The agent works with the Cloud over the WebDAV protocol through webdav.cloud.mail.ru — the same way the cloud is mounted as a network drive. It lists folders and files, reads metadata — name, size, type, modification date — finds a document by part of its name and shows how much space is used and how much is left. That is also what makes an export readable: the file is fetched whole and crunched, not retold by its file name.

Unlike Yandex Disk, a file goes in here as contents: the agent sends the bytes directly with PUT, no external link is needed, so the result of a calculation comes back as a file rather than as a download address. Copying and moving are performed synchronously by WebDAV — the response arrives once the operation is already finished, so a half-way «done» is impossible here by construction.

The protocol has a flip side the agent does not hide. WebDAV has no server-side search: the agent walks the tree folder by folder and keeps the walk inside bounds — on depth, on folder count and on the number of matches. Once it hits a bound it says the list is incomplete instead of passing a partial result off as exhaustive. Public links and the trash are absent from the protocol too — those are features of the Cloud itself, not of WebDAV.

What gets connected is not the account password but a separate app password, and it is revoked in the Mail.ru settings on its own, without changing the main one. Access is limited to the Cloud of the mailbox whose password is connected. The agent asks before overwriting a file with the same name and before deleting: a delete removes a file and a whole folder with everything in it, and the agent cannot bring it back the way it went — the protocol has no restore, and whether a copy sits in the Cloud's own trash is not visible to it.