Claude Code sends extensive terminal updates wrapped in sync markers, leading to performance issues like lag and flicker. When it redraws the entire terminal screen, it can send thousands of lines at once, even if only a fraction are visible. This behavior significantly hampers user experience, as terminals struggle to handle such large updates smoothly. claude-chill acts as a PTY proxy to solve this problem. It intercepts these large atomic updates and employs VT-based rendering to only display the differences, reducing flicker and improving responsiveness. The tool also maintains a history buffer, allowing users to pause and review previous outputs. You can install it via Cargo or Nix, and it includes several customization options such as setting the maximum lines for history and defining a lookback key. The setup is straightforward. You run claude-chill followed by the command you want to execute. It provides flexibility in managing how much history to store and how to trigger lookback mode. For instance, you can set the lookback key to a function key or disable auto-lookback. On macOS, some terminals may require a different key combination due to how they handle control characters. While claude-chill is designed for personal use and has been tested primarily on Linux and macOS, it may not perform equally well across all terminal types. The developer warns against using it in critical applications due to its untested nature in edge cases.