Claude-Code v2.1.88: Flicker-Free Rendering & Permission Hooks

Claude-Code v2.1.88 Release Notes

Claude-Code v2.1.88 includes significant stability improvements, new hooks for workflow control, and fixes for terminal rendering issues that affected long-running sessions.

New Features and Environment Variables

Flicker-free rendering: Set CLAUDE_CODE_NO_FLICKER=1 to enable virtualized scrollback with alt-screen rendering.
PermissionDenied hook: Fires after auto mode classifier denials. Return {retry: true} to allow the model to retry the command.
Named subagents: Added to @ mention typeahead suggestions.

Critical Fixes

Memory and crash fixes: Fixed memory leak where large JSON inputs were retained as LRU cache keys. Fixed potential out-of-memory crash when Edit tool was used on files >1 GiB. Fixed crash when removing messages from session files over 50MB.
Session stability: Fixed prompt cache misses caused by tool schema bytes changing mid-session. Fixed nested CLAUDE.md files being re-injected dozens of times in long sessions.
Windows-specific fixes: Fixed Edit/Write tools doubling CRLF on Windows and stripping Markdown hard line breaks (two trailing spaces). Fixed voice mode on Windows failing with "WebSocket upgrade rejected with HTTP 101". Fixed Shift+Enter submitting instead of inserting newline on Windows Terminal Preview 1.25.
Terminal rendering: Fixed scrollback disappearing when scrolling up in long sessions. Fixed rendering artifacts on main-screen terminals after layout shifts. Fixed periodic UI jitter during streaming in iTerm2 when running inside tmux.
Data integrity: Fixed prompt history entries containing CJK or emoji being silently dropped at 4KB boundaries in ~/.claude/history.jsonl. Fixed /stats losing historical data beyond 30 days when cache format changes.

Tool and Hook Improvements

PowerShell tool: Improved prompt with version-appropriate syntax guidance (5.1 vs 7+). Fixed incorrect failure reporting when commands like git push wrote progress to stderr on Windows PowerShell 5.1. /env now applies to PowerShell commands (previously only affected Bash).
Hooks: Fixed hooks if condition filtering not matching compound commands (ls && git push) or commands with env-var prefixes (FOO=bar git push). Fixed PreToolUse/PostToolUse hooks not providing file_path as absolute path for Write/Edit/Read tools.
StructuredOutput: Fixed schema cache bug causing ~50% failure rate in workflows with multiple schemas.

Interface and Behavior Changes

Thinking summaries: No longer generated by default in interactive sessions. Set showThinkingSummaries: true in settings to restore.
Auto mode: Denied commands now show notification and appear in /permissions → Recent tab.
Collapsed tool summary: Now shows "Listed N directories" for ls/tree/du instead of "Read N files".
Image paste: No longer inserts trailing space.
Pasting behavior: Pasting !command into empty prompt now enters bash mode, matching typed ! behavior.

Additional Fixes

Fixed misleading "Rate limit reached" message when API returned entitlement error — now shows actual error with actionable hints.
Fixed LSP server zombie state after crash — server restarts on next request instead of failing until session restart.
Fixed collapsed search/read group badges duplicating in terminal scrollback during heavy parallel tool use.
Fixed notification invalidates not clearing currently-displayed notification immediately.
Fixed prompt briefly disappearing after submit when background messages arrived during processing.
Fixed long /btw responses being clipped — now render in scrollable viewport.
Fixed Devanagari and other combining-mark text being truncated in assistant output.
Fixed voice mode failing to request microphone permission on macOS Apple Silicon.
Fixed voice push-to-talk not activating for some modifier-combo bindings.
Fixed task notifications being lost when backgrounding session with Ctrl+B.
Fixed --resume crash when transcript contains tool result from older CLI version or interrupted write.
Fixed SDK error result messages (error_during_execution, error_max_turns) to correctly set is_error: true with descriptive messages.
/usage now hides redundant "Current week (Sonnet only)" bar for Pro and Enterprise plans.