From e1581183ff93a014aed9660f3b42c703914b1130 Mon Sep 17 00:00:00 2001
From: Brendan Allan <14191578+Brendonovich@users.noreply.github.com>
Date: Wed, 27 May 2026 15:42:21 +0800
Subject: [PATCH] feat(app): allow toggling tabs layout (#29526)

---
 packages/app/src/app.tsx                      |  25 +-
 packages/app/src/components/prompt-input.tsx  |   6 +-
 .../src/components/session/session-header.tsx |  12 +-
 .../app/src/components/settings-general.tsx   |  14 +-
 packages/app/src/components/titlebar.tsx      |  12 +-
 packages/app/src/context/settings.tsx         |   6 +
 packages/app/src/i18n/en.ts                   |   2 +
 packages/app/src/pages/home.tsx               |  10 +-
 packages/app/src/pages/layout.tsx             | 320 +++++++++---------
 packages/app/src/pages/session.tsx            |   8 +-
 .../pages/session/new-session-layout.test.ts  |  12 +-
 .../src/pages/session/new-session-layout.ts   |   4 +-
 .../src/pages/session/session-side-panel.tsx  |   6 +-
 .../pages/session/use-session-commands.tsx    |   4 +-
 14 files changed, 235 insertions(+), 206 deletions(-)

diff --git a/packages/app/src/app.tsx b/packages/app/src/app.tsx
index c4eadbd5f..9554a6363 100644
--- a/packages/app/src/app.tsx
+++ b/packages/app/src/app.tsx
@@ -14,6 +14,7 @@ import { QueryClient, QueryClientProvider } from "@tanstack/solid-query"
 import { Effect } from "effect"
 import {
   type Component,
+  createEffect,
   createMemo,
   createResource,
   createSignal,
@@ -40,7 +41,7 @@ import { NotificationProvider } from "@/context/notification"
 import { PermissionProvider } from "@/context/permission"
 import { PromptProvider } from "@/context/prompt"
 import { ServerConnection, ServerProvider, serverName, useServer } from "@/context/server"
-import { SettingsProvider } from "@/context/settings"
+import { SettingsProvider, useSettings } from "@/context/settings"
 import { TerminalProvider } from "@/context/terminal"
 import DirectoryLayout from "@/pages/directory-layout"
 import Layout from "@/pages/layout"
@@ -48,11 +49,6 @@ import { ErrorPage } from "./pages/error"
 import { useCheckServerHealth } from "./utils/server-health"
 import { ServersProvider } from "./context/servers"
 
-if (import.meta.env.VITE_OPENCODE_CHANNEL !== "prod") {
-  document.body.classList.remove("text-12-regular")
-  document.body.classList.add("font-(family-name:--font-family-text)", "text-[13px]", "font-[440]")
-}
-
 const HomeRoute = lazy(() => import("@/pages/home"))
 const Session = lazy(() => import("@/pages/session"))
 
@@ -97,9 +93,26 @@ function QueryProvider(props: ParentProps) {
   return <QueryClientProvider client={client}>{props.children}</QueryClientProvider>
 }
 
+function BodyDesignClass() {
+  const settings = useSettings()
+
+  createEffect(() => {
+    if (typeof document === "undefined") return
+
+    const enabled = settings.general.newLayoutDesigns()
+    document.body.classList.toggle("text-12-regular", !enabled)
+    document.body.classList.toggle("font-(family-name:--font-family-text)", enabled)
+    document.body.classList.toggle("text-[13px]", enabled)
+    document.body.classList.toggle("font-[440]", enabled)
+  })
+
+  return null
+}
+
 function AppShellProviders(props: ParentProps) {
   return (
     <SettingsProvider>
+      <BodyDesignClass />
       <PermissionProvider>
         <LayoutProvider>
           <NotificationProvider>
diff --git a/packages/app/src/components/prompt-input.tsx b/packages/app/src/components/prompt-input.tsx
index e26217c90..84fe7495f 100644
--- a/packages/app/src/components/prompt-input.tsx
+++ b/packages/app/src/components/prompt-input.tsx
@@ -79,8 +79,6 @@ import { pathKey } from "@/utils/path-key"
 import { base64Encode } from "@opencode-ai/core/util/encode"
 import { displayName } from "@/pages/layout/helpers"
 
-const USE_V2_INPUT = import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"
-
 interface PromptInputProps {
   class?: string
   variant?: "dock" | "new-session"
@@ -1456,7 +1454,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
         t={(key) => language.t(key as Parameters<typeof language.t>[0])}
       />
       <Switch>
-        <Match when={USE_V2_INPUT}>
+        <Match when={settings.general.newLayoutDesigns()}>
           <div class="flex flex-col gap-3">
             <DockShellForm
               data-component={newSession() ? "session-new-composer" : "session-composer"}
@@ -1528,7 +1526,7 @@ export const PromptInput: Component<PromptInputProps> = (props) => {
                     onKeyDown={handleKeyDown}
                     classList={{
                       "select-text": true,
-                      "min-h-[52px] w-full px-4 pt-4 pb-2 focus:outline-none whitespace-pre-wrap leading-5 text-[13px] font-[440] text-v2-text-text-faint [font-family:Inter,var(--font-family-sans)]": true,
+                      "min-h-[52px] w-full px-4 pt-4 pb-2 focus:outline-none whitespace-pre-wrap leading-5 text-[13px] font-[440] text-v2-text-text-base": true,
                       "[&_[data-type=file]]:text-syntax-property": true,
                       "[&_[data-type=agent]]:text-syntax-type": true,
                       "font-mono!": store.mode === "shell",
diff --git a/packages/app/src/components/session/session-header.tsx b/packages/app/src/components/session/session-header.tsx
index f028f7cea..1c2cf47a7 100644
--- a/packages/app/src/components/session/session-header.tsx
+++ b/packages/app/src/components/session/session-header.tsx
@@ -45,8 +45,6 @@ const OPEN_APPS = [
   "sublime-text",
 ] as const
 
-const USE_V2_TITLEBAR = import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"
-
 type OpenApp = (typeof OPEN_APPS)[number]
 type OS = "macos" | "windows" | "linux" | "unknown"
 
@@ -157,11 +155,11 @@ export function SessionHeader() {
   })
   const hotkey = createMemo(() => command.keybind("file.open"))
   const os = createMemo(() => detectOS(platform))
-  const isDesktopV2 = platform.platform === "desktop" && USE_V2_TITLEBAR
-  const search = createMemo(() => (isDesktopV2 ? settings.general.showSearch() : true))
-  const tree = createMemo(() => (isDesktopV2 ? settings.general.showFileTree() : true))
-  const term = createMemo(() => (isDesktopV2 ? settings.general.showTerminal() : true))
-  const status = createMemo(() => (isDesktopV2 ? settings.general.showStatus() : true))
+  const isDesktopV2 = createMemo(() => platform.platform === "desktop" && settings.general.newLayoutDesigns())
+  const search = createMemo(() => (isDesktopV2() ? settings.general.showSearch() : true))
+  const tree = createMemo(() => (isDesktopV2() ? settings.general.showFileTree() : true))
+  const term = createMemo(() => (isDesktopV2() ? settings.general.showTerminal() : true))
+  const status = createMemo(() => (isDesktopV2() ? settings.general.showStatus() : true))
 
   const [exists, setExists] = createStore<Partial<Record<OpenApp, boolean>>>({
     finder: true,
diff --git a/packages/app/src/components/settings-general.tsx b/packages/app/src/components/settings-general.tsx
index 243aa6c36..bd95370a6 100644
--- a/packages/app/src/components/settings-general.tsx
+++ b/packages/app/src/components/settings-general.tsx
@@ -399,6 +399,18 @@ export const SettingsGeneral: Component = () => {
             />
           </div>
         </SettingsRow>
+
+        <SettingsRow
+          title={language.t("settings.general.row.newLayoutDesigns.title")}
+          description={language.t("settings.general.row.newLayoutDesigns.description")}
+        >
+          <div data-action="settings-new-layout-designs">
+            <Switch
+              checked={settings.general.newLayoutDesigns()}
+              onChange={(checked) => settings.general.setNewLayoutDesigns(checked)}
+            />
+          </div>
+        </SettingsRow>
       </SettingsList>
     </div>
   )
@@ -802,7 +814,7 @@ export const SettingsGeneral: Component = () => {
 
         <DisplaySection />
 
-        <Show when={desktop() && import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"}>
+        <Show when={desktop()}>
           <AdvancedSection />
         </Show>
       </div>
diff --git a/packages/app/src/components/titlebar.tsx b/packages/app/src/components/titlebar.tsx
index 2d956584a..d7a265384 100644
--- a/packages/app/src/components/titlebar.tsx
+++ b/packages/app/src/components/titlebar.tsx
@@ -55,7 +55,6 @@ const legacyTitlebarHeight = 40
 const v2TitlebarHeight = 44
 const minTitlebarZoom = 0.25
 const windowsControlsBaseWidth = 138 // 3 native Windows caption buttons at 46px each.
-const USE_V2_TITLEBAR = import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"
 
 const makeSessionHref = (b64Dir: string, sessionId: string) => `/${b64Dir}/session/${sessionId}`
 
@@ -75,6 +74,7 @@ export function Titlebar(props: { update?: TitlebarUpdate }) {
   const navigate = useNavigate()
   const location = useLocation()
   const params = useParams()
+  const useV2Titlebar = createMemo(() => settings.general.newLayoutDesigns())
 
   const mac = createMemo(() => platform.platform === "desktop" && platform.os === "macos")
   const windows = createMemo(() => platform.platform === "desktop" && platform.os === "windows")
@@ -85,7 +85,7 @@ export function Titlebar(props: { update?: TitlebarUpdate }) {
   const titlebarZoom = () => (windows() ? Math.max(zoom(), minTitlebarZoom) : zoom())
   const counterZoom = () => (windows() && titlebarZoom() < 1 ? 1 / titlebarZoom() : 1)
   const minHeight = () => {
-    const height = USE_V2_TITLEBAR ? v2TitlebarHeight : legacyTitlebarHeight
+    const height = useV2Titlebar() ? v2TitlebarHeight : legacyTitlebarHeight
     if (mac()) return `${height / zoom()}px`
     if (windows()) return `${height / Math.min(titlebarZoom(), 1)}px`
     return undefined
@@ -119,7 +119,7 @@ export function Titlebar(props: { update?: TitlebarUpdate }) {
   const canBack = createMemo(() => history.index > 0)
   const canForward = createMemo(() => history.index < history.stack.length - 1)
   const hasProjects = createMemo(() => layout.projects.list().length > 0)
-  const nav = createMemo(() => (USE_V2_TITLEBAR ? settings.general.showNavigation() : true))
+  const nav = createMemo(() => (useV2Titlebar() ? settings.general.showNavigation() : true))
   const updateState = createMemo<TitlebarUpdatePillState>(() => {
     const version = props.update?.version()
     return {
@@ -222,8 +222,8 @@ export function Titlebar(props: { update?: TitlebarUpdate }) {
     <header
       classList={{
         "shrink-0 relative overflow-hidden flex flex-row": true,
-        "h-11 bg-v2-background-bg-deep": USE_V2_TITLEBAR,
-        "h-10 bg-background-base": !USE_V2_TITLEBAR,
+        "h-11 bg-v2-background-bg-deep": useV2Titlebar(),
+        "h-10 bg-background-base": !useV2Titlebar(),
       }}
       style={{
         "min-height": minHeight(),
@@ -239,7 +239,7 @@ export function Titlebar(props: { update?: TitlebarUpdate }) {
       onDblClick={maximize}
     >
       <Switch>
-        <Match when={USE_V2_TITLEBAR}>
+        <Match when={useV2Titlebar()}>
           {(_) => {
             const serverSync = useServerSync()
             const navigate = useNavigate()
diff --git a/packages/app/src/context/settings.tsx b/packages/app/src/context/settings.tsx
index a4e01d53a..84288d31a 100644
--- a/packages/app/src/context/settings.tsx
+++ b/packages/app/src/context/settings.tsx
@@ -33,6 +33,7 @@ export interface Settings {
     editToolPartsExpanded: boolean
     showSessionProgressBar: boolean
     showCustomAgents: boolean
+    newLayoutDesigns?: boolean
   }
   updates: {
     startup: boolean
@@ -54,6 +55,7 @@ export interface Settings {
 export const monoDefault = "System Mono"
 export const sansDefault = "System Sans"
 export const terminalDefault = "JetBrainsMono Nerd Font Mono"
+export const newLayoutDesignsDefault = import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"
 
 const monoFallback =
   'ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace'
@@ -242,6 +244,10 @@ export const { use: useSettings, provider: SettingsProvider } = createSimpleCont
         setShowCustomAgents(value: boolean) {
           setStore("general", "showCustomAgents", value)
         },
+        newLayoutDesigns: withFallback(() => store.general?.newLayoutDesigns, newLayoutDesignsDefault),
+        setNewLayoutDesigns(value: boolean) {
+          setStore("general", "newLayoutDesigns", value)
+        },
       },
       updates: {
         startup: withFallback(() => store.updates?.startup, defaultSettings.updates.startup),
diff --git a/packages/app/src/i18n/en.ts b/packages/app/src/i18n/en.ts
index f58257b07..29f662f73 100644
--- a/packages/app/src/i18n/en.ts
+++ b/packages/app/src/i18n/en.ts
@@ -791,6 +791,8 @@ export const dict = {
   "settings.general.row.showSessionProgressBar.title": "Show session progress bar",
   "settings.general.row.showSessionProgressBar.description":
     "Display the animated progress bar at the top of the session when the agent is working",
+  "settings.general.row.newLayoutDesigns.title": "New layout and designs",
+  "settings.general.row.newLayoutDesigns.description": "Enable the redesigned layout, home, composer, and session UI",
   "settings.general.row.pinchZoom.title": "Pinch to zoom",
   "settings.general.row.pinchZoom.description": "Allow trackpad pinch and Ctrl-scroll gestures to zoom",
 
diff --git a/packages/app/src/pages/home.tsx b/packages/app/src/pages/home.tsx
index 2997efa56..96a44ffd8 100644
--- a/packages/app/src/pages/home.tsx
+++ b/packages/app/src/pages/home.tsx
@@ -31,8 +31,8 @@ import { messageAgentColor } from "@/utils/agent"
 import { sessionPermissionRequest } from "@/pages/session/composer/session-request-tree"
 import { ServerHealthIndicator } from "@/components/server/server-row"
 import { useServers } from "@/context/servers"
+import { useSettings } from "@/context/settings"
 
-const USE_HOME_DESIGN = import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"
 const HOME_SESSION_LIMIT = 15
 const HOME_ROW =
   "flex min-w-0 w-full shrink-0 cursor-default items-center rounded-[6px] border-0 bg-transparent text-left text-v2-text-text-muted transition-colors duration-[120ms] ease-in-out hover:bg-v2-overlay-simple-overlay-hover focus-visible:bg-v2-overlay-simple-overlay-hover focus-visible:outline-none"
@@ -52,8 +52,12 @@ type HomeSessionGroup = {
 }
 
 export default function Home() {
-  if (USE_HOME_DESIGN) return <HomeDesign />
-  return <LegacyHome />
+  const settings = useSettings()
+  return (
+    <Show when={settings.general.newLayoutDesigns()} fallback={<LegacyHome />}>
+      <HomeDesign />
+    </Show>
+  )
 }
 
 function HomeDesign() {
diff --git a/packages/app/src/pages/layout.tsx b/packages/app/src/pages/layout.tsx
index a943b436e..70154a34d 100644
--- a/packages/app/src/pages/layout.tsx
+++ b/packages/app/src/pages/layout.tsx
@@ -89,8 +89,6 @@ import {
 import { ProjectDragOverlay, SortableProject, type ProjectSidebarContext } from "./layout/sidebar-project"
 import { SidebarContent } from "./layout/sidebar-shell"
 
-const USE_NEW_DESIGN = import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"
-
 export default function Layout(props: ParentProps) {
   const [store, setStore, , ready] = persisted(
     Persist.global("layout.page", ["layout.page.v1"]),
@@ -129,6 +127,7 @@ export default function Layout(props: ParentProps) {
   const command = useCommand()
   const theme = useTheme()
   const language = useLanguage()
+  const newDesign = createMemo(() => settings.general.newLayoutDesigns())
   const initialDirectory = decode64(params.dir)
   const location = useLocation()
   const route = createMemo(() => {
@@ -154,7 +153,7 @@ export default function Layout(props: ParentProps) {
   const currentDir = createMemo(() => route().dir)
 
   const [state, setState] = createStore({
-    autoselect: !initialDirectory && !USE_NEW_DESIGN,
+    autoselect: !initialDirectory && !newDesign(),
     busyWorkspaces: {} as Record<string, boolean>,
     hoverProject: undefined as string | undefined,
     scrollSessionKey: undefined as string | undefined,
@@ -1142,7 +1141,7 @@ export default function Layout(props: ParentProps) {
       },
     ]
 
-    if (!USE_NEW_DESIGN)
+    if (!newDesign())
       Array.from({ length: 9 }, (_, i) => {
         const index = i
         const number = index + 1
@@ -1821,7 +1820,7 @@ export default function Layout(props: ParentProps) {
   createEffect(() => {
     document.documentElement.style.setProperty(
       "--dialog-left-margin",
-      USE_NEW_DESIGN ? "0px" : `${layout.sidebar.opened() ? layout.sidebar.width() : 48}px`,
+      newDesign() ? "0px" : `${layout.sidebar.opened() ? layout.sidebar.width() : 48}px`,
     )
   })
 
@@ -2363,179 +2362,180 @@ export default function Layout(props: ParentProps) {
     />
   )
 
-  if (USE_NEW_DESIGN) {
-    return (
-      <div class="relative bg-v2-background-bg-deep flex-1 min-h-0 min-w-0 flex flex-col select-none [&_input]:select-text [&_textarea]:select-text [&_[contenteditable]]:select-text">
+  return (
+    <Show
+      when={!newDesign()}
+      fallback={
+        <div class="relative bg-v2-background-bg-deep flex-1 min-h-0 min-w-0 flex flex-col select-none [&_input]:select-text [&_textarea]:select-text [&_[contenteditable]]:select-text">
+          {autoselecting() ?? ""}
+          <Titlebar update={titlebarUpdate} />
+          <main
+            class="flex-1 min-h-0 min-w-0 overflow-x-hidden flex flex-col items-start contain-strict bg-v2-background-bg-base"
+            classList={{
+              "m-2 mt-0 rounded-[10px] shadow-[var(--v2-elevation-raised)] overflow-hidden": !!params.id || !params.dir,
+            }}
+          >
+            <Show when={!autoselecting.loading} fallback={<div class="size-full" />}>
+              {props.children}
+            </Show>
+          </main>
+          {import.meta.env.DEV && <DebugBar />}
+          <Toast.Region />
+        </div>
+      }
+    >
+      <div class="relative bg-background-base flex-1 min-h-0 min-w-0 flex flex-col select-none [&_input]:select-text [&_textarea]:select-text [&_[contenteditable]]:select-text">
         {autoselecting() ?? ""}
         <Titlebar update={titlebarUpdate} />
-        <main
-          class="flex-1 min-h-0 min-w-0 overflow-x-hidden flex flex-col items-start contain-strict bg-v2-background-bg-base"
-          classList={{
-            "m-2 mt-0 rounded-[10px] shadow-[var(--v2-elevation-raised)] overflow-hidden": !!params.id || !params.dir,
-          }}
-        >
-          <Show when={!autoselecting.loading} fallback={<div class="size-full" />}>
-            {props.children}
-          </Show>
-        </main>
-        {import.meta.env.DEV && <DebugBar />}
-        <Toast.Region />
-      </div>
-    )
-  }
-
-  return (
-    <div class="relative bg-background-base flex-1 min-h-0 min-w-0 flex flex-col select-none [&_input]:select-text [&_textarea]:select-text [&_[contenteditable]]:select-text">
-      {autoselecting() ?? ""}
-      <Titlebar update={titlebarUpdate} />
-      <Show when={updateVersion() !== undefined}>
-        <UpdateAvailableToast version={updateVersion() ?? ""} install={installUpdate} language={language} />
-      </Show>
-      <div class="flex-1 min-h-0 min-w-0 flex">
-        <div class="flex-1 min-h-0 relative">
-          <div class="size-full relative overflow-x-hidden">
-            <nav
-              aria-label={language.t("sidebar.nav.projectsAndSessions")}
-              data-component="sidebar-nav-desktop"
-              classList={{
-                "hidden xl:block": true,
-                "absolute inset-y-0 left-0": true,
-                "z-10": true,
-              }}
-              style={{ width: `${side()}px` }}
-              ref={(el) => {
-                setState("nav", el)
-              }}
-              onMouseEnter={() => {
-                disarm()
-              }}
-              onMouseLeave={() => {
-                aim.reset()
-                if (!sidebarHovering()) return
-
-                arm()
-              }}
-            >
-              <div class="@container w-full h-full contain-strict">{sidebarContent()}</div>
-            </nav>
-
-            <Show when={layout.sidebar.opened()}>
-              <div
-                class="hidden xl:block absolute inset-y-0 z-30 w-0 overflow-visible"
-                style={{ left: `${side()}px` }}
-                onPointerDown={() => setState("sizing", true)}
-              >
-                <ResizeHandle
-                  direction="horizontal"
-                  size={layout.sidebar.width()}
-                  min={244}
-                  max={typeof window === "undefined" ? 1000 : window.innerWidth * 0.3 + 64}
-                  onResize={(w) => {
-                    setState("sizing", true)
-                    if (sizet !== undefined) clearTimeout(sizet)
-                    sizet = window.setTimeout(() => setState("sizing", false), 120)
-                    layout.sidebar.resize(w)
-                  }}
-                />
-              </div>
-            </Show>
-
-            <div
-              class="hidden xl:block pointer-events-none absolute top-0 right-0 z-0 border-t border-border-weaker-base"
-              style={{ left: "calc(4rem + 12px)" }}
-            />
-
-            <div class="xl:hidden">
-              <div
-                classList={{
-                  "fixed inset-x-0 top-10 bottom-0 z-40 transition-opacity duration-200": true,
-                  "opacity-100 pointer-events-auto": layout.mobileSidebar.opened(),
-                  "opacity-0 pointer-events-none": !layout.mobileSidebar.opened(),
-                }}
-                onClick={(e) => {
-                  if (e.target === e.currentTarget) layout.mobileSidebar.hide()
-                }}
-              />
+        <Show when={updateVersion() !== undefined}>
+          <UpdateAvailableToast version={updateVersion() ?? ""} install={installUpdate} language={language} />
+        </Show>
+        <div class="flex-1 min-h-0 min-w-0 flex">
+          <div class="flex-1 min-h-0 relative">
+            <div class="size-full relative overflow-x-hidden">
               <nav
                 aria-label={language.t("sidebar.nav.projectsAndSessions")}
-                data-component="sidebar-nav-mobile"
+                data-component="sidebar-nav-desktop"
                 classList={{
-                  "@container fixed top-10 bottom-0 left-0 z-50 w-full max-w-[400px] overflow-hidden border-r border-border-weaker-base bg-background-base transition-transform duration-200 ease-out": true,
-                  "translate-x-0": layout.mobileSidebar.opened(),
-                  "-translate-x-full": !layout.mobileSidebar.opened(),
+                  "hidden xl:block": true,
+                  "absolute inset-y-0 left-0": true,
+                  "z-10": true,
+                }}
+                style={{ width: `${side()}px` }}
+                ref={(el) => {
+                  setState("nav", el)
+                }}
+                onMouseEnter={() => {
+                  disarm()
+                }}
+                onMouseLeave={() => {
+                  aim.reset()
+                  if (!sidebarHovering()) return
+
+                  arm()
                 }}
-                onClick={(e) => e.stopPropagation()}
               >
-                {sidebarContent(true)}
+                <div class="@container w-full h-full contain-strict">{sidebarContent()}</div>
               </nav>
-            </div>
 
-            <div
-              classList={{
-                "absolute inset-0": true,
-                "xl:inset-y-0 xl:right-0 xl:left-[var(--main-left)]": true,
-                "z-20": true,
-                "transition-[left] duration-200 ease-[cubic-bezier(0.22,1,0.36,1)] will-change-[left] motion-reduce:transition-none":
-                  !state.sizing,
-              }}
-              style={{
-                "--main-left": layout.sidebar.opened() ? `${side()}px` : "4rem",
-              }}
-            >
-              <main
+              <Show when={layout.sidebar.opened()}>
+                <div
+                  class="hidden xl:block absolute inset-y-0 z-30 w-0 overflow-visible"
+                  style={{ left: `${side()}px` }}
+                  onPointerDown={() => setState("sizing", true)}
+                >
+                  <ResizeHandle
+                    direction="horizontal"
+                    size={layout.sidebar.width()}
+                    min={244}
+                    max={typeof window === "undefined" ? 1000 : window.innerWidth * 0.3 + 64}
+                    onResize={(w) => {
+                      setState("sizing", true)
+                      if (sizet !== undefined) clearTimeout(sizet)
+                      sizet = window.setTimeout(() => setState("sizing", false), 120)
+                      layout.sidebar.resize(w)
+                    }}
+                  />
+                </div>
+              </Show>
+
+              <div
+                class="hidden xl:block pointer-events-none absolute top-0 right-0 z-0 border-t border-border-weaker-base"
+                style={{ left: "calc(4rem + 12px)" }}
+              />
+
+              <div class="xl:hidden">
+                <div
+                  classList={{
+                    "fixed inset-x-0 top-10 bottom-0 z-40 transition-opacity duration-200": true,
+                    "opacity-100 pointer-events-auto": layout.mobileSidebar.opened(),
+                    "opacity-0 pointer-events-none": !layout.mobileSidebar.opened(),
+                  }}
+                  onClick={(e) => {
+                    if (e.target === e.currentTarget) layout.mobileSidebar.hide()
+                  }}
+                />
+                <nav
+                  aria-label={language.t("sidebar.nav.projectsAndSessions")}
+                  data-component="sidebar-nav-mobile"
+                  classList={{
+                    "@container fixed top-10 bottom-0 left-0 z-50 w-full max-w-[400px] overflow-hidden border-r border-border-weaker-base bg-background-base transition-transform duration-200 ease-out": true,
+                    "translate-x-0": layout.mobileSidebar.opened(),
+                    "-translate-x-full": !layout.mobileSidebar.opened(),
+                  }}
+                  onClick={(e) => e.stopPropagation()}
+                >
+                  {sidebarContent(true)}
+                </nav>
+              </div>
+
+              <div
                 classList={{
-                  "size-full overflow-x-hidden flex flex-col items-start contain-strict border-t border-border-weak-base bg-background-base xl:border-l xl:rounded-tl-[12px]": true,
+                  "absolute inset-0": true,
+                  "xl:inset-y-0 xl:right-0 xl:left-[var(--main-left)]": true,
+                  "z-20": true,
+                  "transition-[left] duration-200 ease-[cubic-bezier(0.22,1,0.36,1)] will-change-[left] motion-reduce:transition-none":
+                    !state.sizing,
+                }}
+                style={{
+                  "--main-left": layout.sidebar.opened() ? `${side()}px` : "4rem",
                 }}
               >
-                <Show when={!autoselecting.loading} fallback={<div class="size-full" />}>
-                  {props.children}
+                <main
+                  classList={{
+                    "size-full overflow-x-hidden flex flex-col items-start contain-strict border-t border-border-weak-base bg-background-base xl:border-l xl:rounded-tl-[12px]": true,
+                  }}
+                >
+                  <Show when={!autoselecting.loading} fallback={<div class="size-full" />}>
+                    {props.children}
+                  </Show>
+                </main>
+              </div>
+
+              <div
+                classList={{
+                  "hidden xl:flex absolute inset-y-0 left-16 z-30": true,
+                  "opacity-100 translate-x-0 pointer-events-auto": state.peeked && !layout.sidebar.opened(),
+                  "opacity-0 -translate-x-2 pointer-events-none": !state.peeked || layout.sidebar.opened(),
+                  "transition-[opacity,transform] motion-reduce:transition-none": true,
+                  "duration-180 ease-out": state.peeked && !layout.sidebar.opened(),
+                  "duration-120 ease-in": !state.peeked || layout.sidebar.opened(),
+                }}
+                onMouseMove={disarm}
+                onMouseEnter={() => {
+                  disarm()
+                  aim.reset()
+                }}
+                onPointerDown={disarm}
+                onMouseLeave={() => {
+                  arm()
+                }}
+              >
+                <Show when={peekProject()}>
+                  <SidebarPanel project={peekProject} merged={false} />
                 </Show>
-              </main>
-            </div>
+              </div>
 
-            <div
-              classList={{
-                "hidden xl:flex absolute inset-y-0 left-16 z-30": true,
-                "opacity-100 translate-x-0 pointer-events-auto": state.peeked && !layout.sidebar.opened(),
-                "opacity-0 -translate-x-2 pointer-events-none": !state.peeked || layout.sidebar.opened(),
-                "transition-[opacity,transform] motion-reduce:transition-none": true,
-                "duration-180 ease-out": state.peeked && !layout.sidebar.opened(),
-                "duration-120 ease-in": !state.peeked || layout.sidebar.opened(),
-              }}
-              onMouseMove={disarm}
-              onMouseEnter={() => {
-                disarm()
-                aim.reset()
-              }}
-              onPointerDown={disarm}
-              onMouseLeave={() => {
-                arm()
-              }}
-            >
-              <Show when={peekProject()}>
-                <SidebarPanel project={peekProject} merged={false} />
-              </Show>
-            </div>
-
-            <div
-              classList={{
-                "hidden xl:block pointer-events-none absolute inset-y-0 right-0 z-25 overflow-hidden": true,
-                "opacity-100 translate-x-0": state.peeked && !layout.sidebar.opened(),
-                "opacity-0 -translate-x-2": !state.peeked || layout.sidebar.opened(),
-                "transition-[opacity,transform] motion-reduce:transition-none": true,
-                "duration-180 ease-out": state.peeked && !layout.sidebar.opened(),
-                "duration-120 ease-in": !state.peeked || layout.sidebar.opened(),
-              }}
-              style={{ left: `calc(4rem + ${panel()}px)` }}
-            >
-              <div class="h-full w-px" style={{ "box-shadow": "var(--shadow-sidebar-overlay)" }} />
+              <div
+                classList={{
+                  "hidden xl:block pointer-events-none absolute inset-y-0 right-0 z-25 overflow-hidden": true,
+                  "opacity-100 translate-x-0": state.peeked && !layout.sidebar.opened(),
+                  "opacity-0 -translate-x-2": !state.peeked || layout.sidebar.opened(),
+                  "transition-[opacity,transform] motion-reduce:transition-none": true,
+                  "duration-180 ease-out": state.peeked && !layout.sidebar.opened(),
+                  "duration-120 ease-in": !state.peeked || layout.sidebar.opened(),
+                }}
+                style={{ left: `calc(4rem + ${panel()}px)` }}
+              >
+                <div class="h-full w-px" style={{ "box-shadow": "var(--shadow-sidebar-overlay)" }} />
+              </div>
             </div>
           </div>
+          {import.meta.env.DEV && <DebugBar />}
         </div>
-        {import.meta.env.DEV && <DebugBar />}
+        <Toast.Region />
       </div>
-      <Toast.Region />
-    </div>
+    </Show>
   )
 }
 
diff --git a/packages/app/src/pages/session.tsx b/packages/app/src/pages/session.tsx
index 6dadd898d..312b5c3a4 100644
--- a/packages/app/src/pages/session.tsx
+++ b/packages/app/src/pages/session.tsx
@@ -75,7 +75,6 @@ const emptyFollowups: FollowupItem[] = []
 
 type ChangeMode = "git" | "branch" | "turn"
 type VcsMode = "git" | "branch"
-const USE_NEW_SESSION_DESIGN = import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"
 
 type SessionHistoryWindowInput = {
   sessionID: () => string | undefined
@@ -198,6 +197,7 @@ export default function Page() {
   const [searchParams, setSearchParams] = useSearchParams<{ prompt?: string }>()
   const location = useLocation()
   const { params, sessionKey, tabs, view } = useSessionLayout()
+  const newSessionDesign = createMemo(() => settings.general.newLayoutDesigns())
 
   createEffect(() => {
     if (!prompt.ready()) return
@@ -265,7 +265,7 @@ export default function Page() {
   const isDesktop = createMediaQuery("(min-width: 768px)")
   const size = createSizing()
   const isV2NewSessionPage = () =>
-    shouldUseV2NewSessionPage({ channel: import.meta.env.VITE_OPENCODE_CHANNEL, sessionID: params.id })
+    shouldUseV2NewSessionPage({ newLayoutDesigns: newSessionDesign(), sessionID: params.id })
   const desktopReviewOpen = createMemo(() => isDesktop() && view().reviewPanel.opened() && !isV2NewSessionPage())
   const desktopFileTreeOpen = createMemo(() => isDesktop() && layout.fileTree.opened() && !isV2NewSessionPage())
   const desktopSidePanelOpen = createMemo(() => desktopReviewOpen() || desktopFileTreeOpen())
@@ -1798,14 +1798,14 @@ export default function Page() {
                 </Show>
               </Match>
               <Match when={true}>
-                <Show when={USE_NEW_SESSION_DESIGN} fallback={<NewSessionView worktree={newSessionWorktree()} />}>
+                <Show when={newSessionDesign()} fallback={<NewSessionView worktree={newSessionWorktree()} />}>
                   <NewSessionDesignView>{composerRegion("inline")}</NewSessionDesignView>
                 </Show>
               </Match>
             </Switch>
           </div>
 
-          <Show when={params.id || !USE_NEW_SESSION_DESIGN}>{composerRegion("dock")}</Show>
+          <Show when={params.id || !newSessionDesign()}>{composerRegion("dock")}</Show>
 
           <Show when={desktopReviewOpen()}>
             <div onPointerDown={() => size.start()}>
diff --git a/packages/app/src/pages/session/new-session-layout.test.ts b/packages/app/src/pages/session/new-session-layout.test.ts
index 4436763ab..436e0a59c 100644
--- a/packages/app/src/pages/session/new-session-layout.test.ts
+++ b/packages/app/src/pages/session/new-session-layout.test.ts
@@ -2,13 +2,13 @@ import { describe, expect, test } from "bun:test"
 import { shouldUseV2NewSessionPage } from "./new-session-layout"
 
 describe("shouldUseV2NewSessionPage", () => {
-  test("keeps prod session pages on the legacy layout", () => {
-    expect(shouldUseV2NewSessionPage({ channel: "prod", sessionID: "ses_123" })).toBe(false)
-    expect(shouldUseV2NewSessionPage({ channel: "prod" })).toBe(false)
+  test("keeps disabled pages on the legacy layout", () => {
+    expect(shouldUseV2NewSessionPage({ newLayoutDesigns: false, sessionID: "ses_123" })).toBe(false)
+    expect(shouldUseV2NewSessionPage({ newLayoutDesigns: false })).toBe(false)
   })
 
-  test("uses the v2 layout only for non-prod new-session pages", () => {
-    expect(shouldUseV2NewSessionPage({ channel: "dev" })).toBe(true)
-    expect(shouldUseV2NewSessionPage({ channel: "dev", sessionID: "ses_123" })).toBe(false)
+  test("uses the v2 layout only for enabled new-session pages", () => {
+    expect(shouldUseV2NewSessionPage({ newLayoutDesigns: true })).toBe(true)
+    expect(shouldUseV2NewSessionPage({ newLayoutDesigns: true, sessionID: "ses_123" })).toBe(false)
   })
 })
diff --git a/packages/app/src/pages/session/new-session-layout.ts b/packages/app/src/pages/session/new-session-layout.ts
index 4aa843360..f99558ddf 100644
--- a/packages/app/src/pages/session/new-session-layout.ts
+++ b/packages/app/src/pages/session/new-session-layout.ts
@@ -1,3 +1,3 @@
-export function shouldUseV2NewSessionPage(input: { channel?: "dev" | "beta" | "prod"; sessionID?: string }) {
-  return input.channel !== "prod" && !input.sessionID
+export function shouldUseV2NewSessionPage(input: { newLayoutDesigns: boolean; sessionID?: string }) {
+  return input.newLayoutDesigns && !input.sessionID
 }
diff --git a/packages/app/src/pages/session/session-side-panel.tsx b/packages/app/src/pages/session/session-side-panel.tsx
index 33c1d8a07..f73932dc4 100644
--- a/packages/app/src/pages/session/session-side-panel.tsx
+++ b/packages/app/src/pages/session/session-side-panel.tsx
@@ -28,8 +28,6 @@ import { createOpenSessionFileTab, createSessionTabs, getTabReorderIndex, type S
 import { setSessionHandoff } from "@/pages/session/handoff"
 import { useSessionLayout } from "@/pages/session/session-layout"
 
-const USE_DESKTOP_V2 = import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"
-
 type RenderDiff = (SnapshotFileDiff & { file: string }) | VcsFileDiff
 
 function renderDiff(value: SnapshotFileDiff | VcsFileDiff): value is RenderDiff {
@@ -60,7 +58,7 @@ export function SessionSidePanel(props: {
   const { sessionKey, tabs, view, params } = useSessionLayout()
 
   const isDesktop = createMediaQuery("(min-width: 768px)")
-  const desktopV2 = () => platform.platform === "desktop" && USE_DESKTOP_V2
+  const desktopV2 = () => platform.platform === "desktop" && settings.general.newLayoutDesigns()
   const shown = createMemo(() => (desktopV2() ? settings.general.showFileTree() : true))
 
   const reviewOpen = createMemo(() => isDesktop() && view().reviewPanel.opened())
@@ -205,7 +203,7 @@ export function SessionSidePanel(props: {
   })
 
   return (
-    <Show when={isDesktop() && !(import.meta.env.VITE_OPENCODE_CHANNEL !== "prod" && !params.id)}>
+    <Show when={isDesktop() && !(settings.general.newLayoutDesigns() && !params.id)}>
       <aside
         id="review-panel"
         aria-label={language.t("session.panel.reviewAndFiles")}
diff --git a/packages/app/src/pages/session/use-session-commands.tsx b/packages/app/src/pages/session/use-session-commands.tsx
index 3d348fc5f..a0252eb8d 100644
--- a/packages/app/src/pages/session/use-session-commands.tsx
+++ b/packages/app/src/pages/session/use-session-commands.tsx
@@ -20,8 +20,6 @@ import { extractPromptFromParts } from "@/utils/prompt"
 import { UserMessage } from "@opencode-ai/sdk/v2"
 import { useSessionLayout } from "@/pages/session/session-layout"
 
-const USE_DESKTOP_V2 = import.meta.env.VITE_OPENCODE_CHANNEL !== "prod"
-
 export type SessionCommandContext = {
   navigateMessageByOffset: (offset: number) => void
   setActiveMessage: (message: UserMessage | undefined) => void
@@ -72,7 +70,7 @@ export const useSessionCommands = (actions: SessionCommandContext) => {
   })
   const activeFileTab = tabState.activeFileTab
   const closableTab = tabState.closableTab
-  const desktopV2 = () => platform.platform === "desktop" && USE_DESKTOP_V2
+  const desktopV2 = () => platform.platform === "desktop" && settings.general.newLayoutDesigns()
   const shown = () => (desktopV2() ? settings.general.showFileTree() : true)
 
   const messages = () => {