[Release] anthropics/claude-code v2.1.211: v2.1.211

Claude Code v2.1.211 is a maintenance release focused on bug fixes, security hardening, and performance improvements. Key updates include new subagent text forwarding options, fixes for permission preview character sanitization, auto mode hook decision handling, and credential store synchronization issues. The release also addresses file upload validation, terminal performance, background session management, and cross-platform compatibility issues across Claude in Chrome, VSCode, and various LLM backends (Vertex, Bedrock, Mantle, Foundry).

Key Points

• •Added `--forward-subagent-text` flag and `CLAUDE_CODE_FORWARD_SUBAGENT_TEXT` environment variable to include subagent text and thinking in stream-json output
• •Fixed security vulnerability: permission previews now neutralize bidirectional-override, zero-width, and look-alike quote characters to prevent visual alteration of approval messages
• •Fixed auto mode incorrectly overriding PreToolUse hook's `ask` decision for unsandboxed Bash — hook `ask` now takes precedence
• •Resolved parallel Claude Code sessions logging out simultaneously after wake-from-sleep when sharing credential stores
• •Fixed MCP server reconnection failures after idle web sessions wake, preventing MCP call failures
• •Fixed subagents with explicit model overrides reverting to parent's model when resumed or receiving follow-up messages
• •Improved file upload validation: DOS device suffixes (`.prn`) and trailing dots now accepted; files with multiple hard links refused
• •Fixed background agent result reporting to show status of still-running agents and wait for real completion instead of fabricating results
• •Updated integer environment variables to accept scientific notation and digit-separator spellings (e.g., `1e6`, `64_000`)
• •Fixed prompt-caching regression on Bedrock, Vertex, Mantle, and Foundry that incorrectly billed trailing system context blocks as fresh input tokens

Workflow Diagram

Concepts

Artifacts (2)

# New environment variable for subagent text forwarding
CLAUDE_CODE_FORWARD_SUBAGENT_TEXT=true

# Integer environment variables now support scientific notation and digit separators
TIMEOUT=1e6
TOKEN_BUDGET=64_000
RETRY_COUNT=1e2

# New flag for forwarding subagent text and thinking in stream-json output
claude-code --forward-subagent-text

# Existing commands with improved behavior
claude agents          # Improved background agent result reporting
/clear                 # Now resets session cost counter to $0
/usage-credits         # Now asks for confirmation before sending request
/terminal-setup        # Fixed screen reader audible terminal bell
/loop                  # Fixed session visibility in /resume
/resume                # Now shows all sessions including those from /loop