What
Claude Code now sorts every incoming message into one of nine origin categories for internal telemetry: human, sdk, scheduled, task_notification, auto_continuation, peer, host_synthetic, system, or unknown. It works this out from more detailed signals than before, including what woke the session up and specific origin types like a scheduled trigger, a peer sending a message, or a relay between projects.
Why
This is internal bookkeeping used for telemetry rather than something a user configures directly. Sorting messages this precisely lets Claude Code's own systems tell apart, for example, a message a human typed from one generated by a scheduled job or forwarded from another session.