CLI rendering: chat panel becomes unreadable / Unicode-mangled mid-session
What happened
During an active Claude Code session, the chat panel text rendered into garbled / unreadable characters (looks like a Unicode or terminal-redraw glitch). The session was still responsive — the model continued processing tool calls and responses — but every line in the chat panel was visually corrupted to the point of being unreadable. Scrolling did not recover. A screenshot is available; happy to attach via comment.
Environment
- Claude Code version: 2.1.143
- OS: macOS 26.1 (build 25B78), Darwin 25.1.0
- Terminal: VS Code integrated terminal (
TERM_PROGRAM=vscode) - Shell: zsh
- Model: Opus 4.7 (1M context)
Session characteristics when it broke
- Long-running session (several hours)
- Many tool calls of mixed types: Bash, Read, Write, Edit, MCP browser (Playwright), MCP Linear, MCP Supabase, MCP Railway
- Mixed-content rendering throughout — long curl bodies, base64/binary-ish output from git, image reads, JSON blobs
- Conversation included foreign characters (Bahasa Malaysia text in commit messages, em-dashes, Unicode arrows)
- Frequent ANSI-color output from CLI tools (railway logs, gh, vercel)
Steps to reproduce
Not deterministic. Triggers seem to involve a long session with heavy mixed-encoding output (binary blobs, ANSI escapes, multibyte strings) all flowing through the chat panel. Eventually the terminal renderer drops into the broken state.
Expected
Chat panel text continues to render normally even after long sessions / mixed-encoding content.
Actual
Chat panel becomes unreadable mid-session — see attached screenshot.
Workarounds attempted
To be confirmed by reporter:
- \
clear\and resize the terminal window (forces redraw) - Detach and reattach the session
- Switch terminals (VS Code integrated → Terminal.app / iTerm2)
Notes
- Same issue may correlate with the VS Code integrated terminal specifically (\
TERM_PROGRAM=vscode\); we haven't reproduced in a standalone terminal yet. - The model side is fine — only the rendering layer is affected.
7 Comments
Found 3 possible duplicate issues:
This issue will be automatically closed as a duplicate in 3 days.
🤖 Generated with Claude Code
Same issue for me
<img width="1140" height="424" alt="Image" src="https://github.com/user-attachments/assets/2710b24b-cf0a-4354-a0b9-e6338cedbb6e" />
Same here. Version 2.1.143 on macos
<img width="886" height="231" alt="Image" src="https://github.com/user-attachments/assets/0d572c31-3732-49ca-b27e-8f1f005845fb" />
Same here on Claude Code 2.1.144, macOS Sequoia 15.7.3
<img width="1006" height="623" alt="Image" src="https://github.com/user-attachments/assets/d2ae32e8-fe81-4845-9ae5-a035e50457de" />
Adding a data point — same symptom on a different platform, which suggests this isn't macOS-specific.
Environment
TERM_PROGRAM=vscode,VSCODE_INJECTION=1,TERM=xterm-256color,COLORTERM=truecolor)Notes
TERM_PROGRAM=vscodecorrelation — same renderer break across macOS 26.1 and WSL2/Linux, common factor is the VS Code integrated terminal.gh/docker, multibyte chars in commit messages and docs). Consistent with the trigger pattern in the original report.Happy to attach a screenshot if useful.
Same here.
MacOS: Tahoe 26.3
VS Code: 1.121.0
Ghostty: 1.3.1
Claude Code: 2.1.150
<img width="956" height="536" alt="Image" src="https://github.com/user-attachments/assets/c89b1137-0e53-4b52-a54d-e95be2625ad8" />
This issue has been automatically locked since it was closed and has not had any activity for 7 days. If you're experiencing a similar issue, please file a new issue and reference this one if it's relevant.