[FEATURE]: tui: expose border style (rounded corners) for dialogs and panels #57149

• I have verified this feature I'm about to request hasn't been suggested before.

(#42659 asked for the same thing on v1 and was auto-closed for inactivity. The behaviour on v2 is different, so I'm filing it again with the details below.)

Describe the enhancement you want to request

I'd like the border style used by the TUI to be configurable, so frames can be drawn with rounded corners (╭ ╮ ╰ ╯) instead of square ones (┌ ┐ └ ┘).

The reason is that I'm putting together a custom theme, and right now the corners are square in almost every panel while the Error and Stack trace dialogs already use rounded ones. The result is an inconsistent UI that can't be made consistent in either direction, since there's no setting to change it.

What I'd change

The renderer already supports this, so as far as I can tell it would be a matter of exposing an existing option rather than implementing new rendering.

OpenTUI's box renderable takes a borderStyle prop with four values:

var ls = ["single", "double", "rounded", "heavy"]

rounded uses U+256D–U+2570 (╭ ╮ ╰ ╯), and the default for box is single.

OpenCode already uses two of those values, hardcoded per component:

• the Error dialog → rounded
• the Stack trace dialog → rounded
• the prompt/composer box → heavy, with rounded caps (╹ ╸ ╺ ╻)

So the rounded corner characters are already in the shipped binary, and the Error dialog does already draw with rounded corners. The only thing missing is a way to choose the style:

• the theme format carries colours only — the border group has a single base entry, with nothing about the style or the corners
• cli.json has no equivalent setting
• a plugin can't change it either, since plugins don't control how the built-in components are drawn

There's one more detail worth mentioning: the main dialogs (command palette, settings, model picker) are currently drawn with no border at all — they're a flat surface("dialog").background.base rectangle over a rgba(0,0,0,150) scrim — so there are no corners to round there yet. It would be nice if they got a border, so the selected style is actually visible on them.

What I think this would bring

• a consistent look across the TUI, instead of the current mix of square and rounded frames
• the option to pick rounded (or double, or heavy) for anyone who wants it
• themes would be able to express more than just colour

How I'd expose it

Either of these would do it for me:

• a border.style entry in the theme format, accepting "single" | "double" | "rounded" | "heavy"
• a setting in cli.json such as tui.border_style

Defaulting to the current behaviour, so existing setups stay as they are.

Environment

• opencode version: 2.0.32 (channel: latest)
• OS: Linux 7.2.11-200.fc44.x86_64 (Fedora 44), x86_64
• Terminal: kitty (theme "Hachiko") on KDE Plasma, COLORTERM=truecolor
• Shell: /bin/bash
• Active plugins: none

Related

• [FEATURE]: Rounded corners for TUI code blocks and input box #42659 — "Rounded corners for TUI code blocks and input box", on v1. Closed automatically for inactivity rather than declined. It noted that the rounded variants "are not present in the binary at all", which is no longer the case in v2, and the renderer support it assumed but didn't verify does exist.
• Session panel bottom corners render square in v2 layout #31439 — "Session panel bottom corners render square in v2 layout", concerned the v1 layout.