What
In headless mode (Claude Code driven by another program, for example through the SDK, instead of by a person at a terminal), incoming user messages can be held back until Claude Code is ready. A message flagged as the client's own first-turn message now waits in a separate queue. Other messages now also wait on a new first-turn gate, and closing input waits for both. The cli_user_frame_parked telemetry gains own_first_turn_message and first_turn_gate.
Why
The program's own first message is kept apart from other incoming messages, so the first turn is handled before anything that arrives alongside it.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding does not say what ordering problem, if any, this change fixes for SDK users.