[FEATURE]: Toggle to disable mouse tracking in the TUI #36266

Problem

There is no way to toggle mouse tracking in the OpenCode TUI from inside the session. When running OpenCode on a remote machine over SSH from the macOS Terminal app, this makes it impossible to copy text from the TUI reliably.

Repro

1. SSH into a remote host (e.g. ssh user@host).
2. Run opencode on the remote host.
3. Try to select text with the mouse and copy it.
4. Expected: the selected text lands in the local macOS clipboard.
5. Actual: text is not copied. Cmd+C is intercepted by the TUI and does nothing useful. Mouse selection is captured by the TUI itself, so it never reaches the terminal's native selection buffer either.

Why this happens

OpenCode's TUI captures mouse input by default (enableMouse() in the renderer setup). On selection it tries to write to the clipboard via OSC52 (console.onCopySelection).

That only works when the local terminal actually implements OSC52. macOS Terminal.app only gained OSC52 support in macOS Sonoma 14.4 / Terminal 2.13. On older Terminal.app, on remote SSH sessions where OSC52 is filtered or unsupported by the mux, or when running inside tmux/screen without set-clipboard on, the selection silently disappears into the TUI and the user has no way to copy.

The existing escape hatch is OPENCODE_EXPERIMENTAL_DISABLE_COPY_ON_SELECT=1, but it only disables the intercept("key", ...) handler. It does not disable mouse tracking, so the TUI still captures mouse drag selections and the text still does not reach the terminal's native selection buffer.

Proposed solution

Expose a user-facing toggle to disable mouse tracking in the TUI. Either of these would solve the problem:

• A /mouse slash command that toggles mouse capture on/off.
• A configurable hotkey for the same.
• An opt-in config field under tui (e.g. tui.mouse = false or tui.mouse_tracking = false) that defaults to current behavior but can be turned off.

When mouse tracking is off, the user gets normal terminal mouse selection and can copy via Cmd+C / Shift+drag / the terminal's own copy mechanism, regardless of OSC52 support.

For reference, hermes-agent already ships a /mouse toggle for exactly this use case and it works well there.

Environment

• opencode 1.17.15
• macOS Terminal.app (no third-party terminal)
• Connected over SSH to a remote Linux host
• OPENCODE_EXPERIMENTAL_DISABLE_COPY_ON_SELECT=1 does not help (see above)