A guarded file-and-mail layer you host yourself. Every account sits under its own label, the server enforces the rules for each one, and files can be copied, moved and searched between accounts. Google Drive and Gmail, with OneDrive and Dropbox in beta.
you Copy last year's invoices from my personal drive into the company drive.
crossdrive · copy · dry run from personal:/Invoices/2025 to work:/Finance/Invoices 12 files · 1 folder · nothing written yet
assistant One folder with 12 invoices. The originals stay where they are. Copy?
you Yes.
crossdrive · copy done · 12 copied · 0 failed · audited
You need Crossdrive if any of these is true:
If your assistant already lets you connect all your accounts, and you only need to read and draft across a few of them, the built-in connector is simpler: it needs no setup.
Connect your Google accounts and give each a label. Every request names its account, as in work:/Finance/2026 or personal:/Taxes, so nothing is ever done in whichever account happens to be connected.
Copy or move files and whole folder trees from one account to another, with the source trashed only after a move is verified. Find duplicates across accounts, and search every account at once with any account that failed named. Between Google Drive, OneDrive and Dropbox this is beta and not yet tested against live accounts.
Each Gmail account is set to off, draft or send on its own, so a work account can stay draft-only while another may send. New accounts start at draft. Search, read, label and save attachments to the right folder.
It is a remote MCP server with OAuth, meant for any client that can add one, and your tokens stay in your own storage. So far only the Claude desktop app has been verified as a client; Claude Code, ChatGPT and others are untested.
These rules are enforced by the server, not by a prompt. An assistant that misreads a request still cannot get past them.
There is no permanent-delete call in the code. Deleting means moving to the provider's trash, where you can restore it.
Mark any account read-only and the server rejects every write to it, whatever the assistant asks for. Copying out of it streams the files, so not even a temporary permission is added.
Most writes can be previewed with a dry run first. Moves, renames and trashes are logged with an id that undo can roll back.
Each write is recorded with time, client, account, action and file ids; mail entries add recipients and subject. File contents and mail bodies are not logged.
No client gets a token until you sign in and approve it. Clients that should only look can be given read-only access.
Text inside files and emails is returned as untrusted data. Instructions found in a document never become tool calls on their own.
First connect your cloud accounts on the connect page: sign in there to manage this instance, then connect each account under a label. Signing in alone connects nothing.
Then add this URL as a custom connector (remote MCP server) in your client. It will ask you to sign in and approve access.
https://drive.compasscto.com/api/mcp