A new effort field was added to the hook event JSON payload. It contains a level property with the active effort level for the turn ("low", "medium", "high", "xhigh", or "max"). If the requested effort exceeds what the current model supports, the field reflects the downgraded level actually used. Present for events like PreToolUse, PostToolUse, Stop, and SubagentStop. The level is also exposed as the $CLAUDE_EFFORT environment variable. [line 504] [Source]
--resume now automatically restores the permission mode that was active when a tool was deferred — you no longer need to pass --permission-mode again on resume. The exceptions are plan and bypassPermissions, which are never carried over. Passing --permission-mode explicitly on resume overrides the restored value. [line 1170] [Source]
Clarified that the /branch confirmation now prints two session IDs: the new branch you are now in and the original, making it easier to return to the original session. [line 91] [Source]
New requirement: before using --worktree in a directory for the first time, you must accept the workspace trust dialog by running claude once in that directory. If trust has not been accepted, --worktree exits with an error. [line 45] [Source]
The base branch for worktrees is now configured via a new worktree.baseRef setting in settings.json, accepting "fresh" (default, branches from origin/HEAD) or "head" (branches from local HEAD, useful for subagents needing in-progress work). The previous approach of using git remote set-head commands has been replaced. [line 51] [Source]
New feature: --worktree now accepts a PR number prefixed with # (e.g. claude --worktree "#1234") or a full GitHub PR URL to create a worktree branching from that pull request. Claude Code fetches pull/<number>/head from origin and creates the worktree at .claude/worktrees/pr-<number>. [line 61] [Source]