What
Claude Code can start a spare copy of itself ahead of time so it is ready when needed. While such a spare is waiting to be claimed (its state is "parked"), it now skips:
- session setup
- the context measurements run
- naming the session and checking for other running sessions
Two startup steps, logging the permission settings and setting up plugins, no longer run in line with the rest of startup. In headless runs (started with -p, which prints a result without the interactive screen) they are tracked as named steps, and plugin setup stops early on shutdown. In interactive runs, the permission settings are logged a little later or when the app cleans up.
Why
A spare that has not been used yet does not do work that belongs to a real session.