tl;dr: Hell froze over. Anthropic fixed Claude Code’s signature flicker in their latest update (2.0.72)
If there’s one thing everybody noticed about Claude Code (apart from it revolutionizing how we build software), it’s the flickering. It’s unfair to point to Anthropic since they are not alone: other TUIs such as Cursor, or really anything based on Ink have the same issue. It’s also not an easy problem at all. Claude Code uses React under the hood.1
The Issue
Terminals haven’t really been designed for interactivity. It’s possible to use ANSI escape codes to reposition the cursor and write over existing text, but that easily leads to flickering if not done well.
There are two ways to solve this:
Switch to alt mode and take complete control over the terminal viewport. Carefully re-render changed parts while leaving the scrollback unchanged.
Neither option is great, and each comes with tradeoffs. Mario Zechner explains these really well in his write-up on building pi-coding-agent, so I won’t repeat the details here. I’ve spent time with option 2 myself, having ported pi-tui to Swift as TauTUI (Codex did most of the auto-translation).
For a coding agent that mostly emits text with limited interactivity, I believe carefully re-rendering only changed parts — while remaining a good terminal citizen — is the better approach.
Anthropic seems to agree. Ink, the React-based terminal renderer Claude Code originally used, didn’t support the kind of fine-grained incremental updates needed for a long-running interactive UI. This has since improved upstream, but Anthropic needed tighter control, so they rewrote the renderer from scratch — while still keeping React as the component model.
This is kind of like if a website were to do their own text rendering, highlighting, mouse movement, context menu, etc. — it would not feel like your browser. (…) We value this native experience a lot. We may explore alternate screen mode in the future, but our bar is quite high. — Thariq, Anthropic
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