Distillation

Date: Sep 9, 2026

• 🟡 (18:49) Inspection of packages/app/src/components/titlebar-tab-strip.tsx lines 380–450 found data-titlebar-tab-list renders class="flex w-full min-w-0" and switches between "flex-row items-center" when !vertical() and "flex-col gap-0.5" when vertical(); SessionTabEntry receives forceTruncate, vertical, and compact, while DraftTabSlot receives vertical.
• 🟡 (18:49) Inspection found TitlebarTabStrip displays left/right fade overlays only when !vertical(); vertical mode has no fade overlays.
• 🟡 (18:49) Assistant identified the cause of expanded rail tabs always stacking: vertical() becomes true whenever the rail is expanded.
• 🟡 (18:49) Assistant chose to make the rail’s vertical-layout decision width-aware at the TitlebarTabRail boundary, so wide expanded rails use existing compact row markup and narrow rails retain stacked metadata.
• 🔴 [continued-task] (23:06) User asked to continue the adaptive vertical-tab-rail task.
• 🟡 (23:06) Assistant planned to complete the width-aware rail change, then run app typecheck and server-build validation from their owning packages.