Random hexadecimal characters in chat input

[Taanviir]

Description

Not sure how this happened, I just opened opencode in a tmux window and this happened. Additional context: I have a tmux shortcut to open opencode from a directory in a new window ( + o)

Plugins

None

OpenCode version

1.2.18 when I opened it

Steps to reproduce

I'm really sorry, I have no idea how this can be reproduced, I just started the application and it happened.

Screenshot and/or share link

Operating System

Windows 11, used the TUI in WSL

Terminal

Windows Terminal

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• OpenCode encounters automatically growing unreadable characters #16507: Similar issue with automatically growing unreadable/garbled characters in the TUI (SGR mouse mode sequences leaking)
• Random Artifactts In Terminal After Running #5936: Random artifacts appearing in terminal, also on Windows, tied to mouse movement after exiting opencode

If your issue is the same, please consider adding your context there instead.

[mechamogeo]

I’m seeing similar behavior in Ghostty on macOS using the fish shell. The random characters/artifacts appear when I scroll or when something is printed to the terminal (for example, when OpenCode initializes). No plugins enabled.

Environment:

• macOS 26.3
• Ghostty 1.2.3 stable
• Shell: fish 4.4.0
• Node: v24.13.0
• OpenCode: 1.2.20

Let me know if there are any specific logs or checks that would help.