What's new in Claude Code v2.1.133
Five quiet but consequential changes for advanced users: subagents finally inherit project, user, and plugin skill discovery; hooks see the active effort level via JSON input and a $CLAUDE_EFFORT env var; new worktree.baseRef setting picks whether worktrees branch from origin/ or local HEAD; admins get sandbox.bwrapPath and sandbox.socatPath for non-standard Linux/WSL deployments; and SDK hosts get parentSettingsBehavior for managed-settings merge control.
Subagents now discover project, user, and plugin skills
Why: Subagents were skill-blind — they only saw built-in tools, not the skills the parent session had access to.
What: Subagents now inherit skill discovery from project, user, and plugin sources.
How: No action — subagents pick up skills automatically.
Hooks now receive effort.level and $CLAUDE_EFFORT
Why: Hooks couldn't tell which effort level a session was running at, so they couldn't tailor behavior to high/medium/low effort.
What: Hook JSON input now includes effort.level, and $CLAUDE_EFFORT is exposed to hook subprocesses.
How: Read input.effort.level in hook JSON or $CLAUDE_EFFORT in hook scripts.
Why: Worktrees default to branching from origin/, but team workflows that want HEAD-based branches had no opt-in.
What: New worktree.baseRef setting picks whether new worktrees branch from origin/ or local HEAD.
How: Set "worktree": { "baseRef": "head" } in .claude/settings.json.
sandbox.bwrapPath and sandbox.socatPath managed settings
Why: Linux/WSL sandboxing relies on bwrap and socat, but their paths can vary across distributions and managed deployments couldn't override.
What: Two new managed settings let admins point Claude Code at custom bwrap and socat binaries.
How: Set "sandbox": { "bwrapPath": "...", "socatPath": "..." } in managed settings.
parentSettingsBehavior — SDK managed-settings merge policy
Why: SDK hosts using managedSettings had no way to control how parent settings merged with child overrides.
What: New admin-tier parentSettingsBehavior key configures the merge policy for managed-settings inheritance.
How: Set "parentSettingsBehavior" in the SDK host's managed settings.
Hosts: Alex Chen & Sarah Kim · Generated from the official Claude Code CHANGELOG.
Full changelog: github.com/anthropics/claude-code/CHANGELOG.md
Claude Code docs: docs.claude.com/en/docs/claude-code
- (00:00) - Subagents discover skills
(00:58) - Hooks see effort.level(01:29) - worktree.baseRef setting(02:22) - Sandbox bwrapPath / socatPath(02:50) - parentSettingsBehavior