[BUG] OSC terminal color query responses leak into input buffer

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?

Random strings appear in the input box while Claude is responding:
]11;rgb:1414/1414/1414]11;rgb:1414/1414/1414]10;rgb:e4e4/e4e4/e4e4\

These are OSC escape sequence responses:

• ]11;rgb:... - terminal background color response
• ]10;rgb:... - terminal foreground color response

Once that happens once, when I scroll up it scrolls through input prompts rather than through my chat history. In Ghostty, I can still do shift+scroll to scroll up properly.

What Should Happen?

Color query responses should be captured/suppressed, not appear in user input.

Error Messages/Logs

Steps to Reproduce

Environment:

• Claude Code version: 2.0.56 (native install)
• OS: macOS (26.1)
• Affected terminals: Terminal.app, Ghostty, Cursor integrated terminal

Relevant shell config (~/.zshrc):

  # Using zsh with:
  eval "$(/opt/homebrew/bin/brew shellenv)"
  eval "$(pyenv init -)"
  eval "$(zoxide init zsh)"

  # Starship disabled during debugging (issue persists without it)
  # eval "$(starship init zsh)"

  # zsh plugins
  source /opt/homebrew/share/zsh-syntax-highlighting/zsh-syntax-highlighting.zsh
  source /opt/homebrew/share/zsh-autosuggestions/zsh-autosuggestions.zsh
  source ~/.fzf.zsh

claude doctor output:
Diagnostics
└ Currently running: native (2.0.56)
└ Path: /Users/austin/.local/bin/claude
└ Invoked: /Users/austin/.local/share/claude/versions/2.0.56
└ Config install method: native
└ Auto-updates: default (true)
└ Search: OK (bundled)

Occurs when resuming longer Claude some sessions, and in the middle of Claude responses. My guess is when a certain colour/process happens that doesn't always happen with short sessions.

Claude Model

Not sure / Multiple models

Is this a regression?

Yes, this worked in a previous version

Last Working Version

(worked last week, but unknown if it was a regression in Claude Code or a change in my environment)

Claude Code Version

2.0.56 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS) + Ghostty + Cursor

Additional Information

Could be a change in my environment, but I think it's still a bug in Claude Code as e.g. Codex and other CLI tools have not been affected.

https://github.com/user-attachments/assets/23fb2a85-56bd-4a3f-9d6d-00a639f450ef