Bad sandbox settings no longer break the sandbox until restart

What

The sandbox is the protected environment Claude Code can run commands in. Claude Code builds its sandbox setup from your settings. It now handles settings that cannot be turned into a working setup more gracefully:

• At startup, if the sandbox settings cannot be built, Claude Code records a configBuildFailed state and waits for your next settings change to try again. It no longer counts the failure as a general sandbox startup failure.
• The configBuildFailed state is cleared again when your settings change.
• If the sandbox is required and its setup failed to build, the error now reads "Fix the sandbox settings to retry (a --settings file is pinned for the process: restart)." It used to say only "Restart to retry."
• If the sandbox is already running and a later edit to your settings is invalid, Claude Code keeps the setup it is running and logs "Sandbox config rebuild skipped, keeping the running config". Before, settings updates rebuilt the setup with no guard against errors.

The exception is settings passed with the --settings flag, a command-line option that points Claude Code at a settings file or inline settings for one session. Those are fixed for the life of the process, so to change them you still restart.

Why

A typo in your sandbox settings is less disruptive. You can usually fix it in place without restarting, and a mistake made while the sandbox is running leaves the working sandbox as it was.