[BUG] Code tab: fixed-framerate text rendering causes blank screen and unnecessary resource usage — should be event-driven

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The Code tab in claude.ai renders terminal output using a fixed-framerate loop (likely requestAnimationFrame or a setInterval-based polling mechanism) instead of event-driven DOM updates. This causes two problems:

1. Blank/frozen screen on load — The Code tab opens but never renders any content. No spinner, no cursor, nothing. The CLI version (claude in terminal) works perfectly at the same time, confirming the backend/API is functional. Refreshing sometimes fixes it, sometimes doesn't.

1. Unnecessary resource consumption — A polling-based renderer keeps burning CPU cycles even when idle (no input, no output). For a terminal emulator that receives discrete events (WebSocket messages, keystrokes), this is architecturally wasteful.

What Should Happen?

Event-driven rendering: WebSocket message arrives → DOM update triggers. No message → no render cycle. This would be both more efficient and more reliable, eliminating the blank-screen failure mode where the render loop loses sync with the underlying state.

Error Messages/Logs

Steps to Reproduce

1. Open claude.ai
2. Switch to the Code tab
3. Type anything (e.g. "ey")
4. Observe: message appears in input but no response rendering occurs — screen stays blank

<img width="899" height="746" alt="Image" src="https://github.com/user-attachments/assets/8eb0ec6f-c054-45e0-b491-935372aef114" />

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

Platform: claude.ai Code tab (interface, not CLI)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

The CLI version uses Ink (React for terminals) which is inherently event-driven. The browser wrapper appears to add a framerate-based rendering layer on top, which introduces a failure mode that doesn't exist in the CLI. Switching to event-driven updates (WS message → render) would align the browser implementation with the CLI's architecture and eliminate this class of bugs entirely.

Environment

• OS: Windows (also observed blank screen on other platforms per related issues)
• Browser: Chrome (latest)
• Claude Plan: Pro
• CLI works: Yes — claude in terminal runs fine
• Chat tab works: Yes — only Code tab affected

Related Issues

• #21764 (Code tab shows black screen on Windows)
• #25136 (Cowork tab not showing)