MCP Server | Logging and Progress

While a request is being processed, the server can send log messages (notifications/message) and progress notifications (notifications/progress) to the client that made the request. Use the overloads of SendLogMessage and SendNotificationProgress that receive the session of the current request.

 

• SendLogMessage(aSession, aLevel, aLogger, aData): sends a log entry related to the current request.
• SendNotificationProgress(aSession, aProgressToken, aProgress, aTotal, aMessage): reports the progress of the current request. The progress token is sent by the client in the request _meta and is available in aRequest.ProgressToken.

 

2026-07-28 clients

Modern requests have no session, so the notifications are streamed in the response of the same request. When the client accepts text/event-stream, the HTTP response is sent as a Server-Sent Events stream with every notification followed by the final result. Over stdio the notifications are written before the response.

• A log message is only sent when the client requested logs for that request with logLevel in _meta, and the level of the message is equal to or higher than the requested level.
• A progress notification is only sent when the request contains a progress token.

 

Legacy clients

For 2025-11-25 and older clients the overloads behave like the methods without session: the log level is the one set by the client with logging/setLevel, and the notifications are delivered through the session streams, which requires TransportOptions.HttpStreamable.Enabled.

 

procedure TMainForm.MCPServerMCPRequestTool(Sender: TObject;
  const aSession: TsgcAI_MCP_Session; const aRequest: TsgcAI_MCP_Request_ToolsCall;
  const aResponse: TsgcAI_MCP_Response_ToolsCall);
var
  i: Integer;
begin
  MCPServer.SendLogMessage(aSession, aimcpllInfo, 'import', 'Import started');
  for i := 1 to 5 do
  begin
    ImportChunk(i);
    if aRequest.ProgressToken <> '' then
      MCPServer.SendNotificationProgress(aSession, aRequest.ProgressToken, i, 5,
        Format('Chunk %d of 5', [i]));
  end;
  MCPServer.SendLogMessage(aSession, aimcpllInfo, 'import', 'Import finished');
  aResponse.Result.Content.AddText('5 chunks imported');
end;