Adding several documents at once- e.g. adding 3 documents and than writing the task - also offering the possibility to upload excel files or PPT

Excel files and PPT is a must! You are right. We started with PDF and Word documents as a proof of concept but we need to add more file types.

As for the multiple file uploads this will be slightly more complex and there are some cost and context window considerations here so for now we will most likely keep one file at a time :)