f"Resource not found: {endpoint}")
      elif response.status_code != 200:
          raise ValueError(
              f"API request failed with status {response.status_code}: {response.text}"
          )
  
      # Handle wrapped response format from Lambda
      result = response.json()
      if isinstance(result, dict) and "data" in result:
          return result["data"]
      return result