Claude Chill: Fix Claude Code's flickering in terminal

Original Article ↗ Hacker News Discussion ↗

Community reaction to Claude Chill

  • Many commenters are relieved and grateful; some call it the most useful contribution to Claude Code in months.
  • Several describe the flicker as literally headache‑inducing or hypnotic, making the tool unpleasant or unusable.
  • A few note side effects: the PTY proxy approach can break native terminal scrollback (e.g., in Ghostty), forcing a trade‑off between smoothness and scrollback.

Frustration with Claude Code flickering

  • Numerous users are incredulous the bug has persisted for months in a flagship “agentic coding” product.
  • Some say they would be embarrassed to ship a TUI that repeatedly clears and redraws the screen and scrollback.
  • Comparisons are made to other tools (Codex, opencode, Neovim, etc.) that “just work” without flicker, though a few note flickering in other React-based CLIs too.

Speculation on Anthropic’s engineering and process

  • Commenters mock the disconnect between lofty AI claims (“90% of code written by AI”) and failure to fix a basic terminal bug.
  • There’s speculation that Claude Code is partially or heavily AI-written and that dogfooding it may be slowing real fixes.
  • Some blame management/under‑resourcing rather than individual engineers; others say a commercial product at this scale no longer deserves “leeway.”

Technical causes and approaches

  • Original implementation used Ink (React TUI renderer) which clears and redraws on each update; later they replaced it with a custom React-based renderer.
  • Core issue: Claude Code uses scrollback rather than the alternate screen buffer, so it must clear and redraw scrollback, causing tearing/flicker.
  • A Claude Code engineer explains they shipped a new differential renderer, reducing flicker and adding support for synchronized output (DEC mode 2026) via patches to VS Code’s terminal and tmux.
  • They describe the TUI as “small game engine”-like, with a React scene graph → layout → rasterization → diff → ANSI pipeline, heavily optimized to avoid GC pauses.

Workarounds, alternatives, and feature wishes

  • Users mention Ghostty (with DEC 2026), tmux, zellij, and other tools; some still see bad flicker in tmux even on the latest version.
  • Alternatives like Rust/Go TUIs (ratatui, Bubbletea) are praised as smoother than the JS/React stack.
  • Requests include a toggle to keep input pinned to the bottom and clearer decoupling of the UI so other front‑ends can be built.