You'll notice
A finished background task's result can now be appended into the current assistant turn instead of always starting a new one.
When a background or local-shell task finishes, its result can now be appended as a tool_use into the current assistant turn if that turn already made a tool call, instead of always being inserted as a new synthetic turn. This distinction is tracked via a new telemetry dimension recording whether delivery was an append or a new_turn.