{"version":"2.1.284","anchor":"file-sync-now-says-when-anthropic-has-switched-it-off","canonical_anchor":"file-sync-now-says-when-anthropic-has-switched-it-off","heading":"Cloud file sync signs uploads with your device and says when Anthropic has switched it off","tier":"notice","area":"Cloud Sessions","url":"https:\/\/changelogs.core-directive.com\/v\/2.1.284\/e\/file-sync-now-says-when-anthropic-has-switched-it-off","release_url":"https:\/\/changelogs.core-directive.com\/v\/2.1.284","markdown":"### Cloud file sync signs uploads with your device and says when Anthropic has switched it off\n\nFile sync for claude --cloud sessions now signs uploads with the bound device's key and shows a clear message when Anthropic has switched sync off\n\n**Unclear.** Whether Anthropic's server sends this refusal today cannot be told from Claude Code itself.\n\n**What**\n\nWith `--cloud`, Claude Code can keep a folder on your machine in sync with a cloud session. That sync has been hardened.\n\n- Device signing: file uploads (put, upload-begin and upload-commit) are now signed with the key of the device the session is bound to, and carry `device_attestation` and `device_attestation_issued_at`. Attach and headless attach pass the bound device's id and signer through.\n\n- No usable device key: a folder session with no bound device id stops file sync with reason `device_key_unavailable`, and an unsigned result maps to the same cause. A separate message covers a machine that cannot sign as the bound device.\n\n- Off switch: when the server refuses with the reason \"synced_file_lane_denied\" (HTTP 400), the cause is now `switched_off_by_anthropic` instead of the general \"sync is not available for this session\". You see \"file sync was switched off on Anthropic's side for now; the cloud session keeps whatever files it has - re-open the session later to try again\", or, at attach, \"File sync was not started: it is switched off on Anthropic's side for now. Attach the folder again later to retry.\" This shows as a warning, and the paused or refused status elsewhere in the sync view reflects it.\n\n- The sync worker's device-status, failure-tracking and restore logic was rewritten. It stands down after 3 reads without a status and adds held-turn and back-online states.\n\n- The attach path checks `tengu_violin_soundpost`, with a fallback of off. No reading of it has been taken under this release.\n\n**Why**\n\nCloud file writes are now tied to the machine the session is bound to, so on a machine without a usable device key sync stands down instead of uploading. When sync stops on Anthropic's side, you can tell that apart from a problem on your own machine and know a later retry may work.\n\n- Area: Cloud Sessions\n- Tier: You'll notice\n- Useful: 2\/5\n- Signal: 3\/5"}