Claude Code v2.1.221: Focus View, Linux/WSL Masking, and Tooling Fixes
This patch for Claude Code introduces a new Focus view in VSCode, allowing users to toggle chat activity behind an expandable summary, and adds a `mode: "mask"` for sandbox credential files on Linux and WSL for enhanced security. It also includes numerous bug fixes addressing issues with tool permission checks, prompt handling, and session management across different operating systems and environments. The update aims to improve the user experience, security posture, and reliability for developers using Claude Code for coding assistance and automation tasks.
- →Added Focus View for VSCode chat interface
- →Implemented masked sandbox credential files on Linux/WSL
- →Improved tool search for Google Vertex AI
- →Optimized auto mode permission checks and prompt-cache usage
- →Enhanced Windows startup performance and security
Features (2) ›
- Added Focus View for VSCode chat interface
A new Focus view has been added to the VSCode interface, which can be toggled with `Ctrl+Alt+F` or the 'Claude Code: Toggle Focus view' command. This view hides tool activity behind an expandable per-turn summary and includes a live running-tool indicator.
- Implemented masked sandbox credential files on Linux/WSL
The release introduces `mode: "mask"` for sandbox credential files on Linux and WSL. This allows sandboxed commands to read a sentinel copy of the file while the sandbox proxy substitutes real values on egress, enhancing security.
Enhancements (3) ›
- Improved tool search for Google Vertex AI
Tool search on Google Vertex AI has been re-enabled and improved for Claude 4.5-generation and newer models.
- Optimized auto mode permission checks and prompt-cache usage
Permission checks for parallel tool calls in auto mode are now more cache-efficient. The prompt-cache costs for these checks are reduced by reusing the cached conversation prefix across decisions.
- Enhanced Windows startup performance and security
Process creation times on Windows now use a native kernel32 call instead of spawning PowerShell, which reduces prompts from endpoint security tools that gate `powershell.exe`.
Fixes (1) ›
- Fixed Bash tool permission bypass via zsh regex conditionals
A Bash tool permission-check bypass vulnerability, where zsh could execute hidden commands in `[[ ]]` regex conditionals, has been fixed. Affected commands will now prompt for permission.
https://github.com/anthropics/claude-code/releases/tag/v2.1.221
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