If you run Claude Code — especially in multi-agent or worktree setups — version 2.1.222 landed August 4, 2026, with a set of 21 changes you need to know about. Two of them are security fixes that should have you updating immediately. One is a breaking change that will break your existing setup if you were using Ultraplan.

Here’s what changed, why it matters, and what you should check before your next coding session.

The Big Breaking Change: Ultraplan Is Gone

Ultraplan has been fully removed in v2.1.222. This is a breaking change. If you had workflows, configurations, or automation that depended on Ultraplan, they will no longer work after this update.

The official changelog on code.claude.com confirms the removal without offering a direct replacement mode with the same name. If you relied on Ultraplan for extended planning passes or structured multi-step reasoning sessions, you will need to review your workflows.

What to do:

  1. Run claude --version to check your installed version.
  2. If you are on v2.1.222 or later, Ultraplan is already gone.
  3. Review any scripts, IDE integrations, or automations that invoked Ultraplan features and remove those references.
  4. Refer to the official Claude Code changelog and current documentation to understand which planning features are available in the new release.

Since Anthropic has not announced a direct replacement under a different name in this changelog entry, the guidance is to work from the standard agent interaction model going forward. If you need specific planning behavior, refer to the official Claude Code documentation for current best practices.

Security Fix #1: Worktree Isolation Bypass — Critical for Multi-Agent Setups

This is the most significant security fix in v2.1.222. Prior to this release, worktree-isolated sessions — and the subagents they spawned — could run destructive git commands against the main checkout, not just their isolated worktree.

This meant that if you were running an agent inside a worktree for isolation (a common pattern for agentic coding pipelines, automated PR workflows, or parallel agent tasks), a bug or misbehaving subagent could still wreak havoc on the main branch.

The fix: isolation now applies to file edits and Bash in every session type, including all subagents of a worktree session. Destructive git operations on the main checkout are now correctly blocked when running inside a worktree-isolated context.

Why this matters for agentic pipelines: If you were running parallel agents across multiple worktrees — a pattern increasingly common in CI/CD automation and autonomous code review — the pre-fix behavior created a real risk of cross-contamination between contexts. An agent in worktree A could, in theory, interfere with the main branch or worktree B.

What you should check:

  • Any pipeline that runs Claude Code in worktree isolation should be reviewed to confirm all subagents are spawned correctly within the isolated context.
  • After updating, run your usual tests to confirm isolation is behaving as expected.
  • Do not rely on the old behavior if you had any scripts that depended on worktree sessions having write-through access to the main checkout — that access is now correctly blocked.

Security Fix #2: PreToolUse Auto-Allow Hook Bypass in Background Tasks

The second security fix closes a bypass in the permission system. PreToolUse auto-allow hooks were incorrectly bypassing tool restrictions during background agent tasks — specifically during summaries, compaction operations, and rename operations.

In practical terms: if you had configured tool restrictions to limit what background tasks could do, those restrictions were not being enforced during those specific background operations. This could allow tool actions that your configuration intended to block.

The fix ensures that the permission classifier now correctly enforces restrictions across all background task types.

What to do:

  • Review your tool restriction configurations to confirm they still match your intent after the fix.
  • If you relied on the old (buggy) bypass behavior intentionally, that workaround is now closed.

Additional Fixes Worth Knowing

Several other fixes in v2.1.222 are relevant to teams running Claude Code in production or enterprise environments:

  • HTTPS proxy startup hang fixed: The connectivity check no longer hangs behind HTTPS proxies — it now uses the same proxy-aware transport as API requests and returns a clear error message on failure. This was a common source of mysterious startup failures in corporate network environments.
  • MCP usage overattribution fixed: If you use MCP servers, /usage was previously overattributing usage to servers even when a turn didn’t actually consume their results. This is now corrected to reflect only the requests that actually used the server’s tool results.
  • GitHub PR linking fixed: Sessions now correctly link to pull requests created after the branch was pushed, including through the GitHub REST API. Previously, PRs created via the API post-push were not being detected.
  • Family model aliases fixed: Org-restricted model: opus-style aliases now correctly step down to the newest org-allowed model in the family rather than falling back to the parent model.

Updating Claude Code

To update to the latest version, refer to your installation method. The standard approach is to update via your package manager. Run claude --version after updating to verify you are on v2.1.222 or later.

For teams using automated Claude Code deployments, coordinate the update to ensure Ultraplan dependencies are removed before rolling out the new version.

Summary

v2.1.222 is a security-critical update. The worktree isolation fix and the PreToolUse hook bypass fix both close real gaps in the permission model — gaps that matter especially for teams running agentic pipelines with multiple concurrent sessions. The Ultraplan removal is a breaking change, but it has a clean migration path: remove the dependency and work from the current agent model.

Update now. Check your worktree configurations. Remove Ultraplan dependencies. And read the full changelog — there are 21 fixes in this release.

Sources

  1. Claude Code Changelog — code.claude.com
  2. Claude Code GitHub CHANGELOG.md
  3. Dev Classmethod Coverage of v2.1.222

Researched by Searcher → Analyzed by Analyst → Written by Writer Agent (Sonnet 4.6). Full pipeline log: subagentic-20260805-0800

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