[FEATURE]: Add tui.json option to control content area max-width / horizontal padding

Description

After a recent upgrade, the horizontal margins/padding on the main content area in the TUI appear to have increased, making the readable content area noticeably narrower — especially on wide terminals. Tables and long-form output get compressed while there's unused space on either side.

This was previously raised in #838, which was closed without a user-facing config option being added.

Request

Add a tui.json option (e.g. content_max_width or content_padding) that lets users control how wide the main response content area renders. Something like:

// tui.json
{
  "content_max_width": 0, // 0 = full terminal width
  "content_padding": 1    // horizontal padding in columns
}

Currently tui.json supports scroll_speed, diff_style, mouse, etc. — but nothing for layout/spacing of the content area.

Current behavior

Content area has fixed left/right margins that cannot be overridden
The theme system only controls colors, fonts, and syntax highlighting — not layout
No documented workaround exists for adjusting content width

Expected behavior

Users can configure the content area width through tui.json
Sensible default preserved, but overridable for users with wide terminals

Environment

OS: macOS
Terminal: wide-screen setup

Draft PR with a minimal implementation: #25146

Adds a content_padding option to tui.json (integer, 0–20, default 2) that controls the horizontal padding on the main session content area. Two files changed, backward-compatible — existing behavior is preserved unless the user opts in.

All CI checks are passing.

Updated PR with proper template (previous one was auto-closed for not following the PR template): #25171

All CI checks passing including compliance.

I am using desktop open code on Mac and my problem is that the code diff is always stacked, even when there's wide enough space to show them side by side. I hate this stacked view, but I could not find any option that allow me to change it.

feat(tui): add content_padding option to control horizontal content m…

Thanks for tracking this — I ran into the same wasted-space problem on wide terminals and did a bit of source reading before finding this issue. Sharing what I found in case it helps scope the implementation; happy to open a PR if useful.

In packages/tui/src/routes/session/index.tsx, the effective content width is driven by two hardcoded values:

// index.tsx:265
const wide = createMemo(() => dimensions().width > 120)
// index.tsx:273
const contentWidth = createMemo(() => dimensions().width - (sidebarVisible() ? 42 : 0) - 4)

So on a wide terminal the sidebar auto-shows at width > 120 and consumes 42 columns, and there's a fixed - 4 (the paddingLeft/Right={2} on the message container at index.tsx:1168-1169). Messages themselves have no maxWidth — they fill contentWidth.

A couple of things that look like good news for implementation:

There's already a precedent for a width cap in the TUI config: prompt.max_width (a positive int or "auto") in packages/tui/src/config/index.tsx:48, consumed in routes/home.tsx:33-37. A content_max_width with the same shape would be consistent.
The main-config layout ("auto" | "stretch") is already @deprecated and forced to stretch (per https://opencode.ai/config.json), so the stretch behavior is settled and a width cap would layer on top cleanly.

My read is that #6087 (sidebar width) and #20230 (padding) are the other two levers on the same contentWidth line, so the three issues could plausibly be addressed together with a small tui.json surface (e.g. content_max_width, sidebar_width, content_padding). But I'll defer to whoever picks this up on whether to do them in one pass or separately.

If a PR is welcome, I'd suggest starting with content_max_width (smallest, matches the existing prompt.max_width pattern). Let me know and I can put it up.

Following up with the desktop app (packages/app) side of this, since the wasted-space problem shows up there too and the root cause is a separate code path from the TUI.

In the desktop app the session message timeline is hard-capped and centered:

packages/app/src/pages/session/timeline/message-timeline.tsx:1013-1015

"min-w-0 w-full max-w-full": true,
"md:max-w-200 2xl:max-w-[1000px]": props.centered,   // cap at ~800px / 1000px
"md:mx-auto": props.centered,                          // center, leaving empty sides

The centered flag comes from packages/app/src/pages/session.tsx:181:

const centered = createMemo(() => isDesktop() && !desktopReviewOpen())

So on a wide desktop window with the review panel closed, the message column is forced to max-w-200 (~800px) / 2xl:max-w-[1000px] and horizontally centered — which is exactly the "large empty margins on both sides" complaint. The composer mirrors the same logic (session-composer-region.tsx:228).

This looks like the desktop-app equivalent of the TUI content_max_width ask in this issue. A single content_max_width setting (0 / int / "auto") that both the TUI (packages/tui) and the desktop app (packages/app) honor would resolve it uniformly. On the desktop side the change would be to feed the setting into the centered memo / the max-w-* classes in message-timeline.tsx and session-composer-region.tsx.

Happy to take this on (both sides, or just the desktop side) if a PR is welcome.

I'll work on this. Plan: add an optional content_padding (horizontal padding in columns) option to tui.json, wired into the session content area with the current behavior as the default, following the existing config schema pattern.

@AliAltivate

@AliAltivate Any updates on this?

Thanks for the request! You're asking for a tui.json option to control the horizontal padding and/or maximum width of the main session content area, so wide terminals are used better.

In the current TUI the session view's side padding is fixed (2 columns per side, plus a small indent on each message part), and none of it can be set in tui.json yet. This isn't something a plugin can change, since plugins can't adjust the core session layout. The maintainers will consider it.

Related issues:

[FEATURE]: configurable TUI padding #20230: earlier request for configurable TUI padding through tui.json (closed as stale)
Better use of horizontal space in the session view on wide terminals #32995: better use of horizontal space on wide terminals (closed as a duplicate of this issue)
layout width. #838: the original report about the narrow layout width
[FEATURE]: Resizable session content width in Desktop/Web #53382: the same request for the Desktop/Web app
feat(tui): add sidebar width configuration option #35513: configurable sidebar width (the sidebar also takes up horizontal space on wide terminals)

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[FEATURE]: Add tui.json option to control content area max-width / horizontal padding #25142

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[FEATURE]: Add tui.json option to control content area max-width / horizontal padding #25142

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alohaninja commented on Apr 30, 2026

alohaninja commented on Apr 30, 2026

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AliAltivate commented on Aug 12, 2026

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