Under the hood
Directory-sync file uploads and downloads are now cryptographically signed before being sent
What
The directory-sync client used for uploading and downloading session files now signs each upload's content, path, and ifMatchSha256 value using a request-signer before sending it. If signing fails, Claude Code logs a warning once and records a telemetry event.
Why
Signing requests helps verify that directory-sync uploads haven't been tampered with in transit. The one-time warning and telemetry event mean a signing failure won't go unnoticed while also not spamming logs.