MCP-Server-IETF

Instructions

Implementation Reference

• src/mcp_server_ietf/server.py:68-91 (handler)

  The main async handler function implementing the logic for the 'get_ietf_doc' MCP tool. It retrieves the server context, calls the get_rfc_document helper with parameters, logs the result, and returns the document data.
  async def get_ietf_doc( ctx: Context, number: int, start_line: int = 1, max_lines: int = DEFAULT_MAX_LINES, ) -> Dict[str, Any]: """ Get an RFC document by its number in RFC editor Index with pagination support Args: number: The RFC number str (e.g., "1234") start_line: The line number to start from (default: 1) max_lines: Maximum number of lines to return (default: 200) Returns: A dictionary containing the document content and metadata """ server_ctx = ctx.request_context.lifespan_context data = get_rfc_document(str(number), start_line, max_lines, CACHE_DIR, server_ctx) logger.debug(f"get_doc: {data}") return data
• src/mcp_server_ietf/server.py:67-67 (registration)

  Registers the get_ietf_doc function as a tool on the FastMCP server instance.
  @mcp.tool()
• src/mcp_server_ietf/rfc_parser.py:134-214 (helper)

  Core helper function that implements the document retrieval logic: input validation, index lookup, download/caching, pagination, metadata extraction including page info, and structured output.
  def get_rfc_document( rfc_number: str, start_line: int = 1, max_lines: int = 200, cache_dir: str = CACHE_DIR, index_data: Optional[RFCIndexData] = None ) -> Dict[str, Any]: """ Get an RFC document by its number with pagination support Args: rfc_number: The RFC number (e.g., "1234") start_line: The line number to start from (default: 1) max_lines: Maximum number of lines to return (default: 200) cache_dir: Directory to store cached files index_data: Optional pre-loaded index data Returns: A dictionary containing the document content and metadata """ # Validate input if not rfc_number.isdigit(): return {"error": "RFC number must be a number"} if start_line < 1: return {"error": "start_line must be 1 or greater"} if max_lines < 1: return {"error": "max_lines must be 1 or greater"} # Get index data if not provided if index_data is None: index_path = download_rfc_index(cache_dir) index_data = parse_rfc_index(index_path) # Check if RFC exists in our index if rfc_number not in index_data.rfc_titles: return {"error": f"RFC {rfc_number} not found in index"} # Download RFC if needed try: doc_path = download_rfc(rfc_number, cache_dir) except Exception as e: return {"error": str(e)} # Read and paginate the document with open(doc_path, "r", encoding="utf-8") as f: all_lines = f.readlines() total_lines = len(all_lines) # Validate start_line if start_line > total_lines: return {"error": f"start_line ({start_line}) exceeds document length ({total_lines})"} # Calculate pagination end_line = min(start_line + max_lines - 1, total_lines) paginated_lines = all_lines[start_line-1:end_line] paginated_content = ''.join(paginated_lines) # Check if truncated truncated = end_line < total_lines # Extract page numbers if available by scanning the content page_info = extract_page_info(paginated_content) # Basic metadata title = index_data.rfc_titles.get(rfc_number, "Unknown title") return { "content": paginated_content, "title": title, "path": doc_path, "start_line": start_line, "end_line": end_line, "max_lines": max_lines, "total_lines": total_lines, "truncated": truncated, "truncated_at_line": end_line if truncated else None, "page_info": page_info, "next_chunk_start": end_line + 1 if truncated else None }
• src/mcp_server_ietf/rfc_parser.py:14-20 (schema)

  Dataclass defining the structure for RFC index data, used by get_rfc_document to check RFC existence and retrieve titles.
  @dataclass class RFCIndexData: """Data structure for RFC index information""" index_path: str docs_count: int rfc_titles: Dict[str, str] # Map of RFC number to title