[Release] anthropics/claude-code v2.1.217: v2.1.217

Claude Code v2.1.217 introduces emoji shortcode autocomplete, improves transcript reliability with failure warnings, and fixes critical issues including memory leaks, Windows auto-update failures, and security vulnerabilities in session isolation. The release also enhances subagent management with concurrency caps and nesting controls, while addressing telemetry routing, screen reader accessibility, and various edge cases in session handling and transcript management.

Key Points

• •Emoji shortcode autocomplete now available in prompt input (e.g., `:heart:` → ❤️) with toggle via `emojiCompletionEnabled` setting
• •Added warnings for transcript write failures (disk full) and disabled session saving instead of silently losing data
• •Fixed critical memory leak where truncated MCP tool outputs retained full untruncated results in memory for entire session
• •Resolved Windows auto-update failures that could delete `claude.exe`; failed updates now auto-restore preserved executable
• •Fixed background session isolation vulnerability where symlinked working directories allowed sessions to escape workspace folder
• •Auto-compact now triggers for Claude Opus 4.8 on Bedrock and `/compact` command works correctly at limits
• •Restored corporate security settings (mTLS, TLS-verify, OAuth scope, proxy) in Claude Desktop sessions
• •Improved screen reader accessibility by preventing startup announcement cutoff and reducing status row re-renders
• •Fixed telemetry routing where managed settings for `OTEL_EXPORTER_OTLP_ENDPOINT` now govern all signals consistently
• •Added concurrency cap on subagents (default 20, configurable via `CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS`) to prevent unbounded spawning

Workflow Diagram

Concepts

Artifacts (3)

# Default: 20 concurrent subagents
CLAUDE_CODE_MAX_CONCURRENT_SUBAGENTS=20

# Control nested subagent spawning depth
CLAUDE_CODE_MAX_SUBAGENT_SPAWN_DEPTH=1

{
  "emojiCompletionEnabled": true
}

# Force hyperlinks in footer PR badges even without terminal detection
# Set to 0 to opt out
FORCE_HYPERLINK=1