Version 2.1.48

Create and work in isolated git worktrees directly from Claude Code, with full session management and cleanup prompts.

# Start Claude Code with a new worktree
claude --worktree
claude -w

# Start with a named worktree
claude --worktree=my-feature

# Combine with tmux for parallel sessions
claude --worktree --tmux

• Creates a new git worktree in .claude/worktrees/ with a dedicated branch based on HEAD
• Automatically switches the session's working directory to the worktree
• On session exit, prompts to keep or remove the worktree and associated tmux session
• Symlinks configured directories (like node_modules) from main repo to avoid disk bloat
• Copies settings.local.json and configures git hooks from the main repository
• The worktree branch is automatically deleted when removing the worktree

New -w, --worktree [name] flag and CreateWorktree tool (search for "Create a new git worktree for this session")

A new built-in tool that allows Claude to create worktrees mid-session when users request isolated work.

User: "Start a worktree for this feature"
User: "Work in isolation on a separate branch"

• Tool activates when user asks to "work in isolation" or "start a worktree"
• Must be in a git repository and not already in a worktree
• Creates worktree with optional custom name
• Session automatically switches to the new worktree directory

Tool description (search for "Use this tool when the user asks to work in isolation")

A new hook type that sends HTTP POST requests instead of executing shell commands, enabling webhook-style integrations.

Usage (in settings.json or CLAUDE.md):

{
  "hooks": {
    "PreToolUse": [{
      "type": "http",
      "url": "https://your-server.com/hook",
      "headers": {
        "Authorization": "Bearer $MY_TOKEN"
      },
      "timeout": 30
    }]
  }
}

• Supports environment variable expansion in headers ($VAR_NAME or ${VAR_NAME} syntax)
• Configurable timeout per request
• JSON response parsing with optional logging
• Works with all hook events including the new ConfigChange event

New http hook type definition (search for "HTTP hook type")

A new hook event that fires when configuration files change during a session, allowing validation and blocking of config changes.

• Fires when skills, settings, or CLAUDE.md files are modified
• Can block changes by returning exit code 2
• Input includes source (user_settings, project_settings, etc.) and file_path
• Useful for enforcing configuration policies

New ConfigChange hook event (search for "ConfigChange")

Exclude specific CLAUDE.md files from loading using glob patterns or absolute paths.

Usage (in settings.json):

{
  "memory": {
    "excludePatterns": [
      "/home/user/monorepo/CLAUDE.md",
      "**/node_modules/**/CLAUDE.md",
      "**/some-dir/.claude/rules/**"
    ]
  }
}

• Uses picomatch for glob pattern matching
• Patterns match against absolute file paths
• Only applies to User, Project, and Local memory types (Managed/policy files cannot be excluded)

New excludePatterns setting (search for "Glob patterns or absolute paths of CLAUDE.md files to exclude from loading")

Automatically create tmux sessions when starting worktrees, with iTerm2 native pane support.

claude --worktree --tmux
claude -w --tmux=classic  # Use traditional tmux instead of iTerm2 integration

• Creates a tmux session for parallel worktree work
• Uses iTerm2 native panes when available for better integration
• Use --tmux=classic for traditional tmux behavior
• Session management options on exit: keep both, keep worktree only, or remove all

New --tmux flag (search for "Create a tmux session for the worktree")

Added explicit descriptions for model thinking capabilities in the schema.

• New effortLevels field describes available effort levels for models
• New supportsAdaptiveThinking field indicates whether a model supports adaptive thinking (Claude decides when and how much to think)

New schema descriptions (search for "Whether this model supports adaptive thinking")

Improved git diff generation when creating issues, with better handling of edge cases.

• Handles shallow clones gracefully with HEAD-only mode
• Falls back to HEAD-only mode when no remote or merge-base is found
• Captures untracked files with size limits (500MB per file, 5GB total)
• Excludes binary files from untracked file capture
• Filters out excessively large files automatically

New shallow clone detection (search for "Shallow clone detected, using HEAD-only mode for issue")

Caches MCP servers that need authentication to reduce redundant connection attempts.

• Stores needs-auth status in mcp-needs-auth-cache.json
• Skips connection attempts for cached servers
• Logged as "Skipping connection (cached needs-auth)"

New cache file (search for "mcp-needs-auth-cache.json")

Better messaging for background agent management.

• New "Press again to kill all background agents" message for confirmation
• Clearer output file instructions

New UI text (search for "Press again to kill all background agents")

Better feedback when opening worktrees or projects in IDEs.

• Clearer messages for manual IDE opening
• Specific messaging for worktree vs project contexts

New message handling (search for "Please open the")

• Fixed path traversal detection (search for "path traversal detected")
• Added validation for non-empty strings and patterns (search for "Expected a non-empty string")

The experimental mcp-cli command-line interface for MCP servers has been removed.

• The ENABLE_EXPERIMENTAL_MCP_CLI environment variable is no longer recognized
• The mcp-cli command (info, call, servers, tools, grep, resources, read) is removed
• MCP tools continue to work through the normal tool interface

Impact: If you relied on mcp-cli commands in bash scripts or hooks, migrate to using MCP tools through Claude's standard tool interface.

Removal of mcp-cli infrastructure (removed strings: "mcp-cli info", "mcp-cli call", "ENABLE_EXPERIMENTAL_MCP_CLI")

The worktree feature requires being in a git repository and having git installed. Tmux integration requires tmux to be installed (sudo apt install tmux on Linux). iTerm2 users will get native pane integration when using --tmux without the =classic suffix.