Claude Code 2.1.88: Flicker-Free Rendering, Cache Fixes

TL;DR

• Flicker-free alt-screen rendering now available via environment variable
• Fixed critical prompt cache misses and nested CLAUDE.md re-injection in long sessions
• Resolved StructuredOutput schema cache bug causing ~50% workflow failures
• Fixed memory leaks, crashes on large files, and voice mode issues across platforms

New

• Flicker-free rendering — Set CLAUDE_CODE_NO_FLICKER=1 to enable virtualized scrollback with alt-screen rendering, eliminating visual flicker in long sessions.
• PermissionDenied hook — New hook fires after auto mode classifier denials; return {retry: true} to let the model retry denied commands.
• Named subagents in typeahead — Subagents now appear in @ mention suggestions for easier discovery.

Fixed

• Prompt cache misses in long sessions — Tool schema bytes no longer change mid-session, preventing cache invalidation.
• Nested CLAUDE.md re-injection — Files are no longer re-injected dozens of times when reading many files in extended sessions.
• StructuredOutput schema cache bug — Fixed ~50% failure rate in workflows using multiple schemas.
• CRLF doubling on Windows — Edit/Write tools no longer double CRLF or strip Markdown hard line breaks (two trailing spaces).
• Memory leak in long sessions — Large JSON inputs no longer retained as LRU cache keys.
• Out-of-memory crash on large files — Edit tool now handles files over 1 GiB without crashing.
• Crash on large session files — Message removal from files over 50MB now works reliably.
• --resume crash — Fixed crash when transcript contains tool results from older CLI versions or interrupted writes.
• Misleading rate limit errors — API entitlement errors now show actual error with actionable hints instead of generic "Rate limit reached" message.
• LSP server zombie state — Server now restarts on next request after crash instead of failing until session restart.
• Hook condition filtering — if conditions now match compound commands (ls && git push) and env-var prefixes (FOO=bar git push).
• CJK/emoji in prompt history — Entries with CJK or emoji no longer silently dropped at 4KB boundaries in ~/.claude/history.jsonl.
• /stats data loss — Historical data beyond 30 days now preserved when cache format changes.
• /stats token undercounting — Now includes subagent and fork usage in token counts.
• Scrollback disappearing — Scrolling up in long sessions no longer loses content.
• Collapsed badge duplication — Search/read group badges no longer duplicate during heavy parallel tool use.
• Notification invalidation — invalidates now clears currently-displayed notifications immediately.
• Prompt flashing after submit — Prompt no longer briefly disappears when background messages arrive during processing.
• Long /btw responses clipped — Responses now render in scrollable viewport instead of being cut off.
• Devanagari text truncation — Combining-mark text no longer truncated in assistant output.
• Terminal rendering artifacts — Layout shifts no longer cause visual artifacts on main-screen terminals.
• Voice mode microphone permission on macOS — Apple Silicon now correctly requests microphone permission.
• Voice push-to-talk activation — Some modifier-combo bindings now work correctly.
• Voice mode WebSocket error on Windows — Fixed "WebSocket upgrade rejected with HTTP 101" error.
• Shift+Enter on Windows Terminal Preview — Now inserts newline instead of submitting on version 1.25+.
• UI jitter in iTerm2 + tmux — Periodic jitter during streaming now eliminated.
• PowerShell stderr reporting — Commands like git push writing to stderr no longer incorrectly reported as failures on Windows PowerShell 5.1.
• SDK error result messages — error_during_execution and error_max_turns now correctly set is_error: true with descriptive messages.
• Task notifications lost on Ctrl+B — Backgrounding a session no longer loses notifications.
• Hook file_path not absolute — PreToolUse/PostToolUse hooks now provide absolute paths for Write/Edit/Read tools.

Improved

• PowerShell tool prompt — Now includes version-appropriate syntax guidance for 5.1 vs 7+.
• Thinking summaries disabled by default — No longer generated in interactive sessions; set showThinkingSummaries: true in settings to restore.
• Auto mode denials visibility — Denied commands now show notification and appear in /permissions → Recent tab.
• /env scope expanded — Now applies to PowerShell tool commands (previously Bash only).
• /usage plan display — Hides redundant "Current week (Sonnet only)" bar for Pro and Enterprise plans.
• Collapsed tool summary — Now shows "Listed N directories" for ls/tree/du instead of "Read N files".
• Image paste behavior — No longer inserts trailing space.
• Bash mode entry — Pasting !command into empty prompt now enters bash mode, matching typed ! behavior.

Update Claude Code: brew upgrade claude-code or download from code.claude.com.

Source: Claude Code