Copy-on-Select fails when running opencode via Tmux in Kitty terminal (Linux)

[geofarmbuilder]

Description

When using the opencode CLI tool on a remote Linux server within a tmux session inside the Kitty terminal emulator, the "auto-copy on select" functionality fails. Highlighting text does not populate the system clipboard.

Note: This functionality works as expected in the same environment when using other CLI tools like claude-code or codex, suggesting the issue is specific to how opencode handles terminal escape sequences or clipboard integration.

Environment
Local OS: macOS

Terminal Emulator: Kitty

Remote OS: Ubuntu 24.04

Terminal Multiplexer: tmux 3.4-1ubuntu0.1

Connection: SSH

OpenCode Version:

Steps to Reproduce
Connect to a remote Linux server via SSH using the Kitty terminal.

Start a tmux session.

Launch opencode.

Select/highlight text within the opencode interface.

Attempt to paste the selection into a local application.

Expected Behavior
The selected text should be automatically copied to the system clipboard consistent with the behavior of claude-code or codex.

Actual Behavior
The text is highlighted, but the clipboard remains unchanged. No data is passed back to the local client.

Plugins

No response

OpenCode version

No response

Steps to reproduce

No response

Screenshot and/or share link

No response

Operating System

No response

Terminal

No response

[github-actions]

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

• Windows & Ubuntu: impossible to paste API key after /connect (Ctrl-V / Ctrl-Shift-V / right-click all fail, no hints) #9922: Windows & Ubuntu: impossible to paste API key after /connect (Ctrl-V / Ctrl-Shift-V / right-click all fail, no hints) - Related to clipboard/paste functionality failures in terminal environments
• Can't open TUI running on a remote Omnissa Horizon machine #9903: Can't open TUI running on a remote Omnissa Horizon machine - Mentions Kitty terminal issues on remote machines and tmux with similar terminal rendering problems

Feel free to ignore if none of these address your specific case.

[stonematt]

I can confirm this is also happening in Ghostty with tmux on Mac on local files. Here's the observed behavior:

without tmux

1. open Ghostty -> opencode
2. start a session, get a response
3. highlight text -> see banner pop up that says "Copied to Clipboard"
4. Paste - WORKS!

with tmux

1. open Ghostty -> start tmux -> opencode
2. start a session, get a response
3. highlight text -> see banner pop up that says "Copied to Clipboard"
4. Paste - NOT THE COPIED TEXT - FAIL!

this worked until a few days ago. This feels like a regression.

➜ opencode --version
1.1.49

Here's my tmux.conf (nothing too special):

# Enable mouse control (clickable windows, panes, resizable panes)
set -g mouse on

# Set history limit
set -g history-limit 50000

# for neovim
set -sg escape-time 10

# Key bindings to for intuitive splits
bind | split-window -hc "#{pane_current_path}"
bind - split-window -vc "#{pane_current_path}"

# Improve window navigation
bind-key -n C-Left  previous-window
bind-key -n C-Right next-window
# Enable vim-style pane navigation
bind-key -n C-h select-pane -L
bind-key -n C-l select-pane -R
bind-key -n C-j select-pane -D
bind-key -n C-k select-pane -U

# Resize panes without prefix using Ctrl+Shift+Arrow keys
bind-key -n C-S-Up resize-pane -U 5
bind-key -n C-S-Down resize-pane -D 5
bind-key -n C-S-Left resize-pane -L 5
bind-key -n C-S-Right resize-pane -R 5


# Enable vi mode for copy mode
setw -g mode-keys vi

# Set default terminal
set -g default-terminal "screen-256color"

# status bar
set -g status-right "#(pomo)"
set -g status-style "fg=#665c54"
set -g status-left-style "fg=#928374"

set -g status-bg default
set -g status-position top
set -g status-interval 1
set -g status-left ""

# disable status
# set -g status off
# set -g status on

# count the panes from 1
set -g base-index 1
setw -g pane-base-index 1

# reload configuration
bind-key -r r source-file ~/.tmux.conf

# Plugin manager
set-environment -g TMUX_PLUGIN_MANAGER_PATH ~/.tmux/plugins/

# List of plugins
set -g @plugin 'tmux-plugins/tpm'
set -g @plugin 'tmux-plugins/tmux-sensible'
set -g @plugin 'christoomey/vim-tmux-navigator'

# Other examples:
# set -g @plugin 'github_username/plugin_name'
# set -g @plugin 'github_username/plugin_name#branch'
# set -g @plugin 'git@github.com:user/plugin'
# set -g @plugin 'git@bitbucket.com:user/plugin'

# Initialize TMUX plugin manager
run-shell '~/.tmux/plugins/tpm/tpm'