What
Environment variables are named values that programs read from their surroundings. settings.env is the setting that lists extra ones for Claude Code. When settings.env changes while Claude Code is running, Claude Code now calls a helper that reapplies the environment variables from your config, plus one other step.
The explicit step that saved CLAUDE_CODE_REPL beforehand and restored it afterwards has been removed.
Why
Environment changes are now handled by reapplying the config as a whole rather than by protecting one variable by name. If you rely on CLAUDE_CODE_REPL, it is worth checking that it still has the value you expect after changing settings.env mid-session.
Names in the bundlesettings.env
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 whether the new helper keeps `CLAUDE_CODE_REPL` intact.