Interactive mode crashes with "zsh: suspended (signal)" on macOS 26.2

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?

Environment

• macOS: 26.2 (Build 25C56)
• Claude Code: 2.1.29 (also tested 2.1.17)
• Node.js: Tested v18.20.8 and v20.19.0
• Terminals: Warp, Terminal.app (both crash)
• Shell: zsh

Description

Interactive mode crashes with zsh: suspended (signal) within seconds of launching. The UI renders duplicate frames before crashing. Non-interactive mode (--print) works fine.

Steps to Reproduce

1. Fresh install: curl -fsSL https://claude.ai/install.sh | bash
2. Run claude
3. Type anything
4. Observe duplicate rendering and crash

Debug Info

• Debug log shows: High write ratio: blit=0, write=1617 (100.0% writes)
• System logs show excessive nw_path_libinfo_path_check network calls
• Crash occurs regardless of terminal width
• Crash occurs with TERM=dumb
• claude --print "hello" works correctly

What I've Tried

• Fresh install (wiped ~/.claude, ~/.claude.json, all backups)
• Multiple Claude Code versions (2.1.17, 2.1.29)
• Multiple Node versions (18, 20)
• Multiple terminals (Warp, Terminal.app)
• Wider terminal window
• TERM=dumb
• Removed all MCP servers

Workaround

claude --print mode works, only interactive mode is broken.

What Should Happen?

Claude Code should launch and stay responsive without crashing. The UI should render cleanly without duplicate frames.

Error Messages/Logs

Steps to Reproduce

1. Install Claude Code: curl -fsSL https://claude.ai/install.sh | bash
2. Run claude in any terminal
3. Type any text and press Enter
4. Observe: UI duplicates frames multiple times, then crashes with "zsh: suspended (signal)"

Claude Model

Opus

Is this a regression?

No, this never worked

Last Working Version

_No response_

Claude Code Version

2.1.29

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Warp

Additional Information

The --print flag works correctly, only interactive mode is broken. This suggests the issue is in the terminal UI renderer (Ink/React), not the API connection.