New --proactivity flag sets how much Claude does on its own at startup

A flag is an option you add to the command that starts Claude Code. The new --proactivity flag chooses how much Claude acts on its own and takes one of three levels, ask, default or proactive, for example claude --proactivity ask. It is hidden from claude --help but is read if you type it.

The level is picked in this order:

• a level handed over when Claude Code restarts itself
• the value given with --proactivity
• default

The code has a step for a level saved from an earlier session, but in this build it always comes back empty, so nothing is remembered between sessions.

Without the flag the feature stays off. With it, the selector is on unless CLAUDE_CODE_DISABLE_PROACTIVITY is set, the server flag tengu_proactivity_selector is off (when the server sends nothing, it is on), Claude Code runs with --bare, or CLAUDE_CODE_DISABLE_ATTACHMENTS is set. If the selector is off and you asked for ask without also giving a permission mode, Claude Code starts in manual mode (the default permission mode) and shows "--proactivity ask isn't available here · Started in manual mode".

When it is on, the level does two things:

• It adds a note Claude reads. ask (labelled low) tells Claude to confirm before changing anything, agree a plan first, and never commit, push or open a pull request unless you confirm it. default (medium) tells it to ask only when it truly cannot go on, and still not to commit or push unasked. proactive (high) tells it not to ask questions, to commit, push and open pull requests when that is the natural next step, to pick up follow-up work on its own, and to schedule check-ins instead of waiting on slow things. The note says it does not override plan mode, the permission mode, or the rules about destructive actions.
• It picks the starting permission mode, unless you gave one yourself with --permission-mode or similar. ask starts in auto mode where auto mode is available, otherwise in the default mode. proactive starts in auto mode where available, otherwise in accept-edits mode. At startup it never picks bypass mode, and default leaves the mode alone.

There is no keyboard shortcut to switch levels in this build. A program driving Claude Code through the SDK can change it mid-session with a set_proactivity_level request, once it has turned levels on for the session. That path can reach bypass mode: switching to proactive picks bypass when the session allows it (started with --dangerously-skip-permissions or --allow-dangerously-skip-permissions) unless the request sets offer_bypass to false. Cloud-hosted sessions refuse the request.